A 45-year-old woman is being examined as a candidate for cosmetic breast surgery. The surgeon notes that both of her breasts sag considerably. Which structure has most likely become stretched to result in this condition?

Suspensory (Coopers) ligaments

The suspensory ligaments of the breast, also known as Coopers ligaments, are fibrous bands that run from the dermis of the skin to the deep layer of superficial fascia and are primary supports for the breasts against gravity. Ptosis of the breast is usually due to the stretching of these ligaments and can be repaired with plastic surgery. Scarpas fascia is the deep membranous layer of superficial fascia of the anterior abdominal wall. The pectoralis major and pectoralis minor are muscles that move the upper limb and lie deep to the breast but do not provide any direct support structure to the breast. The serratus anterior muscle is involved in the movements of the scapula.

A 27-year-old man was admitted to the emergency department after an automobile collision in which he suffered a fracture of the lateral border of the scapula. Six weeks after the accident, physical examination reveals weakness in medial rotation and adduction of the humerus. Which nerve was most likely injured?

Lower subscapular

Lower subscapular nerves arise from the cervical spinal nerves 5 and 6. It innervates the subscapularis and teres major muscles. The subscapularis and teres major are both responsible for adducting and medially rotating the arm. A lesion of this nerve would result in weakness in these motions. The axillary nerve also arises from cervical spinal nerves 5 and 6 and innervates the deltoid and teres minor muscles. The deltoid muscle is large and covers the entire surface of the shoulder, and contributes to arm movement in any plane. The teres minor is a lateral rotator and a member of the rotator cuff group of muscles. The radial nerve arises from the posterior cord of the brachial plexus. It is the largest branch, and it innervates the triceps brachii and anconeus in the arm. The spinal accessory nerve is cranial nerve XI, and it innervates the trapezius muscle, which elevates and depresses the scapula. The ulnar nerve arises from the medial cord of the brachial plexus and runs down the medial aspect of the arm. It innervates muscles of the forearm and hand.

A 48-year-old female court stenographer is admitted to the orthopedic clinic with symptoms of carpal tunnel syndrome, with which she has suffered for almost a year. Which muscles most typically become weakened in this condition?

Thenar

The thenar muscles (and lumbricals I and II) are innervated by the median nerve, which runs through the carpal tunnel. The carpal tunnel is formed anteriorly by the flexor retinaculum and posteriorly by the carpal bones. Carpal tunnel syndrome is caused by a compression of the median nerve, due to reduced space in the carpal tunnel. The carpal tunnel contains the tendons of flexor pollicis longus, flexor digitorum profundus, and flexor digitorum superficialis muscles. The dorsal interossei, lumbricals III and IV, palmar interossei, and hypothenar muscles are all innervated by the ulnar nerve.

A 45-year-old male arrived at the emergency department with injuries to his left elbow after he fell in a bicycle race. Radiographic and MRI examinations show a fracture of the medial epicondyle and a torn ulnar nerve. Which of the following muscles would be most likely to be paralyzed?

Flexor carpi ulnaris

Fracture of the medial epicondyle often causes damage to the ulnar nerve due to its position in the groove behind the epicondyle. The ulnar nerve innervates one and a half muscles in the forearmthe flexor carpi ulnaris and the medial half of the flexor digitorum profundus. The nerve continues on to innervate muscles in the hand. The flexor digitorum superficialis is innervated by the median nerve and the biceps brachii by the musculocutaneous. The radial nerve innervates both the brachioradialis and supinator muscles.

While walking to his classroom building, a first-year medical student slipped on the wet pavement and fell against the curb, injuring his right arm. Radiographic images showed a midshaft fracture of the humerus. Which pair of structures was most likely injured at the fracture site?

Radial nerve and deep brachial artery

A midshaft humeral fracture can result in injury to the radial nerve and deep brachial artery because they lie in the spiral groove located in the midshaft. Injury to the median nerve and brachial artery can be caused by a supracondylar fracture that occurs by falling on an outstretched hand and partially flexed elbow. A fracture of the surgical neck of the humerus can injure the axillary nerve and posterior humeral circumflex artery. The suprascapular artery and nerve can be injured in a shoulder dislocation. The long thoracic nerve and lateral thoracic artery may be damaged during a mastectomy procedure.

An 18-year-old male is brought to the emergency department after an injury while playing
rugby. Imaging reveals a transverse fracture of the humerus about 1 inch proximal to the epicondyles. Which nerve is most frequently injured by the jagged edges of the broken bone at this location?

Median

A supracondylar fracture often results in injury to the median nerve. The course of the median nerve is anterolateral, and at the elbow it lies medial to the brachial artery on the brachialis muscle. The axillary nerve passes posteriorly through the quadrangular space, accompanied by the posterior circumflex humeral artery, and winds around the surgical neck of the humerus. Injury to the surgical neck may damage the axillary nerve. The musculocutaneous nerve pierces the coracobrachialis muscle and descends between the biceps and brachialis muscle. It continues into the forearm as the lateral antebrachial cutaneous nerve. The ulnar nerve descends behind the medial epicondyle in its groove and is easily injured and produces funny bone symptoms.

A 52-year-old band director suffered problems in her right arm several days after strenuous field exercises for a major athletic tournament. Examination in the orthopedic clinic reveals wrist drop and weakness of grasp but normal extension of the elbow joint. There is no loss of sensation in the affected limb. Which nerve was most likely affected?

Posterior interosseous

The radial nerve descends posteriorly between the long and lateral heads of the triceps and passes inferolaterally on the back of the humerus between the medial and lateral heads of the triceps. It eventually enters the anterior compartment and descends to enter the cubital fossa, where it divides into superficial and deep branches. The deep branch of the radial nerve winds laterally around the radius and runs between the two heads of the supinator and continues as the posterior interosseous nerve, innervating extensor muscles of the forearm. Because this injury does not result in loss of sensation over the skin of the upper limb, it is likely that the superficial branch of the radial nerve is not injured. If the radial nerve were injured very proximally, the woman would not have extension of her elbow. The branches of the radial nerve to the triceps arise proximal to where the nerve runs in the spiral groove. The anterior interosseous nerve arises from the median nerve and supplies the flexor digitorum profundus, flexor pollicis longus, and pronator quadratus, none of which seem to be injured in this example. Injury to the median nerve causes a characteristic flattening (atrophy) of the thenar eminence.

A 32-year-old woman is admitted to the emergency department after an automobile collision. Radiographic examination reveals multiple fractures of the humerus. Flexion and supination of the forearm are severely weakened. She also has loss of sensation on the lateral surface of the forearm. Which of the following nerves has most likely been injured?

Musculocutaneous

The musculocutaneous nerve supplies the biceps brachii and brachialis, which are the flexors of the forearm at the elbow. The musculocutaneous nerve continues as the lateral antebrachial cutaneous nerve, which supplies sensation to the lateral side of the forearm (with the forearm in the anatomic position). The biceps brachii is the most powerful supinator muscle. Injury to this nerve would result in weakness of supination and forearm flexion and lateral forearm sensory loss. Injury to the radial nerve would result in weakened extension and a characteristic wrist drop. Injury to the median nerve causes paralysis of flexor digitorum superficialis and other flexors in the forearm and results in a characteristic flattening of the thenar eminence. The lateral cord of the brachial plexus gives origin both to the musculocutaneous and lateral pectoral nerves. There is no indication of pectoral paralysis or weakness. Injury to the lateral cord can result in weakened flexion and supination in the forearm, and weakened adduction and medial rotation of the arm. The lateral cutaneous nerve of the forearm is a branch of the musculocutaneous nerve and does not supply any motor innervation. Injury to the musculocutaneous nerve alone is unusual but can follow penetrating injuries.

A 24-year-old medical student was bitten at the base of her thumb by her dog. The wound became infected and the infection spread into the radial bursa. The tendon(s) of which muscle will most likely be affected?

Flexor pollicis longus

Tenosynovitis can be due to an infection of the synovial sheaths of the digits. Tenosynovitis in the thumb may spread through the synovial sheath of the flexor pollicis longus tendon, also known as the radial bursa. The tendons of the flexor digitorum superficialis and profundus muscles are enveloped in the common synovial flexor sheath, or ulnar bursa. Neither the flexor carpi radialis nor flexor pollicis brevis tendons are contained in synovial flexor sheaths.

Laboratory studies in the outpatient clinic on a 24-year-old female included assessment of circulating blood chemistry. Which of the following arteries is most likely at risk during venipuncture at the cubital fossa?

Brachial

The three chief contents of the cubital fossa are the biceps brachii tendon, brachial artery, and median nerve (lateral to medial). The common and anterior interosseous arteries arise distal to the cubital fossa; the ulnar and radial arteries are the result of the bifurcation of the brachial artery distal to the cubital fossa

A 22-year-old male is diagnosed with metastatic malignant melanoma of the skin over the xiphoid process. Which nodes receive most of the lymph from this area and are therefore most likely to be involved in metastasis of the tumor?

Axillary

Lymph from the skin of the anterior chest wall primarily drains to the axillary lymph nodes.

A 49-year-old female who had suffered a myocardial infarction must undergo a bypass graft procedure using the internal thoracic artery. Which vessels will most likely continue to supply blood to the anterior part of the upper intercostal spaces?

Posterior intercostal

The anterior intercostal arteries are 12 small arteries, two in each of the upper six intercostal spaces at the upper and lower borders. The upper artery lying in each space anastomoses with the posterior intercostal arteries, whereas the lower one usually joins the collateral branch of the posterior intercostal artery. The musculophrenic artery supplies the pericardium, diaphragm, and muscles of the abdominal wall. It anastomoses with the deep circumflex iliac artery. The superior epigastric artery supplies the diaphragm, peritoneum, and the anterior abdominal wall and anastomoses with the inferior epigastric artery. The lateral thoracic artery runs along the lateral border of the pectoralis minor muscle and supplies the pectoralis major, pectoralis minor, and serratus anterior. The thoracodorsal artery accompanies the thoracodorsal nerve in supplying the latissimus dorsi muscle and lateral thoracic wall.

A 22-year-old woman is admitted to the emergency department in an unconscious state. The nurse takes a radial pulse to determine the heart rate of the patient. This pulse is felt lateral to which tendon?

Flexor carpi radialis

The location for palpation of the radial pulse is lateral to the tendon of the flexor carpi radialis, where the radial artery can be compressed against the distal radius. The radial pulse can also be felt in the anatomic snuffbox between the tendons of the extensor pollicis brevis and extensor pollicis longus muscles, where the radial artery can be compressed against the scaphoid.

A 45-year-old male is admitted to the hospital after accidentally walking through a plate glass door in a bar while intoxicated. Physical examination shows multiple lacerations to the upper limb, with inability to flex the distal interphalangeal joints of the fourth and fifth digits. Which of the following muscles is most likely affected?

Flexor digitorum profundus

The flexor digitorum profundus is dually innervated by the ulnar nerve to the medial phalanges and the median nerve for the lateral phalanges. Because of the superficial course of the ulnar nerve, it is vulnerable to laceration. Such an injury would result in an inability to flex the distal interphalangeal joints of the fourth and fifth digits. The flexor digitorum superficialis is innervated by the median nerve only, and the course of this nerve runs too deep to be affected by lacerations. The lumbricals function to flex the MP joints and assist in extending the IP joints. The interossei adduct and abduct the fingers.

A 24-year-old man is admitted with a wound to the palm of his hand. He cannot touch the pads of his fingers with his thumb but can grip a sheet of paper between all fingers and has no loss of sensation on the skin of his hand. Which of the following nerves has most likely been injured?

Recurrent branch of Median

The recurrent branch of the median nerve is motor to the muscles of the thenar eminence, which is an elevation caused by the abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis. If the opponens pollicis is paralyzed, one cannot oppose the pad of the thumb to the pads of the other digits. The recurrent branch does not have a cutaneous distribution. Holding a piece of paper between the fingers is a simple test of adduction of the fingers. These movements are controlled by the deep branch of the ulnar nerve, which is not injured in this patient.

A 55-year-old male is examined in a neighborhood clinic after receiving blunt trauma to his right axilla in a fall. He has difficulty elevating the right arm above the level of his shoulder. Physical examination shows the inferior angle of his right scapula protrudes more than the lower part of the left scapula. The right scapula protrudes far more when the patient pushes against resistance. Which of the following neural structures has most likely been injured?

The long thoracic

Winging of the scapula occurs when the medial border of the scapula lifts off the chest wall when the patient pushes against resistance, such as a wall. The serratus anterior muscle holds the medial border of the scapula against the chest wall and is innervated by the long thoracic nerve. The serratus anterior assists in abduction of the arm above the horizontal plane.

A mother tugs violently on her male childs hand to pull him out of the way of an oncoming car and the child screams in pain. Thereafter, it becomes obvious that the child cannot straighten his forearm at the elbow. When the child is seen in the emergency department, radiographic examination reveals a dislocation of the head of the radius. Which of the following ligaments is most likely directly associated with this injury?

Anular

The anular ligament is a fibrous band that encircles the head of the radius, forming a collar that fuses with the radial collateral ligament and articular capsule of the elbow. The anular ligament functions to prevent displacement of the head of the radius from its socket. The joint capsule functions to allow free rotation of the joint and does not function in its stabilization. The interosseous membrane is a fibrous layer between the radius and ulna helping to hold these two bones together. The radial collateral ligament extends from the lateral epicondyle to the margins of the radial notch of the ulnar and the anular ligament of the radius. The ulnar collateral ligament is triangular ligament and extends from the medial epicondyle to the olecranon of the ulna.

After a forceps delivery of a male infant, the baby presents with his left upper limb adducted, internally rotated, and flexed at the wrist. The startle reflex is absent on the ipsilateral side. Which part of the brachial plexus was most likely injured during this delivery?

Roots of the upper trunk

The injury being described is also known as Erb-Duchenne paralysis or waiters tip-hand. This usually results from an injury to the upper trunk of the brachial plexus, presenting with loss of abduction, flexion, and lateral rotation of the arm. The superior trunk of the brachial plexus consists of spinal nerve roots C5-6.

A 35-year-old patient has a small but painful tumor under the nail of the little finger. Which of the following nerves would have to be anesthetized for a painless removal of the tumor?

Common palmar digital of Ulnar

The common palmar digital branch comes off the superficial branch of the ulnar nerve and supplies the skin of the little finger and the medial side of the ring finger. The superficial branch of the radial nerve provides cutaneous innervation to the radial (lateral) dorsum of the hand and the radial two and a half digits over the proximal phalanx. The common palmar digital branch of the median nerve innervates most of the lateral aspect of the palmar hand and the dorsal aspect of the second and third finger as well as the lateral part of the fourth digit. The deep radial nerve supplies the extensor carpi radialis brevis and supinator muscles and continues as the posterior interosseous nerve. The recurrent branch of the median nerve supplies the abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis muscles.

A 25-year-old male athlete is admitted to the emergency department after a bad landing in the pole vault. Radiographic examination of his hand reveals a fractured carpal bone in the floor of the anatomic snuffbox. Which bone has most likely been fractured?

Scaphoid

The anatomic snuffbox is formed by the tendons of the extensor pollicis brevis, the abductor pollicis longus, and the extensor pollicis longus. The floor is formed by the scaphoid bone, and it is here that one can palpate for a possible fractured scaphoid.

A 36-year-old man is brought to the emergency department because of a deep knife wound on the medial side of his distal forearm. He is unable to hold a piece of paper between his fingers and has sensory loss on the medial side of his hand and little finger. Which nerve is most likely injured?

Ulnar

The ulnar nerve innervates the palmar interossei, which adduct the fingers. This is the movement that would maintain the paper between the fingers. The axillary nerve does not innervate muscles of the hand. The median nerve supplies the first and second lumbricals, the opponens pollicis, abductor pollicis brevis, and the flexor pollicis brevis. None of these muscles would affect the ability to hold a piece of paper between the fingers. The musculocutaneous and radial nerves do not supply muscles of the hand.

A 19-year-old man is brought to the emergency department after dislocating his shoulder while playing soccer. Following reduction of the dislocation, he has pain over the dorsal region of the shoulder and cannot abduct the arm normally. An MRI of the shoulder shows a torn muscle. Which of the following muscles is most likely to have been damaged by this injury?

Supraspinatus

The supraspinatus is one of the rotator cuff muscles. Its tendon is relatively avascular and is often injured when the shoulder is dislocated. This muscle initiates abduction of the arm, and damage would impair this movement. The coracobrachialis muscle, which runs from the coracoid process to the humerus, functions in adduction and flexion of the arm. The triceps main function is to extend the elbow, and damage to its long head would not affect abduction. The pectoralis minor functions as an accessory respiratory muscle and to stabilize the scapula and is not involved in abduction. The teres major functions to adduct and medially rotate the arm.

A 47-year-old female tennis professional is informed by her physician that she has a rotator cuff injury that will require surgery. Her physician explains that over the years of play a shoulder ligament has gradually caused severe damage to the underlying muscle. To which of the following ligaments is the physician most likely referring?

Coracoacromial ligament

The coracoacromial ligament contributes to the coracoacromial arch, preventing superior displacement of the head of the humerus. Because this ligament is very strong, it will rarely be damaged; instead, the ligament can cause inflammation or erosion of the tendon of the supraspinatus muscle as the tendon passes back and forth under the ligament. The acromioclavicular ligament, connecting the acromion with the lateral end of the clavicle, is not in contact with the supraspinatus tendon. The coracohumeral ligament is located too far anteriorly to impinge upon the supraspinatus tendon. The glenohumeral ligament is located deep to the rotator cuff muscles and would not contribute to injury of the supraspinatus muscle. The transverse scapular ligament crosses the scapular notch and is not in contact with the supraspinatus tendon.

A 69-year-old man has numbness in the middle three digits of his right hand and finds it difficult to grasp objects with that hand. He states that he retired 9 years earlier, after working as a carpenter for 50 years. He has atrophy of the thenar eminence. Which of the following conditions is the most likely cause of the problems in his hand?

Compression of the Median nerve in the carpal tunnel

The median nerve supplies sensory innervation to the thumb, index, and middle fingers and also to the lateral half of the ring finger. The median nerve also provides motor innervation to muscles of the thenar eminence. Compression of the median nerve in the carpal tunnel explains these deficits in conjunction with normal functioning of the flexor compartment of the forearm because these muscles are innervated by the median nerve proximal to the carpal tunnel. The ulnar nerve is not implicated in these symptoms. It does not provide sensation to digits 1 to 3. Compression of the brachial plexus could not be attributed to pressure from the triceps because this muscle is located distal to the plexus. In addition, brachial plexus symptoms would include other upper limb deficits, rather than the focal symptoms described in this case. Osteoarthritis of the cervical spine would also lead to increasing complexity of symptoms.

A 13-year-old boy is brought to the emergency department after losing control during a motorbike race in which he was run over by several of the other racers. Physical examination reveals several cuts and bruises. He is unable to extend the left wrist, fingers, and thumb, although he can extend the elbow. Sensation is lost in the lateral half of the dorsum of the left hand. Which of the following nerves has most likely been injured to result in these signs, and in what part of the arm is the injury located?

Radial nerve, midhumerus

The radial nerve innervates the extensor compartments of the arm and the forearm. It supplies the triceps brachii proximal to the spiral groove, so elbow extension is intact here. It also provides sensory innervation to much of the posterior arm and forearm as well as the dorsal thumb, index, and middle fingers up to the level of the fingernails. Symptoms are described only in the distal limb due to the midhumeral location of the lesion. The median nerve innervates flexors of the forearm and thenar muscles and provides sensory innervation to the lateral palmar hand. The ulnar nerve supplies only the flexor carpi ulnaris and the medial half of the flexor digitorum profundus in the forearm. Additionally, its sensory distribution is to both the palmar and dorsal aspects of the medial hand. It does not supply extensor muscles.

A 17-year-old male has weakness of elbow flexion and supination of the left hand after sustaining a knife wound in that arm in a street fight. Examination in the emergency department indicates that a nerve has been severed. Which of the following conditions will also most likely be seen during physical examination?

Sensory loss over the lateral surface of his forearm

The musculocutaneous nerve innervates the brachialis and biceps brachii muscles, which are the main flexors at the elbow. The biceps inserts on the radius and is an important supinator. Because the musculocutaneous nerve is damaged in this case, it leads to loss of sensory perception to the lateral forearm, which is supplied by the distal portion of the musculocutaneous nerve (known as the lateral antebrachial cutaneous nerve). Adduction and abduction of the fingers are mediated by the ulnar nerve and would not be affected in this instance. The flexor pollicis brevis flexes the thumb and is mainly innervated by the recurrent branch of the median nerve. Flexion of the fingers is performed by the long flexors of the fingers and lumbrical muscles, innervated by the median and ulnar nerves. Sensory innervation of the medial forearm is provided by the medial antebrachial cutaneous nerve, a branch of the medial cord of the brachial plexus.

Following several days of 12-hour daily rehearsals of the symphony orchestra for a performance of a Wagnerian opera, the 52-year-old male conductor experienced such excruciating pain in the posterior aspect of his right forearm that he could no longer direct the musicians. When the maestros forearm was palpated 2 cm distal to, and posteromedial to, the lateral epicondyle, the resulting excruciating pain caused the conductor to weep. Injections of steroids and rest were recommended to ease the pain. Which of the following injuries is most likely?

Compression of the Deep Radial Nerve by the Supinator

The deep radial nerve courses between the two heads of the supinator and is located just medial and distal to the lateral epicondyle. It can be irritated by hypertrophy of the supinator, which compresses the nerve, causing pain and weakness. The ulnar nerve courses laterally behind the medial epicondyle and continues anterior to the flexor carpi ulnaris. The median nerve passes into the forearm flexor compartment; the superficial radial nerve courses down the lateral aspect of the posterior forearm and would not cause pain due to pressure applied to the posterior forearm.

A 54-year-old female marathon runner presents with pain in her right wrist that resulted when she fell with force on her outstretched hand. Radiographic studies indicate an anterior dislocation of a carpal bone. Which of the following bones is most likely dislocated?

Lunate

The lunate is the most commonly dislocated carpal bone because of its shape and relatively weak ligaments anteriorly. Dislocations of the scaphoid and triquetrum are relatively rare. The trapezoid and capitate bones are located in the distal row of the carpal bones.

A 45-year-old man is admitted to the hospital after a car crash. Radiographic examination reveals mild disk herniations of C7, C8, and T1. The patient presents with a sensory deficit of the C8 and T1 spinal nerve dermatomes. The dorsal root ganglia of C8 and T1 would contain cell bodies of sensory fibers carried by which of the following nerves?

Medial antebrachial cutaneous nerve

The medial antebrachial cutaneous nerve carries sensory fibers derived from the C8 and T1 levels. The lateral antebrachial cutaneous nerve is the distal continuation of the musculocutaneous nerve, carrying fibers from the C5, C6, and C7 levels. The deep branch of the ulnar nerve and the anterior interosseous nerves carry predominantly motor fibers. The sensory fibers coursing in the radial nerve are derived from the C5 to C8 levels.

A 23-year-old female maid was making a bed in a hotel bedroom. As she straightened the sheet by running her right hand over the surface with her fingers extended, she caught the end of the index finger in a fold. She experienced a sudden, severe pain over the base of the terminal phalanx. Several hours later when the pain had diminished, she noted that the end of her right index finger was swollen and she could not completely extend the terminal interphalangeal joint. Which one of the following structures within the digit was most likely injured?

The insertion of the tendon of the Extensor Digitorum onto the base of the distal phalanx

The contraction of the extensor mechanism produces extension of the distal interphalangeal joint. When it is torn from the distal phalanx, the digit is pulled into flexion by the flexor digitorum profundus. The proper palmar digital branches of the median nerve supply lumbrical muscles and carry sensation from their respective digits. Vincula longa are slender, bandlike connections from the deep flexor tendons to the phalanx that can carry blood supply to the tendons. The insertions of the flexor digitorum superficialis and profundus are on the flexor surface of the middle and distal phalanges, respectively, and act to flex the interphalangeal joint.

A 45-year-old patient had fallen upon his outstretched hand, resulting in a Smith fracture of the distal end of the radius. The fractured bone displaced a carpal bone in the palmar direction, resulting in nerve compression within the carpal tunnel. Which of the following carpal bones will most likely be dislocated?

Lunate

In a Smith fracture, the distal fragment of the radius deviates palmarward, often displacing the lunate bone. The other listed bones are unlikely to be displaced in a palmar direction by a Smith fracture.

A 15-year-old girl was brought to the emergency department with a tear of the tendons in the first dorsal compartment of the wrist from a severe bite by a pit bull dog. The injured tendons in this compartment would include which of the following muscles?

Abductor pollicis longus and extensor pollicis brevis

The abductor pollicis longus and extensor pollicis brevis are the occupants of the first dorsal compartment of the wrist. The extensor carpi radialis longus and brevis are in the second compartment. The extensor digitorum is in the third compartment, as is the extensor indicis proprius. The extensor carpi ulnaris is located in the sixth dorsal compartment.

As she fell from the uneven parallel bars, the 17-year-old female gymnast grasped the lower bar briefly with one hand but then fell painfully to the floor. An MRI examination reveals an injury to the medial cord of the brachial plexus. Which of the following spinal nerve levels would most likely be affected?

C8, T1

The medial cord has been injured by traction on the lower trunk of the brachial plexus. The medial cord is the continuation of the inferior (lower) trunk of the brachial plexus, which is formed by C8 and T1. C5 and C6 are typically associated with the superior (upper) trunk level and thus the lateral cord. C7 forms the middle trunk. An injury to the posterior cord would usually involve the C7 spinal nerve. This is a typical Klumpke paralysis.

A 21-year-old female softball pitcher is examined in the emergency department after she was struck in the arm by a line drive (a ball hit very hard and low). Radiographic and MRI studies show soft tissue injury to the region of the spiral groove, with trauma to the radial nerve. Which of the following muscles would be intact after this injury?

Flexor carpi ulnaris

The flexor carpi ulnaris muscle is not innervated by the radial nerve but rather by the ulnar nerve. The brachioradialis, extensor carpi radialis, and supinator muscles are all innervated by the radial nerve distal to the spiral groove.

Examination of a 21-year-old female athlete with an injury of the radial nerve in the spiral groove would typically demonstrate which of the following physical signs?

Weakness of thumb abduction and thumb extension

Injury to the radial nerve in the spiral groove will paralyze the abductor pollicis longus and both extensors of the thumb. This injury will also lead to wrist drop (inability to extend the wrist). Weakness of grip would also occur, although this is not mentioned in the question. If the wrist is flexed, finger flexion and grip strength are weakened because the long flexor tendons are not under tension. Note how much your strength of grip is increased when your wrist is extended versus when it is flexed.

The 58-year-old convenience store operator had received a superficial bullet wound to the soft tissues on the medial side of the elbow in an attempted robbery. A major nerve was repaired at the site where it passed behind the medial epicondyle. Bleeding was stopped from an artery that accompanied the nerve in its path toward the epicondyle. Vascular repair was

The superior ulnar collateral artery

The superior ulnar collateral branch of the brachial artery accompanies the ulnar nerve in its path posterior to the medial epicondyle and is important in the blood supply of the nerve. The profunda brachii passes down the arm with the radial nerve. The radial collateral artery arises from the profunda brachii and anastomoses with the radial recurrent branch of the radial artery proximal to the elbow laterally. The inferior ulnar collateral artery arises from the brachial artery and accompanies the median nerve into the forearm. The anterior ulnar recurrent artery arises from the ulnar artery and anastomoses with the inferior ulnar collateral anterior to the elbow.

A 60-year-old male butcher accidentally slashed his wrist with his butcher knife, partially dividing the ulnar nerve. Which of the following actions would most likely be lost as a result of this injury?

Adduction of the fifth digit

Adduction of the fifth digit is produced by contraction of the third palmar interosseous muscle. All of the interossei are innervated by the deep branch of the ulnar nerve. Flexion of the proximal interphalangeal joint is a function of the flexor digitorum superficialis, supplied by the median nerve. Opposition of the thumb is a function of the opponens pollicis, supplied by the recurrent branch of the median nerve.

A 23-year-old male medical student fell asleep in his chair with Netters Atlas wedged into his axilla. When he awoke in the morning, he was unable to extend the forearm, wrist, or fingers. Movements of the ipsilateral shoulder joint appear to be normal. Which of the following nerves was most likely compressed, producing the symptoms described?

Radial nerve

The radial nerve is the most likely nerve compressed to cause these symptoms. This type of nerve palsy is often called Saturday night palsy. One reason for this nickname is that people would supposedly fall asleep after being intoxicated on a Saturday night with their arm over the back of a chair, thereby compressing the nerve in the spiral groove. The radial nerve innervates all of the extensors of the elbow, wrist, and fingers. Paralysis of the lateral cord of the brachial plexus would result in loss of the musculocutaneous nerve and the pectoral nerves, which do not mediate extension of the forearm or hand. The medial cord of the brachial plexus branches into the median nerve and ulnar nerve. Neither of these nerves innervates muscles that control extension. The median nerve innervates flexors of the forearm and the thenar muscles. The lateral and median pectoral nerves do not extend into the arm and innervate the pectoralis major and minor muscles.

The fact that the kidneys of a 32-year-old female patient were failing required that she be placed on dialysis. However, the search in her upper limb for a suitable vein was unexpectedly difficult. The major vein on the lateral side of the arm was too small; others were too delicate. Finally, a vein was found on the medial side of the arm that passed through the superficial and deep fascia to join veins beside the brachial artery. Which of the following veins was this?

Basilic

The basilic vein can be used for dialysis, especially when the cephalic vein is judged to be too small, as in this case. The basilic vein can be elevated from its position as it passes through the fascia on the medial side of the arm. The cephalic vein passes more laterally up the limb. The lateral cubital vein is a tributary to the cephalic vein, and the medial cubital vein joins the basilic veinboth rather superficial in position. The medial antebrachial vein courses up the midline of the forearm (antebrachium) ventrally.

A 29-year-old female had sustained a deep laceration in the proximal part of the forearm. After the wound is closed, the following functional deficits are observed by the neurologist on the service: The first three digits are in a position of extension and cannot be flexed. Digits 4 and 5 are partially flexed at the metacarpophalangeal joints and noticeably more flexed at the distal interphalangeal joints. Sensation is absent in the lateral side of the palm and the palmar surfaces of digits 1 to 3 and half of the fourth digit. Which of the following nerves has (have) most likely been injured?

Median Nerve

The patient exhibits the classic benediction attitude of the thumb and fingers from injury to the median nerve proximally in the forearm. The thumb is somewhat extended (radial supplied abductor and extensors unopposed); digits 2 and 3 are extended (by intact interossei); digits 4 and 5 are partially flexed (by their intact flexor digitorum profundus). A lesion of the median nerve would result in weakened flexion of the PIP joints of all digits (flexor digitorum superficialis), loss of flexion of the interphalangeal joint of the thumb, the DIP joints of digits 2 and 3 (flexor digitorum profundus), and weakened flexion of the metacarpophalangeal joints of the second and third digits (first and second lumbricals). A lesion of both the ulnar and median nerves would cause weakness or paralysis of flexion of all of the digits. A lesion of the ulnar nerve would mostly cause weakness in flexion of the DIP of the fourth and fifth digits and would affect all of the interosseous muscles and the lumbricals of the third and fourth digits. A lesion of the radial nerve would cause weakness in extension of the wrist, thumb, and metacarpophalangeal joints.

A 35-year-old male wrestler is admitted to the emergency department with excruciating pain in his right shoulder and proximal arm. During physical examination the patient clutches the arm at the elbow with his opposite hand and is unable to move the injured limb. Radiographic studies show that the patient has a dislocation of the humerus at the glenohumeral joint. Which of the following conditions is the most likely?

The head of the humerus is displaced inferiorly.

The head of the humerus is displaced inferiorly because in that location it is not supported by rotator cuff muscle tendons or the coracoacromial arch. It is also pulled anteriorly beneath the coracoid process by pectoralis and subscapularis muscles. It would not be displaced posteriorly because it is supported by the teres minor and infraspinatus muscle tendons. It would not be displaced superiorly because the acromioclavicular ligament and supraspinatus reinforce in that direction. A medial dislocation is blocked by the subscapularis tendon.

The 35-year-old female patient has a hard nodule about 1 cm in diameter slightly above and lateral to her right areola. A specific dye is injected into the tissue around the tumor, and an incision is made to expose the lymphatic vessels draining the area, for the lymphatic vessels take up the dyewhich is visible to the eye. The vessels can then be traced to surgically expose the lymph nodes receiving the lymph from the tumor. Which of the following nodes will most likely first encounter the lymph from the tumor?

Anterior axillary (pectoral) nodes

The anterior axillary (or anterior pectoral) nodes are the first lymph nodes to receive most of the lymph from the breast parenchyma, areola, and nipple. From there, lymph flows through central axillary, apical, and supraclavicular nodes in sequence. Rotters nodes lie between the pectoral muscles and are, unfortunately, an alternate route in some patients, speeding the rate of metastasis. The parasternal nodes receive lymph from the medial part of the breast and lie along the internal thoracic artery and vein.

During a fight in a tavern, a 45-year-old male construction worker received a shallow stab wound from a broken beer bottle at a point near the middle of the left posterior triangle of his neck. Upon physical examination it is observed that the left shoulder is drooping lower than the right shoulder, and the superior angle of the scapula juts out slightly. Strength in turning the head to the right or left appears to be symmetric. Which of the following nerves is most likely injured?

The spinal accessory nerve in the posterior cervical triangle

The left spinal accessory nerve has been injured distal to the sternocleidomastoid muscle, resulting in paralysis of the trapezius, allowing the shoulder to droop and the superior angle to push out posteriorly. The sternocleidomastoid muscles are intact, as demonstrated by symmetry in strength in turning the head to the right and left. There is no indication of paralysis of the lateral rotators of the shoulder or elbow flexors (suprascapular nerve or upper trunk). Thoracodorsal nerve injury would result in paralysis of the latissimus dorsi, an extensor, and medial rotator of the humerus.

A 44-year-old woman is diagnosed with radial nerve palsy. When muscle function is examined at the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints, what findings are most likely to be present?

Inability to extend the MCP joints only

Inability to extend MCP joints. The tendons of the extensor digitorum and extensor digiti minimi, innervated by the radial nerve, are responsible for extension of the MCP, and to a much lesser degree, the PIP and DIP joints. Abduction and adduction of the MCP joints are functions of the interossei, all of which are innervated by the deep ulnar nerve. Extension of the PIP and DIP joints is performed by the lumbricals and interossei. The first two lumbricals are supplied by the median nerve; the other lumbricals and the interossei, by the deep branch of the ulnar nerve.

A 27-year-old male painter is admitted to the hospital after falling from a ladder. Physical examination reveals that the patient is unable to abduct his arm more than 15° and cannot rotate the arm laterally. A radiographic examination reveals an oblique fracture of the humerus. He has associated sensory loss over the shoulder area. Which of the following injuries will most likely correspond to the symptoms of the physical examination?

Fracture of the surgical neck of the humerus

Fracture of the surgical neck of the humerus often injures the axillary nerve, which innervates the deltoid and teres minor muscles. Abduction of the humerus between 15° and the horizontal is performed by the deltoid muscle. Lateral rotation of the humerus is mainly performed by the deltoid muscle, teres minor, and the infraspinatus. The deltoid and teres minor are both lost in this case. Fracture of the glenoid fossa would lead to drooping of the shoulder. Fracture of the anatomic neck of the humerus will similarly lead to a drooping of the shoulder but would not necessarily affect abduction of the humerus. It is also quite unusual. Fracture of the middle third of the humerus would most likely injure the radial nerve. The ulnar nerve would be potentially compromised in a fracture of the medial epicondyle of the humerus.

A 47-year-old female patients right breast exhibited characteristics of peau dorange; that is, the skin resembled orange peel. This condition is primarily a result of which of the following?

Blockage of cutaneous lymphatic vessels

When cutaneous lymphatics of the breast are blocked by cancer, the skin becomes edematous, except where hair follicles cause small indentations of the skin, giving an overall resemblance to orange peel. Shortening of the suspensory ligaments or retinacula cutis leads to pitting of the overlying skin, pitting that is intensified if the patient raises her arm above her head. Invasion of the pectoralis major by cancer can result in fixation of the breast, seen upon elevation of the ipsilateral limb. Inversion of areolar skin with involvement of the ducts would also be due to involvement of the retinacula cutis.

A 29-year-old female is examined in the emergency department after falling from her balcony. Radiographic examination reveals that she has suffered a broken clavicle, with associated internal bleeding. Which of the following vessels is most likely to be injured in clavicular fractures?

Subclavian vein

The subclavian vein traverses between the clavicle and first rib and is the most superficial structure to be damaged following a fracture of the clavicle. The subclavian artery runs deep to the subclavian vein, and though it is in the appropriate location, it would likely not be damaged because of its deep anatomic position. The cephalic vein is a tributary to the axillary vein after ascending on the lateral side of the arm. Its location within the body is too superficial and lateral to the site of injury. The lateral thoracic artery is a branch from the axillary artery that runs lateral to the pectoralis minor. It courses inferior and medial from its point of origin from the axillary artery, and it does not maintain a position near the clavicle during its descent. The internal thoracic artery arises from the first part of the subclavian artery before descending deep to the costal cartilages. Its point of origin from the subclavian artery is lateral to clavicular injury. Furthermore, its course behind the costal cartilages is quite medial to the clavicular fracture.

A 68-year-old female is examined by the senior resident in emergency medicine after her fall on a wet bathroom floor in the shopping center. Physical examination reveals a posterior displacement of the left distal wrist and hand. Radiographic examination reveals an oblique fracture of the radius. Which of the following is the most likely fracture involved in this case?

Colles fracture

Colles fracture is a fracture of the distal end of the radius. The proximal portion of the radius is displaced anteriorly, with the distal bone fragment projecting posteriorly. The displacement of the radius from the wrist often gives the appearance of a dinner fork, thus a Colles fracture is often referred to as a dinner fork deformity. A scaphoid fracture results from a fracture of the scaphoid bone and would thus not cause displacement of the radius. This fracture usually occurs at the narrow aspect (waist) of the scaphoid bone. Bennetts and boxers fractures both result from fractures of the metacarpals (first and fifth, respectively). Volkmanns ischemic contracture is a muscular deformity that can follow a supracondylar fracture of the humerus, with arterial laceration into the flexor compartment of the forearm. Ischemia and muscle contracture, with extreme pain, accompany this fracture.

A 34-year-old female skier was taken by ambulance to the hospital after she struck a tree on the ski slope. Imaging gives evidence of a shoulder separation. Which of the following typically occurs in this kind of injury?

Partial or complete tearing of the coracoclavicular ligament

In shoulder separation, either or both the acromioclavicular and coracoclavicular ligaments can be partially or completely torn through. The acromioclavicular joint can be interrupted and the distal end of the clavicle may deviate upward in a complete separation, while the upper limb droops away inferiorly, causing a step off that can be palpated and sometimes observed. Displacement of the head of the humerus is shoulder dislocation, not separation. The coracoacromial ligament is not torn in separation (but it is sometimes used in the repair of the torn coracoclavicular ligament). Disruption of the glenoid labrum often accompanies shoulder dislocation.

A 22-year-old male construction worker is admitted to the hospital after he suffers a penetrating injury to his upper limb from a nail gun. Upon physical examination the patient is unable to flex the distal interphalangeal joints of digits 4 and 5. What is the most likely cause of his injury?

Trauma to the ulnar nerve near the trochlea

The nail was fired explosively from the nail gun and then pierced the ulnar nerve near the coronoid process of the ulna trochlea of the humerus. Paralysis of the medial half of the flexor digitorum profundus would result (among other significant deficits), with loss of flexion of the distal interphalangeal joints of digits 4 and 5. Ulnar trauma at the wrist would not affect the interphalangeal joints, although it would cause paralysis of interossei, hypothenar muscles, etc. Median nerve damage proximal to the pronator teres would affect proximal interphalangeal joint flexion and distal interphalangeal joint flexion of digits 2 and 3 as well as thumb flexion. Median nerve injury at the wrist would cause loss of thenar muscles but not long flexors of the fingers. Trauma to spinal nerve root C8 would affect all long finger flexors.

The shoulder of a 44-year-old deer hunter had been penetrated by a bolt released from a crossbow. The bolt had transected the axillary artery just beyond the origin of the subscapular artery. A compress is placed on the wound with deep pressure. After a clamp is placed on the bleeding artery, thought is given to the anatomy of the vessel. What collateral arterial pathways are available to bypass the site of injury?

Posterior humeral circumflex artery with deep brachial artery

The injury has occurred just beyond the third part of the axillary artery. The only collateral arterial channel between the third part of the axillary artery and the brachial artery is that between the posterior humeral circumflex and the ascending branch of the profunda brachiiand this anastomotic path is often inadequate to supply the arterial needs of the limb. The posterior humeral circumflex arises from the third part of the axillary artery. It typically anastomoses with a variably small, ascending branch of the profunda brachii branch of the brachial artery. The suprascapular artery anastomoses with the circumflex scapular deep to the infraspinatus. The dorsal scapular artery (passing beneath the medial border of the scapula) has no anastomosis with thoracodorsal within the scope of the injury. The lateral thoracic artery has no anastomoses with the brachial artery. The supreme thoracic artery (from first part of axillary) has no helpful anastomoses with the thoracoacromial (second part of axillary).

A 17-year-old male suffered the most common of fractures of the carpal bones when he fell on his outstretched hand. Which bone would this be?

Scaphoid

The scaphoid (or the older term, navicular) bone is the most commonly fractured carpal bone.

A 54-year-old male cotton farmer visits the outpatient clinic because of a penetrating injury to his forearm with a baling hook. After the limb is anesthetized, the site of the wound is opened and flushed thoroughly to remove all debris. The patient is not able to oppose the tip of the thumb to the tip of the index finger, as in making the OK sign. He is able to touch the tips of the ring and little fingers to the pad of his thumb. What nerve has most likely been injured?

Anterior interosseous

The anterior interosseous nerve is a branch of the median nerve that supplies the flexor pollicis longus, the lateral half of the flexor digitorum profundus, and the pronator quadratus. If it is injured, flexion of the interphalangeal joint of the thumb will be compromised. The median nerve gives rise to the anterior interosseous nerve but is not a direct enough answer as injury to it would result in more widespread effects. The posterior interosseous nerve supplies extensors in the forearm, not flexors. The radial nerve gives rise to the posterior interosseous nerve and is not associated with the anterior interosseous nerve; therefore, it would not have any effect on the flexors of the forearm. The recurrent median nerve is also a branch of the median nerve but supplies the thenar eminence muscles, and its injury would result in problems with opposable motion of the thumb.

Endoscopic examination of the shoulder of a 62-year-old female clearly demonstrated erosion of the tendon within the glenohumeral joint. What tendon was this?

Long head of biceps

The tendon of the long head of the biceps brachii muscle passes through the glenohumeral joint, surrounded by synovial membrane. The glenohumeral is a ligament that attaches to the glenoid labrum. The long head of the triceps arises from the infraglenoid tubercle, beneath the glenoid fossa. The infraspinatus tendon passes posterior to the head of the humerus to insert on the greater tubercle. The coracobrachialis arises from the coracoid process and inserts on the humerus.

The orthopedic surgeon exposed the muscle in the supraspinous fossa so that she could move it laterally, in repair of an injured rotator cuff. As she reflected the muscle from its bed, an artery was exposed crossing the ligament that bridges the notch in the superior border of the scapula. What artery was this?

Suprascapular

The suprascapular artery passes over, and the suprascapular nerve passes under, the superior transverse scapular ligament. This ligament bridges the suprascapular notch in the upper border of the scapula. The artery and nerve then pass deep to the supraspinatus muscle, thereafter supplying it and then passing through the spinoglenoid notch to supply the infraspinatus. The subscapular artery is a branch of the third part of the axillary artery; it divides into circumflex scapular and thoracodorsal branches. The transverse cervical artery courses anterior to this site. The dorsal scapular artery and nerve pass deep to the medial border of the scapula. The posterior humeral circumflex branch of the axillary artery passes through the quadrangular space with the axillary nerve.

A 61-year-old man was hit by the cricket bat in the midhumeral region of his left arm. Physical examination reveals an inability to extend the wrist and loss of sensation on a small area of skin on the dorsum of the hand proximal to the first two fingers. What nerve supplies this specific region of the hand?

Radial

The patient has suffered injury to the radial nerve in the midhumeral region. The nerve that provides sensation to the dorsum of the hand proximal to the thumb and index finger is the superficial branch of the radial nerve. The posterior interosseous nerve supplies a strip of skin on the back of the forearm and wrist extensors. The lateral antebrachial cutaneous nerve is a continuation of the musculocutaneous nerve and supplies the lateral side of the forearm. The medial antebrachial cutaneous is a direct branch of the medial cord and supplies skin of the medial side of the forearm. The dorsal cutaneous branch of the ulnar nerve supplies the medial side of the dorsum of the hand.

A 45-year-old woman is admitted to the hospital with neck pain. An MRI examination reveals a herniated disk in the cervical region. Physical examination reveals weakness in wrist extension and paraesthesia on the back of her arm and forearm. Which of the following spinal nerves is most likely injured?

C7

The seventh cervical nerve makes a major contribution to the radial nerve, and this nerve is the prime mover in wrist extension. The dermatome of C7 is in the region described.

A 22-year-old male football player suffered a wrist injury while falling with force on his outstretched hand. When the anatomic snuffbox is exposed in surgery, an artery is visualized crossing the fractured bone that provides a floor for this space. What artery was visualized?

Radial

As the radial artery passes from the ventral surface of the wrist to the dorsum, it crosses through the anatomic snuffbox, passing over the scaphoid bone. The ulnar artery at the wrist is located on the medial side of the wrist, passing from beneath the flexor carpi ulnaris to reach Guyons canal between the pisiform bone and the flexor retinaculum. The anterior interosseous and posterior interosseous arteries arise from the common interosseous branch of the ulnar artery and pass proximal to distal in the forearm between the radius and ulna, in the flexor and extensor compartments, respectively. The deep palmar branch of the ulnar artery passes between the two heads of the adductor pollicis to anastomose with the radial artery in the palm.

The right shoulder of a 78-year-old female had become increasingly painful over the past year. Abduction of the right arm caused her to wince from the discomfort. Palpation of the deltoid muscle by the physician produced exquisite pain. Imaging studies reveal intermuscular inflammation extending over the head of the humerus. What structure was inflamed?

Subacromial bursa

The patient is suffering from subacromial or subdeltoid bursitis. (If the pain on palpation is less when the arm has been elevated to the horizontal, the bursitis may be thought of as being more subacromial, that is, associated more with the supraspinatus tendon perhaps, for such a bursa may be drawn back under the acromion when the limb is abducted.) The subscapular bursa, beneath the subscapularis muscle, would not present as superficial pain. It can communicate with the glenohumeral joint cavity. Inflammation or arthritic changes within the glenohumeral joint present as more generalized shoulder pain than that present here. The teres minor muscle and tendon are located inferior to the point of marked discomfort.

A 55-year-old male metallurgist had been diagnosed with carpal tunnel syndrome. To begin the operation, an anesthetic injection into his axillary sheath was used instead of a general anesthesia. From which of the following structures does the axillary sheath take origin?

Prevertebral fascia

The axillary sheath is a fascial continuation of the prevertebral layer of the deep cervical fascia extending into the axilla. It encloses the nerves of the neurovascular bundle of the upper limb. Superficial fascia is loose connective tissue between the dermis and the deep investing fascia and contains fat, cutaneous vessels, nerves, lymphatics, and glands. The buccopharyngeal fascia covers the buccinator muscles and the pharynx mingles with the pretrachial fascia. The clavipectoral muscle invests the clavicle and pectoralis minor muscle. The axillary fascia is continuous with the pectoral and latissimus dorsi fascia and forms the hollow of the armpit.

A 45-year-old woman is admitted to the hospital with neck pain. A CT scan reveals a tumor in the left side of her oral cavity. The tumor and related tissues are removed with a radical neck surgical procedure. Two months postoperatively the patients left shoulder droops quite noticeably. Physical examination reveals distinct weakness in turning her head to the right and impairment of abduction of her left upper limb to the level of the shoulder. Which of the following structures was most likely injured during the radical neck surgery?

Spinal accessory nerve

The spinal accessory nerve arises from the ventral rootlets of C1 to C4 and ascends through the foramen magnum to then exit the cranial cavity through the jugular foramen. It innervates the sternocleidomastoid and trapezius muscles, which function in head rotation and raising of the shoulders. The suprascapular nerve receives fibers from C5-6 (occasionally from C4 if the plexus is prefixed) and innervates the supraspinatus muscle, which is responsible for the first 15° of arm abduction. Erb point of the brachial plexus is at the union of C5-6 spinal nerves. The long thoracic nerve arises from plexus routes C5, 6, and 7, and supplies the serratus anterior.

A 23-year-old male basketball player is admitted to the hospital after injuring his shoulder during a game. Physical and radiographic examinations reveal total separation of the shoulder. Which of the following structures has most likely been torn?

Acromioclavicular ligament

The acromioclavicular ligament connects the clavicle to the coracoid process of the scapula. Separation of the shoulder (dislocation of the acromioclavicular [AC] joint) is associated with damage to the acromioclavicar ligament (capsule of the AC joint) and, in more severe injuries, disruption of the coracoclavicular ligaments (conoid and trapezoid portions). The glenohumeral ligament may be injured by an anterior dislocation of the humerus but is not likely to be injured by a separated shoulder. The coracoacromial ligament, transverse scapular ligament, and tendon of the long head of triceps brachii are not likely to be injured by separation of the shoulder.

A 35-year-old male body builder has enlarged his shoulder muscles to such a degree that the size of the quadrangular space is greatly reduced. Which of the following structures would most likely be compressed in this condition?

Axillary nerve

The quadrangular space is bordered medially by the long head of the triceps, laterally by the surgical neck of the humerus, superiorly by the teres minor and subscapularis muscles, and inferiorly by the teres major muscle. Both the axillary nerve and posterior humeral circumflex vessels traverse this space. The other structures listed are not contained within the quadrangular space. The cephalic vein is located in the deltopectoral triangle, and the radial nerve is located in the triangular interval.

A 43-year-old woman visits the outpatient clinic with a neurologic problem. Diagnostically, she cannot hold a piece of paper between her thumb and the lateral side of her index finger without flexing the distal joint of her thumb. This is a positive Froment sign and a diagnosis of ulnar neuropathy. Weakness of which specific muscle causes this sign to appear?

Adductor pollicis

Froments sign is positive for ulnar nerve palsy. More specifically it tests the action of the adductor pollicis muscle. The patient is asked to hold a sheet of paper between the thumb and a flat palm. The flexor pollicis longus is innervated by the anterior interosseous branch of the median nerve. The flexor digiti minimi is innervated by the deep branch of the ulnar nerve and would not be used to hold a sheet of paper between the thumb and palm. The flexor carpi radialis is innervated by the median nerve, and the extensor indicis is innervated by the radial nerve.

A 48-year-old female piano player visited the outpatient clinic with numbness and tingling in her left hand. A diagnosis was made of nerve compression in the carpal tunnel, and the patient underwent an endoscopic nerve release. Two weeks postoperatively the patient complained of a profound weakness in the thumb, with loss of thumb opposition. The sensation to the hand, however, was unaffected. Which of the following nerves was injured during the operation?

Recurrent branch of median nerve

The recurrent branch of the median nerve innervates the thenar muscles (opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis) and is not responsible for any cutaneous innervation. Damage to the palmar cutaneous branches of the median nerve or to the ulnar nerve would not cause weakness of opposition of the thumb for they are principally sensory in function. The deep branch of the ulnar nerve supplies the hypothenar muscles, adductor and abductor muscles of digits 25, and does not innervate the abductor policis brevis.

A 19-year-old male had suffered a deep laceration to an upper limb when he stumbled and fell on a broken bottle. On examination of hand function it is observed that he is able to extend the metacarpophalangeal joints of all his fingers in the affected limb. He cannot extend the interphalangeal joints of the fourth and fifth digits, and extension of the interphalangeal joints of the second and third digits is very weak. There is no apparent sensory deficit in the hand. Which of the following nerves has most likely been injured?

Deep branch of ulnar nerve

Injury to the deep branch of the ulnar nerve results in paralysis of all interosseous muscles and the lumbrical muscles of digits 4 and 5. Extension of the metacarpophalangeal joints is intact, a function of the radial nerve. Interphalangeal extension of digits 4 and 5 is absent, due to the loss of all interosseous muscle and the lumbricals of digits 4 and 5. Some weak interphalangeal joint extension is still present in digits 2 and 3 because the lumbricals of these two fingers are innervated by the median nerve. The radial nerve and the median nerve appear to be intact in this case. If the ulnar nerve were injured in the midforearm region, there would be sensory loss in the palm and digits 4 and 5 and on the dorsum of the hand. The recurrent branch of the median nerve supplies the thenar muscles; it does not supply lumbricals. Moreover, paralysis of this nerve would have no effect on the interphalangeal joints.

A 41-year-old woman is scheduled for a latissimus dorsi muscle flap to cosmetically augment the site of her absent left breast, postmastectomy. Part of the latissimus dorsi muscle is advanced to the anterior thoracic wall, based upon arterial supply provided in part by the artery that passes through the triangular space of the axilla. What artery is forming the vascular base of this flap?

Circumflex scapular artery

The circumflex scapular artery passes through the triangular space after arising from the subscapular artery. It provides superficial branches to the overlying latissimus dorsi, whereas its deep portion passes into the infraspinous fossa to anastomose with the suprascapular artery. The dorsal scapular artery passes between the roots of the brachial plexus and then deep to the medial border of the scapula. The transverse cervical artery arises from the thyrocervical trunk at the root of the neck and can provide origin for a dorsal scapular branch. The lateral thoracic and thoracoacromial arteries are branches of the second part of the axillary artery and provide no supply to the latissimus dorsi.

A 31-year-old male hockey player fell on his elbow and is admitted to the emergency department. Radiographic examination reveals a fracture of the surgical neck of the humerus, producing an elevation and adduction of the distal fragment. Which of the following muscles would most likely cause the adduction of the distal fragment?

Pectoralis major

The surgical neck of the humerus is a typical site of fractures. The fracture line lies above the insertions of the pectoralis major, teres major, and latissimus dorsi muscles. The supraspinatus muscle abducts the proximal fragment, whereas the distal fragment is elevated and adducted. The elevation results from contraction of the deltoid, biceps brachii, and coracobrachialis muscles. The adduction is due to the action of pectoralis major, teres major, and latissimus dorsi.

A 74-year-old woman is admitted to the emergency department after stumbling over her pet dog. Radiographic examination reveals a fracture of the upper third of the right radius, with the distal fragment of the radius and hand pronated. The proximal end of the fractured radius deviates laterally. Which of the following muscles is primarily responsible for the lateral deviation?

Supinator

The fracture line of the upper third of the radius lies between the bony attachments of the supinator and the pronator teres muscles. The distal radial fragment and hand are pronated due to unopposed contraction of pronator teres and pronator quadratus muscles. The proximal fragment deviates laterally by the unopposed contraction of the supinator muscle. The brachioradialis inserts distally on the radius. The brachialis inserts on the coronoid process of the ulna and would not be involved in the lateral deviation of the radius.

A 12-year-old male had received a laceration in the palmar surface of the wrist while playing with a very sharp knife. The cut ends of a tendon could be seen within the wound in the exact midline of the wrist. Which tendon lies in this position in most people?

Palmaris longus

The palmaris longus passes along the midline of the flexor surface of the forearm. The flexor carpi radialis is seen in the lateral portion of the forearm superficially, passing over the trapezium to insert at the base of the second metacarpal. The abductor pollicis longus tendon is laterally located in the wrist, where it helps form the lateral border of the anatomic snuffbox. The flexor carpi ulnaris tendon can be seen and palpated on the medial side of the wrist ventrally. The flexor pollicis longus tendon passes deep through the carpal tunnel.

A 22-year-old male medical student was seen in the emergency department with a complaint of pain in his hand. He confessed that he had hit a vending machine in the hospital when he did not receive his soft drink after inserting money twice. The medial side of the dorsum of the hand was quite swollen, and one of his knuckles could not be seen when he made a fist. The physician made a diagnosis of a boxers fracture. What was the nature of the impatient students injury?

Fracture of the neck of the fifth metacarpal

The student had broken the neck of the fifth metacarpal when hitting the machine with his fist. This is the more common type of boxers fracture. Neither a fracture of the ulnar styloid nor a Colles fracture nor a Smith fracture of the distal radius would present with the absence of a knuckle as observed here. Bennetts fracture involves dislocation of the carpometacarpal joint of the thumb. Indications are that the injury is on the medial side of the hand, not the wrist, nor the lateral side of the hand or wrist.

Fine motor function in the right hand of a 14-year-old female with scoliosis since birth appeared to be quite reduced, including thumb opposition, abduction and adduction of the digits, and interphalangeal joint extension. Radiography confirmed that her severe scoliosis was causing marked elevation of the right first rib. Long flexor muscles of the hand and long extensors of the wrist appear to be functioning within normal limits. There is notable anesthesia of the skin on the medial side of the forearm; otherwise, sensory function in the limb is intact. Which of the following neural structures is most likely impaired?

T1 nerve root

Scoliosis (severe, lateral curvature of the spine) in the patient is causing compression or stretching of the T1 spinal nerve root by the first rib as the nerve ascends to join C8 and form the lower trunk of the brachial plexus. T1 provides sensation for the medial side of the forearm, via the medial antebrachial cutaneous nerve from the medial cord of the brachial plexus. T1 is the principal source of motor supply to all of the intrinsic muscles in the palm. Its dysfunction affects all fine motor movements of the digits. Long flexors of the fingers are intact; therefore, the median nerve and ulnar nerve are not at fault. The extensors of the wrist are functional; therefore, the radial nerve is not paralyzed. The only sensory disturbance is that of the T1 dermatome.

A 23-year-old female had a painful injury to her hand in a dry ski-slope competition, in which she fell and caught her thumb in the matting. Radiographic and physical examinations reveal rupture of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb. Lidocaine is injected into the area to relieve the pain, and she is scheduled for a surgical repair. From which of the following clinical problems is she suffering?

Gamekeepers thumb

Interestingly, gamekeepers thumb was a term coined because this injury was most commonly associated with Scottish gamekeepers who, it is said, killed small animals such as rabbits by breaking their necks between the ground and the gamekeepers thumb and index finger. The resulting valgus force on the abducted MCP joint caused injury to the ulnar collateral ligament. These days this injury is more commonly seen in skiers who land awkwardly with their hand braced on a ski pole, causing the valgus force on the thumb as is seen in this patient. Whereas the term skier thumb is sometimes used, gamekeepers thumb is still in common usage.

A 26-year-old male power lifter visits the outpatient clinic with a painful shoulder. Radiographic examination reveals tendinopathy of the long head of the biceps. Which of the following conditions will most likely be present during physical examination?

Pain is felt in the anterior shoulder during forced contraction.

The long head of the biceps assists in shoulder flexion and during a tendinopathy would cause pain in the anterior compartment of the shoulder, where it originates at the supraglenoid tubercle. Also, forced contraction would cause more of a greater tension force on the tendon.

A 43-year-old female tennis player visits the outpatient clinic with pain over the right lateral epicondyle of her elbow. Physical examination reveals that the patient has lateral epicondylitis. Which of the following tests should be performed during physical examination to confirm the diagnosis?

Observing the presence of pain when the wrist is extended against resistance

The common extensor tendon originates from the lateral epicondyle, and inflammation of this tendon is lateral epicondylitis, nicknamed tennis elbow because the tendon is often irritated during the backhand stroke in tennis. Because the extensors of the wrist originate as part of the common extensor tendon, extension of the wrist will exacerbate the pain of lateral epicondylitis.

A male skier had a painful fall against a rocky ledge. Radiographic findings revealed a hairline fracture of the surgical neck of the humerus. The third-year medical student assigned to this patient was asked to determine whether there was injury to the nerve associated with the area of injury. Which of the following tests would be best for checking the status of the nerve?

Test for presence of skin sensation over the lateral side of the shoulder.

The axillary nerve passes dorsally around the surgical neck of the humerus (accompanied by the posterior humeral circumflex artery) and can be injured when the humerus is fractured at that location. The axillary nerve provides sensation to the skin over the upper, lateral aspect of the shoulder. Therefore, although the patient might not be able to abduct the arm because of the injury, a simple test of skin sensation can indicate whether there is associated nerve injury of the axillary nerve. Shrugging the shoulders can help assess trapezius function, thereby testing the spinal accessory nerve. Intact sensation of the skin on the medial aspect of the axilla or arm is an indication that the radial or intercostobrachial nerves are functional. Pushing against an immovable object tests the serratus anterior muscle and the long thoracic nerve.

A 27-year-old male had lost much of the soft tissue on the dorsum of his left hand in a motorcycle crash. Imaging studies show no other upper limb injuries. Because the left extensor carpi radialis longus and brevis tendons were lost, it was decided to replace those tendons with the palmaris longus tendons from both forearms because of those tendons convenient location and relative unimportance. Postoperatively it is found that sensation is absent in both hands on the lateral palm and palmar surfaces of the first three digits; there is also paralysis of thumb opposition. What is the most likely cause of the sensory deficit and motor loss in both thumbs?

The palmaris longus was absent bilaterally; the nerve beneath it looked like a tendon.

The surgeon took the distal segments of the median nerves from both forearms, mistakenly believing them to be palmaris longus tendons. Both of the structures lie in the midline of the ventral surface of the distal forearm and are often of similar appearance in color and diameter. The nerve is located deep to the tendon, when the tendon is present, but when the tendon is absent, the nerve appears to be where the tendon belongs. There is no evidence of rib fractures; even so, a fractured rib would not explain loss of sensation on the lateral portion of the palm. Lower plexus trauma (C8, T1) would result in paralysis of forearm flexor muscles and all intrinsic hand muscles and sensory loss over the medial dorsum of the hand, in addition to palmar sensory loss. Dupuytrens contracture is a flexion contracture of (usually) digits 4 and 5 from connective tissue disease in the palm. Radial nerve injury in the posterior forearm would affect metacarpophalangeal joint extension, thumb extension, etc., not palmar disturbances.

A 15-year-old male received a shotgun wound to the ventral surface of the upper limb. Upon examination it is quickly observed that the patient exhibits a complete clawhand but can extend his wrist. What is the nature of this patients injury?

The median and ulnar nerves are damaged at the wrist.

Trauma both to the median and ulnar nerves at the wrist results in total clawing of the fingers. The metacarpophalangeal joints of all digits are extended by the unopposed extensors because the radial nerve is intact. All interossei and lumbricals are paralyzed because the deep branch of the ulnar nerve supplies all of the interossei; lumbricals I and II are paralyzed, for they are innervated by the median nerve; lumbricals III and IV are paralyzed, for they receive supply from the deep ulnar nerve. The interossei and lumbricals are responsible for extension of the interphalangeal joints. When they are paralyzed, the long flexor tendons pull the fingers into a position of flexion, completing the claw appearance. If the median nerve were intact, the clawing would be less noticeable in the index and long finger because the two lumbricals would still be capable of some degree of extension of those interphalangeal joints. If the median nerve alone is injured in the carpal tunnel, there would be loss of thenar opposition but not clawing. If the median and ulnar nerves are both transected at the elbow, the hand appears totally flat because of the loss of long flexors, in addition to intrinsic paralysis.

A 68-year-old woman fell when she missed the last step from her motor home. Radiographic examination at the local medical care center reveals a fracture of the distal radius. The distal fragment of the radius is angled forward. What name is commonly applied to this type of injury?

Smiths fracture

Colles fracture is a fracture of the distal radius with the distal fragment displaced dorsally. Smiths fracture involves the distal fragment displaced in a volar direction. Smiths fracture is sometimes referred to as a reverse Colles fracture.

It was reported by the sports media that the outstanding 27-year-old shortstop for the New York team would miss a number of baseball games. He was hit on a fingertip while attempting to catch a ball bare-handed. A tendon had been torn. The team doctor commented that the ballplayer could not straighten the last joint of the long finger of his right hand, and the finger would

Mallet finger

The extensor tendons of the fingers insert distally on the distal phalanx of each digit. If the tendon is avulsed, or the proximal part of the distal phalanx is detached, the distal interphalangeal joint is pulled into total flexion by the unopposed flexor digitorum profundus. This result gives the digit the appearance of a mallet. In boutonnière deformity, the central portion of the extensor tendon expansion is torn over the PIP joint, allowing the tendon to move palmarward, causing the tendon to act as a flexor of the PIP joint. This causes the DIP joint to be hyperextended. Swan-neck deformity involves slight flexion of MCP joints, hyperextension of PIP joints, and slight flexion of DIP joints. This condition results most often from shortening of the tendons of intrinsic muscles, as in rheumatoid arthritis. Dupuytren contracture results from connective tissue disorder in the palm, usually causing irreversible flexion of digits 4 and 5. Clawhand occurs with lesions to the median and ulnar nerves at the wrist. In this clinical problem all intrinsic muscles are paralyzed, including the extensors of the interphalangeal joints. The MCP joint extensors, supplied by the radial nerve, and the long flexors of the fingers, supplied more proximally in the forearm by the median and ulnar nerves, are intact and are unopposed, pulling the fingers into the claw appearance.

A 31-year-old female figure skater is examined in the emergency department following an injury that forced her to withdraw from competition. When her male partner missed catching her properly from an overhead position, he grasped her powerfully, but awkwardly, by the forearm. Clinical examination demonstrated a positive Ochsner test, inability to flex the distal interphalangeal joint of the index finger on clasping the hands. In addition, she is unable to flex the terminal phalanx of the thumb and has loss of sensation over the thenar half of the hand. What is the most likely nature of her injury?

Median nerve injured within the cubital fossa

Because the median nerve is injured within the cubital fossa, the long flexors are paralyzed, including the flexor pollicis longus. Flexor pollicis longus would not be paralyzed if the median nerve were injured at the wrist. Lateral palm sensory loss confirms median nerve injury. If only the anterior interosseous nerve were damaged, there would be no cutaneous sensory deficit. The radial nerve supplies wrist extensors, long thumb abductor, and metacarpophalangeal joint extensors. The ulnar nerve does not supply sensation to the lateral palm.

A 19-year-old fell from a cliff when he was hiking in the mountains. He broke his fall by grasping a tree branch, but he suffered injury to the C8-T1 spinal nerve roots. Sensory tests would thereafter confirm the nature of his neurologic injury by the sensory loss in the part of the limb supplied by which of the following?

Medial antebrachial cutaneous nerve

In a lesion of the lower trunk, or the C8 and T1 nerve roots, there is sensory loss on the medial forearm and the medial side of hand (dorsal and ventral). The medial cord is the extension of the lower trunk. The medial cord gives origin to the medial antebrachial cutaneous nerve, which supplies the T1 dermatome of the medial side of the antebrachium. The lower lateral brachial cutaneous nerve arises from the radial nerve, C5 and C6. The musculocutaneous nerve arises from the lateral cord, ending in the lateral antebrachial cutaneous nerve, with C5 and C6 dermatome fibers. The intercostobrachial nerve is the lateral cutaneous branch of the T2 ventral primary ramus and supplies skin on the medial side of the arm. The median nerve distributes C6 and C7 sensory fibers to the lateral part of the palm, thumb, index, long finger, and half of the ring finger.

The mastectomy procedure on a 52-year-old female involved excision of the tumor and a removal of lymph nodes, including the pectoral, central axillary, and infraclavicular groups. Six months after her mastectomy, the patient complains to her personal physician of an unsightly deep hollow area inferior to the medial half of the clavicle, indicating a significant area of muscle atrophy and loss. She states that the disfigurement has taken place quite gradually since her mastectomy. Physical examination reveals no obvious motor or sensory deficits. What was the most likely cause of the patients cosmetic problem?

A branch of the lateral pectoral nerve was cut.

The first branch of the lateral pectoral nerve is typically the only source of motor supply to the clavicular head of the pectoralis major. If it is injured (as in this case of an iatrogenic injury when the infraclavicular nodes were removed), this part of the muscle undergoes atrophy, leaving an infraclavicular cosmetic deficit. The remainder of the lateral pectoral nerve joins the medial pectoral nerve in a neural arch that provides motor supply to the remaining parts of the pectoralis major and the pectoralis minor. Physical examination reveals no obvious motor or sensory deficits. Loss of the medial pectoral nerve would have no effect on the clavicular head of pectoralis major and might not be discernible. Injury to the lateral cord would lead to loss not only of all of the lateral pectoral nerve but also the musculocutaneous nerve, resulting in biceps and brachialis paralysis and lateral antebrachial sensory loss.

A 54-year-old female was found unconscious on the floor, apparently after a fall. She was admitted to the hospital, and during physical examination it was observed that she had absence of her brachioradialis reflex. Which spinal nerve is primarily responsible for this reflex in the majority of cases?

C6

The C6 spinal nerve is primarily responsible for the brachioradialis reflex. C5 and C6 are both involved in the biceps brachii reflex; C5 for motor, C6 for the sensory part of the reflex arc; C7 is the key spinal nerve in the triceps reflex.

A 43-year-old man is admitted to the hospital, having suffered a whiplash injury when his compact auto was struck from behind by a sports utility vehicle. MRI examination reveals some herniation of a disk in the cervical region. Physical examination reveals that the patient has lost elbow extension; there is absence of his triceps reflex and loss of extension of the metacarpophalangeal joints on the ipsilateral side. Which of the following spinal nerves is most likely affected?

C7

C7 is the main spinal nerve that contributes to the radial nerve and innervates the triceps. Absence of the triceps reflex is usually indicative of a C7 radiculopathy or injury.

A 29-year-old patient has a dislocated elbow in which the ulna and medial part of the distal humerus have become separated. What classification of joint is normally formed between these two bones?

Ginglymus

Ginglymus joint is the technical term to describe a hinge joint. It allows motion in one axis (flexion and extension in the case of the elbow) and is therefore a uniaxial joint. The other types of joints listed allow motion in more than one axis.

A 45-year-old woman motorcyclist, propelled over the handlebars of her bike by an encounter with a rut in the road, lands on the point of one shoulder. The woman is taken by ambulance to the emergency department. During physical examination the arm appears swollen, pale, and cool. Any movement of the arm causes severe pain. Radiographic examination reveals a fracture and a large hematoma, leading to diagnosis of Volkmanns ischemic contracture. At which of the following locations has the fracture most likely occurred?

Supracondylar line of humerus

A fracture of the humerus just proximal to the epicondyles is called a supracondylar fracture. This is the most common cause of a Volkmann ischemic fracture. The sharp bony fragment often lacerates the brachial (or other) artery, with bleeding into the flexor compartment. Diminution of arterial supply to the compartment results in the ischemia. Bleeding into the compartment causes greatly increased pressure, first blocking venous outflow from the compartment, then reducing the arterial flow into the compartment. The ischemic muscles then undergo unrelieved contracture. A humeral fracture is sometimes placed in a cast from shoulder to wrist, often concealing the ischemia until major tissue loss occurs. Cold, insensate digits and great pain are warnings of this compartmental problem, demanding that the cast be removed and the compartment opened (released) for pressure reduction and vascular repair. Fracture of the surgical neck endangers the axillary nerve and posterior humeral circumflex artery, although not ischemic contracture. Fracture of the humerus in the spiral groove can injure the radial nerve and profunda brachii artery. Fracture of the olecranon does not result in Volkmanns contracture, although the triceps brachii can displace the distal fractured fragment of the ulna.

A 55-year-old female choreographer had been treated in the emergency department after she fell from the stage into the orchestra pit. Radiographs revealed fracture of the styloid process of the ulna. Disruption of the triangular fibrocartilage complex is suspected. With which of the following bones does the ulna normally articulate at the wrist?

Radius

Normally, the distal part of the ulna articulates only with the radius at the distal radioulnar joint at the wrist, a joint that participates in pronation/supination. The head of the ulna does not articulate with any of the carpal bones; instead, it is separated from the triquetrum and lunate bones by the triangular fibrocartilage complex between it and the radius. The pisiform articulates with the triquetrum. The carpal articulation of the radius is primarily that of the scaphoid (old name is navicular) bone.

A 67-year-old female had a bad fall while walking her dog the evening before. She states that she fell on her outstretched hand. Radiographs do not demonstrate any bony fractures. The clinician observes the following signs of neurologic injury: There is weakness of flexion of her wrist in a medial direction, there is a loss of sensation on the medial side of the hand, and there is clawing of the fingers. Where is the most likely place of nerve trauma?

Behind the medial epicondyle

The force of the womans fall on the outstretched hand was transmitted up through the forearm, sometimes resulting in dislocation of the olecranon at the elbow, putting traction on the ulnar nerve as it passes around the medial epicondyle of the humerus. Ulnar trauma at the elbow can cause weakness in medial flexion (adduction) at the wrist, from loss of the flexor carpi ulnaris. Ulnar nerve injury also results in sensory loss in the medial hand and paralysis of the interossei and medial two lumbricals, with clawing especially of digits 4 and 5. Injury of the ulnar nerve at the pisiform bone would not affect the flexor carpi ulnaris, nor would it produce sensory loss on the dorsum of the hand because the dorsal cutaneous branch of the ulnar branches off proximal to the wrist. Carpal tunnel problems affect median nerve function, which is not indicated here. The ulnar nerve passes medial to the cubital fossa between the heads of the flexor carpi ulnaris, not between the heads of the flexor digitorum superficialis. Injuries at the radial neck affect the site of division of the radial nerve, and its paralysis would not result in the clinical problems seen in this patient.

An 18-year-old male suffered a significant laceration through the skin and underlying tissues at the distal crease of the wrist. The medical student rotating through the emergency department suspected (correctly) that the ulnar nerve was cut completely through at this location. Which of the following would most likely occur?

There would be decreased ability to extend the interphalangeal joints.

The interossei are the most important muscles in extension of the interphalangeal (IP) joints because of the manner of their insertion into the extensor expansion of the fingers, which passes dorsal to the transverse axes of these joints. The lumbrical muscles assist in IP extension, in addition to flexing the metacarpophalangeal joints. Ulnar nerve injury at the wrist results in paralysis of all the interossei and the medial two lumbricals. Extensors of the MCP joints are innervated by the deep radial nerve. Unopposed extension of the MCP joints causes them to be held in extension whereas unopposed long flexors of the fingers (supplied by median and ulnar nerves proximally in the forearm) cause them to be flexed into the claw position. The lumbricals of digits 2 and 3 are still intact because they are supplied by the median nerve, so clawing is not seen as much on these digits. Loss of opposition would result from median or recurrent nerve paralysis. If the ulnar nerve is cut at the wrist, its dorsal cutaneous branch to the dorsum of the hand is unaffected.

A 45-year-old man visits the outpatient clinic after a digit of his left hand was injured when a door was slammed on his hand. A superficial cut on his middle finger has been sutured, but functional deficits are observed in the finger: The proximal interphalangeal joint is pulled into constant flexion, whereas the distal interphalangeal joint is held in a position of hyperextension. What is the most likely diagnosis?

Boutonnière deformity

In boutonnière deformity, the central portion of the extensor tendon expansion is torn over the PIP joint, allowing the tendon to move palmarward, causing the tendon to act as a flexor of the PIP joint. This causes the DIP joint to be hyperextended. The tear in the extensor tendon is said to resemble a buttonhole (boutonnière in French), and the head of the proximal phalanx may stick through the hole.

A 67-year-old housepainter visits the outpatient clinic complaining that his hands are getting progressively worse, becoming more and more painful and losing their function. On physical examination of the hands, there is flexion of the metacarpophalangeal joints, extension of the proximal interphalangeal joints, and slight flexion of the distal interphalangeal joints. What is the most likely diagnosis?

Swan-neck deformity

Swan-neck deformity involves slight flexion of MCP joints, hyperextension of PIP joints, and slight flexion of DIP joints. This condition results most often from shortening of the tendons of intrinsic muscles, as in rheumatoid arthritis. When asked to straighten the injured finger, the patient is unable to do so and the curvature of the finger somewhat resembles the neck of a swan.

Several weeks after surgical dissection of her left axilla for the removal of lymph nodes for staging and treatment of her breast cancer, a 32-year-old woman was told by her general physician that she had winging of her left scapula when she pushed against resistance during her physical examination. She told the physician that she had also experienced difficulty lately in raising her right arm above her head when she was combing her hair. In a subsequent consult visit with her surgeon, she was told that a nerve was accidentally injured during the diagnostic surgical procedure and that this produced her scapular abnormality and inability to raise her arm normally. What was the origin of this nerve?

Roots of the brachial plexus

The long thoracic nerve was injured during the axillary dissection, resulting in paralysis of the serratus anterior. The serratus anterior is important in rotation of the scapula in raising the arm above the level of the shoulder. Its loss results in protrusion of the inferior angle (winging of the scapula), which is more obvious when one pushes against resistance. The long thoracic nerve arises from brachial plexus roots C5, C6, and C7. The upper trunk (C5, C6) supplies rotator and abductor muscles of the shoulder and elbow flexors. The posterior division of the middle trunk contains C7 fibers for distribution to extensor muscles; likewise, the posterior cord supplies extensors of the arm, forearm, and hand. The lateral cord (C5, C6, and C7) gives origin to the lateral pectoral nerve, the musculocutaneous nerve, and the lateral root of the median nerve. There is no sensory loss in the limb in this patient; injury to any of the other nerve elements listed here would be associated with specific dermatome losses.

A 72-year-old man consulted his physician because he had noticed a thickening of the skin at the base of his left ring finger during the preceding 3 months. As he described it, There appears to be some hard tissue that is pulling my little and ring fingers into my palm. On examination of the palms of both hands, localized and firm ridges are observed in the palmar skin that extend from the middle part of the palm to the base of the ring and little fingers. What is the medical term for this sign?

Dupuytren

Dupuytren contracture or deformity is a result of fibromatosis of palmar fascia, resulting in irregular thickening of the fascial attachments to the skin, which causes gradual contraction of the digits, especially digits 4 and 5. In 50% of cases, it is bilateral in occurrence. Ape hand, or flat hand, is a result of loss of the median and ulnar nerves at the elbow, with paralysis of all long flexors of the fingers and all intrinsic hand muscles. Clawhand results from paralysis of interphalangeal joint extension by interossei and lumbricals, innervated primarily by the ulnar nerve. Wrist drop occurs with radial nerve paralysis and loss of the extensors carpi radialis longus and brevis. Mallet finger results from detachment of the extensor mechanism from the distal phalanx of a finger and unopposed flexion of that distal interphalangeal joint.

A 24-year-old female basketball player is admitted to the emergency department after an injury to her shoulder. Radiographic examination reveals a shoulder dislocation. What is the most commonly injured nerve in shoulder dislocations?

Axillary

The axillary nerve is a direct branch of the posterior cord and wraps around the surgical neck of the humerus to innervate the teres minor and the deltoid muscles. With this anatomic arrangement, the axillary nerve is tightly tethered to the proximal humerus. When the head of the humerus is dislocated, it often puts traction on the axillary nerve.

A 45-year-old male is admitted to the hospital with a painful arm after a strongest man in the world contest. Physical examination gives evidence of a rupture of the long tendon of the biceps brachii. Which of the following is the most likely location of the rupture?

Intertubercular groove

The long head of the biceps brachii muscles runs in the intertubercular groove on the proximal humerus as it changes direction and turns medially to attach to the supraglenoid tubercle of the scapula. This change in direction within an osseous structure predisposes the tendon to wear and tear, particularly in people who overuse the biceps muscle. This type of injury presents with a characteristic sign called the Popeye sign.

After the orthopedic surgeon examined the MRI of the shoulder of a 42-year-old female he informed her that the supraspinatus muscle was injured and needed to be repaired surgically. Which of the following is true of the supraspinatus muscle?

It is innervated chiefly by the C5 spinal nerve.

The supraspinatus muscle inserts on the greater tubercle of the humerus and is said to initiate abduction of the arm at the shoulder. It is supplied principally by spinal nerve C5. The subscapularis muscle is the only muscle that inserts on the lesser tubercle. The subscapularis muscle is innervated by the upper and lower subscapular nerves. The teres minor takes origin from the lateral border of the scapula; the teres major takes origin from the region of the inferior angle and the lateral border of the scapula.

A 5-year-old boy is admitted to the emergency department after falling from a tree. The parents are informed by the radiologist that their sons fracture is the most common fracture that occurs in children. Which of the following bones was broken?

Clavicle

During a fall on an outstretched upper limb, the forces are conducted through the hand on up through the bones of the limb in succession. Often these bones do not fracture but rather pass the compressive forces proximally. The appendicular skeleton joins with the axial skeleton at the sternoclavicular joint. The forces are not sufficiently transferred to the sternum, causing the clavicle to absorb the force, resulting in fracture of this sigmoidal-shaped bone.

A 22-year-old woman visits the outpatient clinic with pain in her left upper limb. She has a long history of pain in this limb and difficulty with fine motor tasks of the hand. Physical examination reveals paraesthesia along the medial surface of the forearm and palm and weakness and atrophy of gripping muscles (long flexors) and the intrinsic muscles of the hand. The radial pulse is diminished when her neck is rotated to the ipsilateral side (positive Adson test). What is the most likely diagnosis?

Thoracic outlet syndrome

The patient is suffering from thoracic outlet syndrome, involving neural and vascular elements. This results from any condition that decreases the dimensions of the superior thoracic aperture. It could be a result of a cervical rib, accessory muscles, and/or atypical connective tissue bands at the root of the neck. In this case, symptoms involve the arm, forearm, and hand. Paraesthesia along the medial forearm and hand and atrophy of long flexors and intrinsic muscles point to a possible compression or traction problem of the lower trunk (C8, T1) rather than a lesion of either the median or ulnar nerve. The lateral palm has no sensory problem, which tends to rule out median nerve involvement. Changes in the radial pulse point to vascular compression. Erb-Duchenne paralysis of the upper trunk would affect proximal limb functions, such as arm rotation, abduction, etc. This lesion is on the left side, so the brachiocephalic artery could not be involved because it arises from the right side of the aortic arch; moreover, it would not compress the brachial plexus. Carpal tunnel syndrome would not explain the problems of the forearm and medial hand, or the long flexor atrophy. An isolated medial cord lesion would not explain the atrophy of all long flexors and intrinsic muscles and does not explain the radial pulse characteristics. The ischemic pain in the arm is due to vascular compression.

Physical examination reveals weakness of medial deviation of the wrist (adduction), loss of sensation on the medial side of the hand, and clawing of the fingers. Where is the most likely place of injury?

Compression of a nerve passing between the humeral and ulnar heads of origin of flexor carpi ulnaris

The ulnar nerve enters the forearm by passing between the two heads of the flexor carpi ulnaris and descends between and innervates the flexor carpi ulnaris (for medial wrist deviation) and flexor digitorum profundus (medial half) muscles. Injuring the ulnar nerve results in clawhand. It enters the hand superficial to the flexor retinaculum and lateral to the pisiform bone, where it is vulnerable to damage. The ulnar nerve also enters Guyons canal, but damage to it here would not present with the aforementioned symptoms. The median nerve enters the carpal tunnel and the radial nerve passes deep to the brachioradialis.

A 17-year-old female student of martial arts entered the emergency department with a complaint of pain in her hand. Patient history reveals that she had been breaking concrete blocks with her hand. Examination reveals that the patient has weak abduction and adduction of her fingers but has no difficulty in flexing them. The patient also has decreased sensation over the palmar surfaces of the fourth and fifth digits. Which of the following best describes the nature of her injury?

Injury of the ulnar nerve in Guyons canal

Striking the concrete blocks with the medial side of her hand has injured the ulnar nerve in Guyons canal. This is the triangular tunnel formed by the pisiform bone medially, the flexor retinaculum dorsally, and the deep fascia of the wrist ventrally. This injury would result in loss of sensation to the medial palm and the palmar surface of the medial one and a half digits and motor loss of the hypothenar muscles, the interossei, and the medial two lumbricals. The median nerve is not involved, for the thenar muscles and lateral palmar sensations are intact. The dorsal ulnar nerve arises proximal to the wrist, thus it would not be lost. Carpal dislocation is unlikely. If the lunate bone were dislocated, it would not cause compression of the ulnar nerve at the wrist. There is no indication of fifth metacarpal fracture, the so-called boxers fracture.

A 10-year-old male suffered a dog bite that entered the common flexor synovial sheath of his forearm. He was admitted to the hospital, where the wound was cleaned and dressed and he was treated further with rabies antiserum. Two days later the boy was suffering from an elevated temperature, and his palm and one digit were obviously swollen, causing him to cry with pain. Into which of the digits could the infection spread most easily, following the anatomy of the typical common flexor sheath?

Fifth

The common flexor sheath encloses the long flexor tendons of the fingers. This sheath is usually continuous with the flexor sheath of the little finger, which continues within the palm, having no connection with sheaths of the other digits, which do not extend into the palm.

While sharpening his knife, a 23-year-old male soldier accidentally punctured the ventral side of the fifth digit at the base of the distal phalanx. The wound became infected, and within a few days the infection has spread into the palm, within the sheath of the flexor digitorum profundus tendons. If the infection were left untreated, into which of the following spaces could it most likely spread?

Midpalmar Space

The infectious agent was introduced into the synovial sheath of the long tendons of the little (fifth) finger. Proximally, this sheath runs through the midpalmar space, and inflammatory processes typically rupture into this space unless aggressively treated with the appropriate antibiotics.

A 36-year-old patient is admitted to the emergency department with a dull ache in the shoulder or axilla. During physical examination the pain worsens by activity, and, conversely, rest and elevation relieve the pain. History reveals that the patient was hospitalized the past week and a central venous line was used. What is the most likely diagnosis?

Axillary- subclavian vein thrombosis

Axillary-subclavian vein thrombosis is becoming much more common in recent years because of the extensive use of catheters in cancer patients and other chronic medical conditions. Effort-induced thrombosis is seen with strenuous use of the dominant arm with hyperabduction and external rotation of the arm or backward and downward rotation of the shoulder as in playing cricket, volleyball, or baseball or chopping wood. Because the symptoms of subclavian stenosis are fairly dramatic, most patients present promptly, usually within 24 hours. They complain of a dull ache in the shoulder or axilla, the pain worsened by activity. Conversely, rest and elevation often relieve the pain. Patients with catheter-associated axillary-subclavian deep vein thrombosis report similar symptoms at the arm or shoulder on the side with the indwelling catheter. GAS 722; GA 377

A 22-year-old woman had suffered a severe knife wound to the upper lateral portion of her pectoral region, with entry of the knife at the deltopectoral groove. Pressure applied to the wound had prevented further profuse bleeding. In the emergency department, vascular clamps were applied to the axillary artery, proximal and distal to the site of injurywhich had occurred between the second and third parts of the axillary artery. The vascular surgeon knew there was time to repair the wound of the artery because of the rich collateral pathway provided by the anastomoses between which of the following of arteries?

Suprascapular and circumflex scapular

The injury is at the second part of the axillary artery. The suprascapular artery is a branch of the thyrocervical trunk off the subclavian artery, proximal to the axillary artery. The subscapular artery is the major branch of the third part of the axillary artery, giving of the thorocodorsal and the circumflex scapular. In this case blood would be flowing from the circumflex scapular artery in a retrograde direction into the axillary artery, supplying blood distal to the injury.

In a penetrating wound to the forearm of a 24-year-old male, the median nerve is injured at the entrance of the nerve into the forearm. Which of the following would most likely be apparent when the patients hand is relaxed?

The MCP and IP joints of the second and third digits of the hand will be in a condition of extension.

This proximal injury to the median nerve would paralyze all of the long flexors of the digits, except for the DIP flexors of digits 4 and 5, thereby swinging the balance of power to the muscles that extend the digits, all of which are innervated by the radial nerve. The intrinsic hand muscles can aid in flexion of the MCP joints, and they are innervated by the ulnar nerve. However, they are of insufficient size to compensate for the extensor forces exerted on fingers.

A 55-year-old male firefighter is admitted to the hospital after blunt trauma to his right axilla. Examination reveals winging of the scapula and partial paralysis of the right side of the diaphragm. Which of the following parts of the brachial plexus have been injured?

Roots

The winged scapula results from a lesion of the long thoracic nerve, which supplies the serratus anterior muscle. This muscle is responsible for rotating the scapula upward, which occurs during abduction of the arm above the horizontal. The long thoracic nerve comes off the C5 to C7 roots of the brachial plexus. The diaphragm is supplied by the phrenic nerve, which comes off the spinal nerve roots C3 to C5.

A 69-year-old man has numbness and pain in the middle three digits of his right hand at night. He retired 9 years ago after working as a carpenter for 30 years. He has atrophy of the thenar eminence. Which of the following conditions will be the most likely cause of this atrophy?

Compression of the median nerve in the carpal tunnel

The median nerve supplies sensory innervation to the thumb, index, and middle finger as well as to the lateral half of the ring finger. The median nerve also provides motor innervation to muscles of the thenar eminence. Compression of the median nerve in the carpal tunnel explains these deficits in conjunction with normal functioning of the flexor compartment of the forearm. The ulnar nerve is not implicated in these symptoms. Compression of the brachial plexus could not be attributed to pressure from hypertrophy of the triceps, it is located distal to the plexus. In addition, symptoms would include several upper limb deficits rather than the focal symptoms described in this instance. Osteoarthritis of the cervical spine would also lead to increasing complexity of symptoms.

A 54-year-old woman presents with pain in her right wrist that resulted when she fell forcefully on her outstretched hand. Radiographic studies indicate an anterior dislocation of a carpal bone of the proximal row. Which of the following bones is most commonly dislocated?

Lunate

The lunate bone is the most commonly dislocated bone. Displacement is always anteriorly. Dislocation of the lunate bone can precipitate the signs associated typically with carpal tunnel syndrome.

A 32-year-old male who is an expert target shooter reports pain in his right upper limb and slight tingling and numbness of all digits of the ipsilateral hand. However, the tingling and numbness of the fourth and fifth digits is the most severe. The man states that the problem usually occurs when he is firing his gun with his hand overhead. Radiographic studies reveal the presence of a cervical rib and accessory scalene musculature. Which of the following structures is most likely being compressed?

Lower trunk of brachial plexus

A cervical rib (found at C7) typically causes thoracic outlet syndrome, which is a condition characterized by weak muscle tone in the hand and loss of radial pulse when the upper limb is abducted above the shoulder. The mechanism of injury with the gun being fired overhead suggests a lower trunk injury to the brachial plexus. The axillary artery supplies the shoulder muscles, and there is no loss of function to these muscles. The upper trunk of the brachial plexus also supplies innervation to the shoulder muscles, which are unaffected based on the patients presenting abnormalities. The subclavian artery is located anterior to the brachial plexus until it separates the cords as it passes under the clavicle. The brachiocephalic artery and lower trunk of the brachial plexus is only partially correct; the brachiocephalic artery is not directly associated with the brachial plexus due to its location at the midline of the body behind the sternum.

A 23-year-old woman arrives at the emergency department with a swollen, painful forearm. An MRI examination reveals a compartment syndrome originating at the interosseous membrane between the radius and ulna. Which of the following type of joint will most likely be affected?

Synarthrosis

A synarthrosis joint is a fibrous connection that allows minimal to no movement. In this case, virtually no movement is allowed by the interosseous membrane joint between the radius and ulna. Symphysis joints are permanent fibrocartilaginous fusions between two bones; pubic symphysis is an example. Synchondrosis is a temporary joint made of cartilage that transitions to bone typically after growth completes (i.e., epiphyseal plate). Trochoid joints are pivot joints, and the humeral-radial portion of the elbow joint is an example. Ginglymus joints are hinge joints located at the interphalangeal junctions in the hand and foot (PIPs and DIPs).

While working out with weights, a 28-year-old woman experiences a severe pain in her chest. The pain is referred to the anterior chest wall and radiating to the mandible and her left arm. The woman felt dizzy and after 10 minutes she collapsed and was unconscious. A physician happened to be near the woman and immediately tried to feel her radial pulse. The radial artery lies between two tendons near the wrist, which are useful landmarks. Which of the following is the correct pair of tendons?

Flexor carpi radialis and brachioradialis

The radial pulse is best located on the anterior forearm (antebrachium) just proximal to the wrist joint. At this point the radial artery travels on the distal radius between the flexor carpi radialis and brachioradialis tendons. The palmaris longus tendon travels more medially to the radial artery and above the flexor retinaculum. The flexor pollicis longus tendon is a deeper structure in the antebrachium and is also located medially to the radial artery.

A 59-year-old woman is admitted to the hospital in a state of shock. During physical examination, several lacerations are noted in her forearm and her radial pulse is absent. Where is the most typical place to identify the radial artery immediately after crossing the radiocarpal joint?

At the anatomic snuffbox

The radial artery enters the palm through the anatomic snuffbox. The artery then moves on to pierce through the two heads of the first dorsal interosseous muscle and enter the deep aspect of the palm. The flexor pollicis longus tendon runs on the palmar aspect of the hand and the radial artery runs on the dorsal aspect of the hand before entering the deep aspect of the palm, and therefore the radial artery does not run below this tendon. The radial artery does not run between the first and second interosseous muscle and therefore cannot be used as a landmark to identify the artery. Finally, the artery does not run between the first interosseous muscle and the adductor pollicis longus.

A 69-year-old woman visits the outpatient clinic with a complaint of numbness and tingling of her hand for the past 3 months. Physical examination reveals she has numbness and pain in the lateral three digits of her right hand that are relieved by vigorous shaking of the wrist. In addition, the abductor pollicis brevis, opponens pollicis, and the first two lumbrical muscles are weakened. Sensation was decreased over the lateral palm and the volar aspect of the first three digits. Which of the following nerves is most likely compressed?

Median

The median nerve provides innervation to the flexor compartment of the forearm; cutaneous innervation of the second, third, and fourth digits and palmar and dorsum aspects of the hand; and innervation of four intrinsic hand muscles: first and second lumbricals, abductor pollicis brevis, opponens pollicis, and flexor pollicis brevis. The thenar compartment contains the muscle abductor pollicis brevis, opponens pollicis, and flexor pollicis brevis, and these muscles are innervated by the recurrent branch of the median nerve. The patient has weakening of the first two lumbricals and not simply the thenar muscles, so the median nerve is most likely to be compressed. Another indication that the median nerve is compressed is the vigorous shaking of the wrist. Because the median nerve traverses the carpal tunnel, carpal tunnel compression could lead to this action on part of the patient. The ulnar nerve provides innervation for part of the flexor digitorum profundus and flexor carpi ulnaris. These muscles are not weakened in this patient. The radial nerve provides cutaneous supply to the dorsum of the hand and forearm as well as extensor muscles of the forearm. The posterior interosseous nerve is a branch of the radial nerve and provides innervation of the extensor muscles in the forearm.

A 32-year-old man is admitted to the emergency department after a severe car crash. Radiographic examination reveals multiple fractures of his right upper limb. A surgical procedure is performed and metallic plates are attached to various bony fragments to restore the anatomy. Five months postoperatively the patient visits the outpatient clinic. Upon physical examination the patient can abduct his arm and extend the forearm, but the sensation of the forearm and hand is intact; however, the hand grasp is very weak, and he cannot extend his wrist against gravity. Which of the following nerves was most likely injured during the surgical procedure?

Radial nerve at the distal third of the humerus

Radial nerve at the distal third of the humerus. The patient can extend his forearm, which suggests that the triceps muscle is not weakened. Supination appears to be weak along with hand grasp and wrist drop. This would indicate that part of the radial nerve has been lost below the innervation of the triceps and above the branches to the supinator and extensors in the forearm. However, sensation on the forearm and hand is intact, indicating that the superficial branch of the radial nerve is intact. The superficial branch of the radial nerve divides from the deep radial nerve at the distal third of the humerus. The posterior cord of the brachial plexus is responsible for providing innervation of the axially and radial nerves. This patient does have some radial nerve innervation and no loss of axillary nerve function. The patient does not have weakened adduction of the wrist, indicating that the ulnar nerve is not injured. If both the radial and musculocutaneous nerves are injured, supination would not be possible as the supinator muscle and biceps provide supination of the forearm.

A 52-year-old man is admitted to the emergency department after falling on wet pavement. Radiographic examination reveals fracture of the radius. An MRI study reveals a hematoma between the fractured radius and supinator muscle. Upon physical examination the patient has weakened abduction of the thumb and extension of the metacarpophalangeal joints of the fingers. Which of the following nerves is most likely affected?

Posterior interosseous

The posterior interosseous nerve is an extension of the deep branch of the radial nerve. It is responsible for innervation of several muscles in the extensor compartment of the posterior aspect of the forearm, including extension of the metacarpophalangeal joints. The posterior interosseous nerve courses laterally around the radius and passes between the two heads of the supinator muscle and is thus likely to be compressed by a hematoma between the fractured radius and the supinator muscle. Though the radial nerve gives rise to the posterior interosseous nerve, this answer choice is too vague and would not indicate the precise injured branch of the radial nerve. Both the deep branch of the ulnar nerve and the median nerve traverse the medial and anteromedial aspect of the arm, respectively. These nerves primarily supply the flexor compartment of the arm. The anterior interosseous nerve is a branch of the median nerve and supplies the flexor digitorum profundus, flexor pollicis longus, and the pronator quadratus.

A 34-year-old woman is admitted to the emergency department after a car crash. Radiographic studies show marked edema and hematoma of the arm, but there are no fractures. During physical examination the patient presents with inability to abduct her arm without first establishing lateral momentum of the limb, and inability to flex the elbow and shoulder. Which of the following portions of the brachial plexus is most likely injured?

Superior trunk

The superior trunk of the brachial plexus includes C5 and C6, which give rise to the suprascapular nerve, which innervates the supraspinatus muscle. The supraspinatus muscle is the primary muscle involved in abduction of the arm from 0° to 15°. The deltoid muscle, supplied primarily by C5, abducts the arm from 15 degrees to 90 degrees. The middle trunk is just C7 and has nothing to do with the muscle involved in initial abduction of the arm. The inferior trunk is C8-T1 and does not supply the supraspinatus muscle; therefore, it is not the right answer. The cords are distal to the branching of the supraspinatus muscle; therefore, neither lateral cord nor medial cord is the correct answer.

A 22-year-old man is admitted to the hospital after a car collision. Radiographic examination reveals an oblique fracture of his humerus. Upon physical examination the patient is unable to extend his forearm. The damaged nerve was most likely composed of fibers from which of the following spinal levels?

C5, C6, C7, C8, T1

The radial nerve acts to extend the forearm at the elbow. This nerve is derived from all the roots of the brachial plexus C5 to T1. None of the other answers include all the roots and are therefore incorrect.

A 56-year-old woman is admitted to the hospital after a severe car crash. A large portion of her chest wall needed to be surgically removed and replaced with a musculoosseous scapular graft involving the medial border of the scapula. Which of the following arteries will most likely recompensate the blood supply to the entire scapula?

Suprascapular

The suprascapular artery arises as a major branch of the thyrocervical trunk from the subclavian artery. It has rich anastomoses with the circumflex scapular artery and could provide essential blood supply to the scapula. The dorsal scapular artery would be lost with the graft. None of the other vessels listed is in position to provide adequate supply to the scapula.

A 56-year-old woman visits the emergency department after falling on wet pavement. Radiographic examination reveals osteoporosis and a Colles fracture. Which of the following carpal bones are often fractured or dislocated with a Colles fracture?

Scaphoid and lunate

The scaphoid and lunate carpal bones are in closest articulation with the radius, which is fractured in a Colles fracture; therefore, they would most likely be disrupted or fractured. The other carpal bones listed do not have direct contact with the radius and have a more distal location; therefore, they would not be as likely to be injured with a Colles fracture.

A 3-year-old girl is admitted to the emergency department with severe pain. History taking reveals that the girl was violently lifted by her raised arm by her mother to prevent the girl from walking in front of a moving car. Which of the following is most likely the cause of the pain?

Separation of head of radius from its articulation with ulna and capitulum of humerus

This type of dislocation is common in children and results when the radius is dislocated and slips out from the anular ligament, which holds it in place, articulating with the ulna and the capitulum of the humerus. In adults the anular ligament has a good grip at the radial neck, but in young children the radial head is not fully developed, leading to an indistinct neck. Compression of the median nerve is not likely due to its medial position in the cubital fossa. The radius does not articulate with the trochlea of the humerus; the ulna articulates at this position. The ulna is not likely to be dislocated because it is more stable than the radius, which has only the anular ligament for its support. The radial nerve does not pass behind the medial epicondyle; rather, the ulnar nerve does this, so this is not the correct answer.

A 61-year-old man was hit by a cricket bat in the midhumeral region of his left arm. Physical examination reveals normal elbow motion; however, he could not extend his wrist or his metacarpophalangeal joints and he reported a loss of sensation on a small area of skin on the dorsum of the hand proximal to the first two digits. Radiographic examination reveals a hairline fracture of the shaft of the humerus just distal to its midpoint. Which of the following nerves is most likely injured?

Radial

Injury to the radial nerve can be caused by a blow to the midhumeral region since the nerve winds around the shaft of the humerus. The symptoms described include the loss of wrist and finger extension and a loss of sensation in an area of skin supplied by the radial nerve.

A 34-year-old man is admitted to the hospital after a car collision. Radiographic examination reveals a fracture at his wrist. Physical examination reveals paralysis of the muscles that act to extend the interphalangeal joints. Which of the following nerves is most likely injured?

Ulnar

The ulnar nerve innervates the dorsal and palmar interossei, which act to abduct and adduct the fingers and assist the lumbricals in their actions of flexing the metacarpophalangeal joints and extending the interphalangeal joints. The recurrent branch of the median nerve innervates the thenar muscle group that functions in the movement of the thumb. The radial and musculocutaneous nerves do not innervate any muscles in the hand. The anterior interosseous innervates the flexor pollicis longus and the pronator quadratus.

A 45-year-old woman is admitted to the hospital with neck pain. An MRI examination reveals a herniated disk in the cervical region. Physical examination reveals weak triceps brachii muscles. Which of the following spinal nerves is most likely injured?

C7

The triceps brachii muscle is innervated by the radial nerve (primarily C7), which comes off C5 to T1 spinal nerves. Because the patients only motor deficit involves the triceps brachii muscles, one can rule out C5 and C6, which supply fibers to the axillary, musculocutaneous, and upper subscapular nerves. Damage to either of these roots would result in additional motor deficits of the shoulder and flexor compartment of the arm. One can also rule out C8-T1 because these roots form the medial pectoral nerve and the medial brachial and antebrachial cutaneous nerves. Damage to these roots would result in loss of pectoral muscle function and cutaneous sensation over the medial surface of the upper limb.

A 34-year-old woman is admitted to the hospital after a car collision. Physical examination reveals a mallet finger. Which of the following conditions is expected to be present during radiographic examination?

Avulsion fracture of the dorsum of the distal phalanx

Mallet finger, also known as baseball finger, is a deformity in which the finger will be permanently flexed at the distal interphalangeal joint, due to avulsion of the insertion of the extensor tendon at the distal phalanx.

A 42-year-old woman is admitted to the hospital with injury to the upper (superior) trunk of the brachial plexus. The diagnosis is Erb-Duchenne palsy. Which of the following conditions is expected to be present during physical examination?

Inability to laterally rotate the arm

Injury to the superior trunk of the brachial plexus can damage nerve fibers going to the suprascapular, axillary, and musculocutaneous nerves. Damage to the suprascapular and axillary nerves causes impaired abduction and lateral rotation of the arm. Damage to the musculocutaneous nerve causes impaired flexion of the forearm. A winged scapula would be caused by damage to the long thoracic nerve. The long thoracic nerve is formed from spinal cord levels C5, C6, and C7, so the serratus anterior muscle would be weakened from the damage to C5 and C6, but the muscle would not be completely paralyzed. The intrinsic muscles of the hand are innervated by the ulnar nerve, which would most likely remain intact. Paraesthesia in the medial aspect of the arm would be caused by damage to the medial brachial cutaneous nerve (C8-T1; inferior trunk). Loss of sensation on the dorsum of the hand would be caused by damage to either the ulnar or radial nerves (C6 to T1).

A 41-year-old woman is admitted to the hospital after a car crash. Radiographic examination reveals a transverse fracture of the radius proximal to the attachment of the pronator teres muscle. The proximal portion of the radius is deviated laterally. Which of the following muscles will most likely be responsible for this deviation?

Supinator

The supinator muscle attaches to the radius proximally and when fractured would cause a lateral deviation. The pronator teres originates on the medial epicondyle and coronoid process of the ulna and inserts on the middle of the lateral side of the radius, pulling the radius medially below the fracture. Pronator quadratus originates on the anterior surface of the distal ulna and inserts on the anterior surface of the distal radius, pulling the radius medially. Brachioradialis originates on the lateral supracondylar ridge of the humerus and inserts at the base of the radial styloid process, far below the fracture. Brachialis originates in the lower anterior surface of the humerus and inserts in the coronoid process and ulnar tuberosity, hence not causing an action on the radius.

A 45-year-old woman is bitten by a dog on the lateral side of her hand. Two days later the woman develops fever and swollen lymph nodes. Which of the following group of lymphatics will most likely be involved?

Central

Lymph from the lateral side of the hand drains directly into humeral (epitrochlear) nodes then to the central (axillary) nodes. Pectoral nodes receive lymph mainly from the anterior thoracic wall, including most of the breast. Subscapular nodes receive lymph from the posterior aspect of the thoracic wall and scapular region. Parasternal nodes receive lymph from the lower medial quadrant of the breast.

A 25-year-old woman is admitted to the emergency department after a car collision. Radiographic examination reveals a fracture at the spiral groove of the humerus. A cast is placed, and 3 days later the patient complains of severe pain over the length of her arm. During physical examination the arm appears swollen, pale, and cool. Radial pulse is absent, and any movement of the arm causes severe pain. Which of the following conditions will most likely characterize the findings of the physical examination?

Compartment Syndrome

Compartment syndrome is characterized by increased pressure within a confined space by a fascial compartment, which impairs blood supply, resulting in paleness. Venous thrombosis would not cause pain but could cause death from a pulmonary embolism. Thoracic outlet syndrome affects nerves in the brachial plexus and the subclavian artery and blood vessels between the neck and the axilla, far above the cast. Raynauds disease affects blood flow to the limbs when they are exposed to temperature changes or stress. The fracture at the radial groove probably resulted in a radial nerve injury but would not be responsible for these symptoms.

A 22-year-old woman is admitted to the hospital after falling from a tree. Radiographic examination reveals fractured pisiform and hamate bones. Which of the following nerves will most likely be injured?

Deep Ulnar

The deep branch of the ulnar nerve arises at the level of the pisiform bone and passes between the pisiform and the hook of the hamate, hence the ulnar is the nerve most likely to be injured in this patient. The median nerve enters the forearm between the humeral and ulnar heads of the pronator teres muscle then becomes superficial near the wrist. The recurrent median enters the palm through the carpal tunnel. The radial nerve divides into superficial and deep branches when it enters the cubital fossa.

A 43-year-old man visits the outpatient clinic with a painful shoulder. Physical examination reveals a painful arc syndrome due to supraspinatus tendinopathy. Which of the following conditions will be present during physical examination?

Painful abduction 0° to 15°

The supraspinatus initiates abduction of the arm during the first 15° of abduction; palpation of the tendon during this phase would result in pain from a tendinopathy of the supraspinatus.

A 54-year-old woman is admitted to the hospital after falling from a tree with an outstretched hand. Radiographic examination reveals a wrist dislocation. Which of the following carpal bones will most likely be involved?

Scaphoid-lunate

The hallmark fracture caused by a fall on an outstretched hand is a scaphoid-lunate fracture; the scaphoid and lunate are the two wrist bones most proximal to the styloid process of the radius. All the other wrist bones are less likely to be affected by this injury.

A 62-year-old man is admitted to the emergency department after falling on wet pavement. Radiographic examination reveals a carpometacarpal fracture at the base of the thumb. What is the term applied to the described fracture?

Bennetts fracture

Bennetts fracture is a carpometacarpal fracture at the base of the thumb. Smiths fracture is also called a reverse Colles fracture and is caused when the distal fragment of the radius angles forward. Colles fracture is also called silver fork deformity because the distal fragment is displaced posteriorly. Boxers fractures of the necks of metacarpal bones are fractures to the fingers. A scaphoid fracture would be indicated by pain in the anatomical snuffbox.

A 23-year-old woman is participating in a dry ski-slope competition. The woman is admitted to the emergency department after falling and catching her thumb in the matting. Radiographic and physical examinations reveal rupture of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb. The thumb is extremely painful and an injection of lidocaine is performed. What is the most likely diagnosis in this case?

Gamekeepers thumb

Interestingly, gamekeepers thumb was a term coined because this injury was most commonly associated with Scottish gamekeepers who, it is said, killed small animals such as rabbits by breaking their necks between the ground and the gamekeepers thumb and index finger. The resulting valgus force on the abducted MCP joint caused injury to the ulnar collateral ligament. These days this injury is more commonly seen in skiers who land awkwardly with their hand braced on a ski pole, causing the valgus force on the thumb as is seen in this patient. Whereas the term skier thumb is sometimes used, gamekeepers thumb is still in common usage. Bennett fracture is a fracture at the base of the metacarpal of the thumb. Scaphoid fracture occurs after a fall on an outstretched hand, involving the scaphoid and lunate bone. Colles fracture is also called silver fork deformity because the distal fragment of the radius is displaced posteriorly. Boxers fracture is a fracture of the necks of the second and third (and sometimes the fifth) metacarpals. Smiths fracture is also called a reverse Colles fracture and is caused when the distal radius is fractured and the distal radial fragment is angled forward.

A 54-year-old woman is found unconscious in her car. She is admitted to the hospital, and during physical examination she has absent biceps brachii reflex. What is the spinal level of the afferent component of this reflex?

C6

The biceps brachii reflex involves C5 and C6 spinal nerves. C5 provides the motor component; C6 the afferent side of the reflex arc.

A 54-year-old woman is found unconscious in her bed. She is admitted to the hospital, and during physical examination she has absence of her brachioradialis reflex. The ventral ramus of which spinal nerve is responsible for this reflex?

C6

The brachioradialis reflex is performed by tapping the tendon of the brachioradialis muscle. The reflex involves spinal nerves C5, C6, and C7. The major contribution is from C6

A 55-year-old woman is admitted to the emergency department after a car crash. Physical examination reveals severe pain in the flexor muscles of the forearm; fixed flexion position of the finger; and swelling, cyanosis, and anesthesia of the fingers. Which of the following is the most likely diagnosis?

Volkmanns ischemic contracture

Volkmanns contracture is a flexion deformity of the fingers and sometimes the wrist from an ischemic necrosis of the forearm flexor muscles. Bennetts fracture is a fracture at the base of the metacarpal of the thumb. Scaphoid fracture occurs after a fall on an outstretched hand and involves the scaphoid and lunate bones. Colles fracture is also called silver fork deformity because the distal fragment of the radius is displaced posteriorly. Boxers fracture is a fracture of the necks of the second and third (and sometimes the fifth) metacarpals. Smiths fracture is also called a reverse Colles fracture and is caused when the distal radius is fractured, with the radial fragment angled forward.

A 62-year-old man visits the outpatient clinic with pain in his hand after falling on the outstretched hand. Radiographic examination reveals a fracture of the pisiform bone and hematoma of the surrounding area. Which of the following nerves will most likely be affected?

Deep Ulnar

The ulnar nerve enters the forearm by passing between the two heads of the flexor carpi ulnaris and descends between and innervates the flexor carpi ulnaris and flexor digitorum profundus (medial half) muscles. It enters the hand superficial to the flexor retinaculum and lateral to the pisiform bone, where it is vulnerable to damage and provides the deep ulnar branch. The deep branch of the radial nerve arises proximally in the forearm.

A 32-year-old woman visits the outpatient clinic after injuring her elbow falling from her bicycle. Physical examination reveals a benediction attitude of the hand with the index and long fingers extended and the ring and little fingers flexed. Which of the following is the most likely diagnosis?

Injury to Median Nerve

Benediction attitude of the hand with the index and long fingers straight and the ring and little fingers flexed is caused by an injury to the median nerve. The long flexors of the digits are supplied by the median nerve; the unopposed radial nerve and deep ulnar nerve supply the extensors of the digits 13, causing them to be in the extended position. Digits 4 and 5 are slightly flexed, because the flexors of the PIP joints are supplied by the ulnar nerve.

A 54-year-old man is admitted to the emergency department with severe chest pain. Electrocardiographic evaluation reveals a myocardial infarction. Due to the severity of the infarction, a coronary artery bypass surgery using a radial artery graft is proposed. Which of the following tests should be performed during physical examination prior to the bypass graft operation?

Allen Test

The Allen test involves compression of the radial and ulnar arteries at the wrist with the fingers flexed tightly. Pressure is then released on either vessel successively to determine the degree of supply to the hand by either vessel and the patency of the anastomoses between them. The usefulness of the radial artery for bypass can thereby be assessed. The other tests have nothing to do with the patency of the radial artery.

A 34-year-old man visits the outpatient clinic with a painful upper limb after a fall onto a concrete floor. Physical examination reveals that the patient has weak abduction and adduction of his fingers but has no difficulty in flexing them. The patient also has decreased sensation over the palmar surface of the fourth and fifth fingers. Which of the following diagnoses is most likely?

Injury of the ulnar nerve by a fractured pisiform

The ulnar nerve enters the hand superficial to the flexor retinaculum and lateral to the pisiform bone and innervates all the interossei via the deep branch. These muscles are responsible for adduction and abduction of the fingers. Flexion of the fingers is spared because the flexor digitorum superficialis and most of the flexor digitorum profundus are innervated by the median nerve, which is unaffected by this injury. Had the median nerve been compressed in the carpal tunnel, one would have difficulty with motion of the thumb as a result of a lack of innervation of the thenar muscles. An injury of the radial nerve in the arm will result in extension deficit in the forearm and hand. GAS 744; GA 417

Regarding the glenohumeral joint, the tendons of the following muscles form the musculotendinous (rotator) cuff EXCEPT:

teres major

Rotator Cuff muscles can be recalled by the acronym SITS S = Superaspinatous I = Infraspinatous T = Teres Minor S = Subscapularis. Teres Major is NOT part of the rotator cuff muscles.

A young school teacher displaying symptoms of “wristdrop” would most probably have suffered damage to which of the following nerves at which level?
lesion of the radial nerve at the level of the spiral (radial) groove
lesion of the radial nerve at the level of the spiral (radial) groove
posterior circumflex humeral
Paralysis that impairs flexion of the distal interphalangeal joint of the index finger will also produce all of the following conditions EXCEPT:

complete paralysis of the thumb

adductor pollicis is innervated by ulnar nerve. The opposition of the thumb is facilitated by the median nerve. With this concept, we can infer that the damage to only one nerve will NOT cause a complete paralysis of the thumb.

A shoulder separation (which involves the lateral end of the clavicle sliding onto the superior aspect of the acromion process) would most likely result from damage to the:
coracoclavicular ligament
The clavipectoral fascia is pierced by all of the following structures EXCEPT the:

superior or highest thoracic artery

This is a recall/factual question. Know that the clavicopectoral fascia is pierced by the cephalic vein, the lateral pectralis nerve, thoracoacromial artery, and lymphatic vessel. The only structure that does not pierce is superior or highest thoracic artery.

A 35 year old factory worker is seen in the emergency room with a laceration on the palmar surface of the hand, just distal to the flexor retinaculum, she was unable to move the thumb across the palm to touch the little finger. The structure most likely to have been lacerated is the:

recurrent branch of the median nerve

The opposition of the thumb is innervated by the recurrent branch of the median nerve. Median Recurrent branch comes to the thumb and hooks back (thus called the recurrent branch of the median nerve)

Inability to supinate the forearm could result from an injury to which of the following pairs of nerves?

musculocutaneous and radial

Bicep Brachi – innervated by Musculocutaneous Nerve
Supinator – innervated by Radial Nerve

All of the following muscles are responsible for medial rotation of arm EXCEPT the:
teres minor
If the ulnar nerve is cut at the elbow (Choose the Correct statement):
flexion at the metacarpophalangeal joints of ring and little finger is lost
The axillary sheath is derived from which of the following?
prevertebral layer of deep cervical fascia
If the radial nerve is sectioned in the cubital fossa, all of the following results EXCEPT:
wristdrop
The carpal canal contains all of the following structures EXCEPT the:
ulnar nerve and ulnar artery
The two vessels providing the chief blood supply to the breast are the:
lateral thoracic and internal thoracic arteries
In injuries of the upper trunk of the brachial plexus (Erb-Duchenne paralysis), there is paralysis of the lateral rotators and abductors of the shoulder joint. Which of the following muscles can laterally rotate the arm?
deltoid (spinous or posterior part) and infraspinatus
The two muscles which work together to raise the arm vertically over the head ar the:
serratus anterior and trapezius
The lateral pectoral nerves contain spinal cord components from:
C5, 6, 7
The elbow joint is supplied by all of the following nerves EXCEPT the:
medial antebrachial cutaneous
The annular ligament prevents dislocation of the:
head of the radius from the radial notch of the ulna
All of the following statements are true concerning the intrinsic muscles of the hand Except that the:
flexor pollicis brevis flexes the interphalangeal joint of the thumb
A patient with an intercondylar fracture of the humerus is unable to use the muscle that inserts into the pisiform bone, which of the following nerves is most likely to have been damaged?
ulnar
A motorcyclist lost control of her bike and fell on her right arm severely fracturing the surgical neck of the humerus. Which of the following structures lie in contact with the surgical neck?
axillary nerve and posterior circumflex humeral vessels
To test trapezius muscle paralysis, you would ask the patient to:
shrug the shoulder
Muscles supplied by the posterior interosseous nerve include all of the following EXCEPT the:
extensor carpi radial is longus
All of the following statements are true EXCEPT:
pectoralis minor is attached to the lateral lip of the intertubercular groove of the humerus
A 14-year-old fell off a wall and fractured his right humerus at midshaft. The wrist joint immediately assumed a flexed position that the patient was unable to correct. Extension and supination of the forearm was weakened, but not abolished. Skin sensation over the lateral side of the dorsum of the hand was diminished. Select the one peripheral nerve, which if damaged, could account for the symptoms and signs.
radial nerve

All of the following statements are true EXCEPT that the:

A-axillary nerve innervates the deltoid and teres minor muscles
B-medial and lateral pectoral nerves innervates pectoralis major and pectoralis minor muscles
C-subscapulars is innervated by the upper and lower subscapular nerves
D- teres major passes posterior to the long head of the triceps brachii muscles and receives its innervation from the upper subscapular nerve
E- the suprascapular nerves innervates the supraspinatus and infraspinatus muscles

teres major passes posterior to the long head of the triceps brachii muscles and receives its innervation from the upper subscapular nerve
All of the following statements concerning the flexor digitorum profundus are true EXCEPT:
the lateral part is innervated by the ulnar nerve
A lesion of the median nerve in the distal part of the arm results in all of the following EXCEPT:
weakness of supination
The flexors of the arm include all of the following EXCEPT the:
pectoralis minor
The lymph from the medial quadrants of the breast drain mainly into:
internal thoracic (parasternal) nodes
The digital branches of the median nerve supply the skin of all the following EXCEPT the:
dorsal surface of the distal phalanx of the little finger
The suprascapular nerve contains spinal cord components from:
C5 and C6
The anastomosis around the elbow joint is formed by all of the following vessels. Choose the CORRECT statement:
all of the above are correct statements
All of the following muscles insert into the extensor expansion EXCEPT the:
opponens pollicis
All of the following statements are true EXCEPT
the motor supply to the intrinsic muscles of the hand is derived from the second thoracic segment of the spinal cord
The so-called posterior muscles of the forearm are characterized by each of the following EXCEPT that they:
include adductors of the thumb
Which of the following statements concerning the muscles of the hand is true?
the dorsal interossei assists in flexion of the metacarpophalangeal joints and extension of the interphalangeal joints
An infection in the ulnar bursa could result in necrosis of which of the following tendons?
tendon of the flexor digitorum profundus
A patient with a fracture of the clavicle at the junction of the inner and middle third of the bone exhibits overriding of the medial and lateral fragments, in addition, the arm is rotated medially. Based on your knowledge of gross anatomy, answer the following question. The lateral portion of the fractured clavicle is:
deltoid muscle
All of the following muscles are flexors of the forearm EXCEPT the:

palmaris longus

Flexor of the forearm – 3 B’s and the Pronator Teres

All of the following statements are true EXCEPT the:
median nerve is formed on the medial aspect of the axillary artery
The center for the biceps jerk is in which segment of the spinal cord
C5 and C6
The subglenoid displacement of the head of the humerus damages which of the following nerves?
axillary
The center for the triceps jerk is in which segment of the spinal cord?
C6 and C7
Trauma may tear or rupture one or more of the tendons of the rotator cuff muscles. Which tendon is the most commonly torn part of the rotator cuff, especially in baseball pitchers?
supraspinatus
The most frequent site of mammary tumors:
superolateral (upper outer) quadrant
Select the INCORRECT match:
Muscle: Coracobrachialis Distal Attachment: Middle third of lateral surface of humerus
Following injury to a nerve at the wrist, the thumb is laterally rotated and adducted. The hand has a flattened appearance and is “ape-like”. Which of the following nerves is damaged?
median
A man fell and struck the posterior aspect of his upper arm against a concrete block, considerable bleeding was noted. After treatment in emergency, he was sent in for examination in x-ray. He was found to have a commimuted fracture of the humerus near its surgical neck. It was found on return from X-ray, that bleeding was again occurring. The region was anesthetized, and the vascular damage repaired surgically. The nerve which accompanies the vessel in this region appeared to have undergone a relatively severe compression injury as well. The incision was closed and the humerus stabilized to allow it to heal. Considering the description of the site of the injury, apply your knowledge of anatomy to determine which of the following combinations of nerves and arteries were involved in the injury:
the radial nerve and the deep brachial artery (profunda brachii)
A 24 year old woman presented to her doctor with a four-month history of multiple enlarged lymph nodes around her neck. As part of the investigation done to reach diagnosis, a biopsy (surgical removal) of one of the nodes in the lower posterolateral part of the left side of her neck was done. Following the surgery she noticed that her left shoulder drooped, and she was not able to lift it when shrugging. The most likely cause of her shoulder dysfunction is inadvertent operative damage to:
the left spinal accessory nerve
A homeless and alcoholic 68 year-old man was found in the park sleeping on a bench on a cold winter morning. He was observed in the hospital to have numerous signs and symptoms consistent with various syndromes of the upper limb. It was noted that the patient walks with crutches, he was unable to abduct and laterally rotate his left arm. The most likely muscles involved would be the:
deltoid and teres minor
A homeless and alcoholic 68 year-old man was found in the park sleeping on a bench on a cold winter morning. He was observed in the hospital to have numerous signs and symptoms consistent with various syndromes of the upper limb. It was noted that the patient walks with crutches, he was unable to abduct and laterally rotate his left arm. To medially rotate his left arm, the patient does not need the action of his:
biceps brachii
A homeless and alcoholic 68 year-old man was found in the park sleeping on a bench on a cold winter morning. He was observed in the hospital to have numerous signs and symptoms consistent with various syndromes of the upper limb. It was noted that the patient walks with crutches, he was unable to abduct and laterally rotate his left arm. Last year, the patient had a small bone cancer (osteoma) removed from his intertubercular (bicipital) groove; the most likely affected muscles would be those innervated by the:
musculocutaneous and thoracodorsal nerves
All of the following vessels arise either directly or indirectly from the ulnar artery EXCEPT the:
superior and inferior ulnar collateral arteries
A patient is found to have pus in the medial deep palmar space (midpalmar space). The space is:
a space lying medial to a fibrous septum, attaching the palmar aponeurosis to the third metacarpal bone
Regarding the glenohumeral joint, the tendons of the following muscles form the as culotendinous (rotator) Expect:
teres major
A young school-teacher displaying symptoms of “wristdrop” would most probabiy have suffered damage to which of the following nerves at which level?
lesion of the radial nerve at the level of the spiral, (radial) groove
All of the following arteries are involved in the collateral circulation around the scapula Expect:
posterior circumflex humeral
A shoulder separation (which involves the lateral end of the clavicle sliding onto the superior aspect of the acromion process) would most likely result from damage to the
coracoclavicular ligament
The clavipectoral fascia is pierced by all of the following structures Except:
superior or highest thoracic artery
A-35 year-old factory worker is seen in the emergency room with a laceration on the palmar surface of the hand, just distal to the flexor retinaculum, she was unable to move the thumb across the palm to touch the little finger. The structure most likely to have been lacerated is the:
recurrent branch of the median nerve
All of the following muscles are responsible for medial rotation of arm EXPECT
teres minor
If the radial nerve is sectioned in the cubital fossa, all of the following results Except:
wristdrop
The carpal canal contains all of the following structures Except the:
ulnar nerve and ulnar artery
The two vessels providing the chief blood supply to the breast are the:
superior and internal thoracic arteries
In injuries of the upper trunk of the brachial plexus (Erb-Duchenne paralysis), there is paralysis of the lateral rotators and abductors of the shoulder joint. Which of the following muscles can laterally rotate the arm?
deltoid (spinous or posterior part) and infraspinatus
The two muscles which work together to raise the arm vertically over the head are the:
serratus anterior and trapezius
The lateral pectoral nerves contains spinal cord components from:
C5, 6, 7
The annular ligament prevents dislocation of the:
head of the radius from the radial notch of the ulna
A motorcyclist lost control of her bike and fell on her right arm severely fracturing the surgical neck of the humerus, which of the following structures lie in contact with the surgical neck?
axillary nerve and posterior circumflex humeral vessels
Muscles supplied by the posterior interosseous nerve includes all of the following Except the:
extensor pollicis longus
A 14-year-old fell off a wall and fractured his right humerus at midshaft. The wrist joint immediately assumed a flexed position that the patient was unable to correct. Extension and supination of the forearm was weakened, but not abolished. Skin sensation over the lateral side of the dorsum of the hand was diminished. Selected the one peripheral nerve, which if damaged, could account for the symptoms and signs.
radial nerve
All of the following statements are true Except that the
teres major passes posterior to the long head of the triceps brachii muscles and receives its innervation from the upper subscapular nerve
A lesion of the median nerve in the distal part of the arm results in all of the following Except:
weakness of supination
The anastomosis around the elbow joint is formed by all of the following vessels. Choose the Correct statement:
all of the above are correct statements
A patient with a fracture of the clavicle at the junction of the inner and middle third of the bone exhibits overriding of the medial and lateral fragments.
in addition, the arm is rotated medially. Based on your knowledge of gross anatomy, answer the following question. The lateral portion of the fractured clavicle is displaced downward by the:
deltoid muscle
All of the following muscles are flexors of the forearm Except the:
palmaris longus
The subglenoid displacement of the head of the humerus damages which of the following nerves?
axillary
Trauma may tear or rupture one or more of the tendons of the rotator cuff muscles, which tendon is the most commonly torn part of the rotator cuff, especially in baseball pitchers?
supraspinatus
Select the lncorrect match
Muscle: Coracobrachialis Distal Attachment: Middle third of lateral surface of humerus
Following injury to a nerve at the wrist, the thumb is laterally rotated and adducted. The hand has a flattened appearance and is “ape-like”, which of the following nerves is damaged?
median
A man fell and struck the posterior aspect of his upper arm against a concrete block, considerable bleeding was noted. After treatment in emergency, he was sent on for examination in x-ray. He was found to have a comminuted fracture of the humerus near its surgical neck. It was found on return from x-ray, that bleeding was again occurring. The region was anesthetized, and the vascular damage repaired surgically. The nerve which accompanies the vessel in this region appeared to have undergone a relatively severe compression injury as well. The incision was closed and the humerus stabilized to allow it to heal. Considering the description of the site of. the injury, apply your knowledge of anatomy to determine which of the following combinations of nerves and arteries were involved in the injury:
the radial nerve and the deep brachial artery (profunda brachii)
A-24-year old woman presented to her doctor with a four-month history of multiple enlarged lymph nodes around her neck. As part of the investigation done to reach a diagnosis, a biopsy (surgical removal) of one of the nodes in the lower posterolateral part of the left side of her neck was done. Following the surgery she noticed that her left shoulder drooped, and she was not able to lift it when shrugging. The most likely cause of her shoulder dysfunction is inadvertent operative damage to:
the left spinal accessory nerve
c. the left suprascapular nerVe
A homeless and alcoholic 68 year-old man was found in the park sleeping on a bench on a cold winter morning. He was observed in the hospital to have numerous signs and symptoms consistent with various syndromes of the upper limb. It was noted that the patient walks with crutches, he was unable to abduct and laterally rotate his left arm. The most likely muscles involved would be the:
deltoid and teres minor
A homeless and alcoholic 68 year-old man was found in the park sleeping on a bench on a cold winter morning. He was observed in the hospital to have numerous signs and symptoms consistent with various syndromes of the upper limb. It was noted that the patient walks with crutches, he was unable to abduct and laterally rotate his left arm. Last year, the patient had a small bone cancer (osteoma) removed from his intertuberocular (bicipital) groove; the most likely affected muscles would be those innervated by the:
musculocutaneous and thoracodorsal nerves
All of the following vessels arise either directly or indirectly from the ulnar artery Except the:
superior and inferior ulnar collateral arteries
Which of the following structures passes above the superior transverse scapular ligament?
suprascapular artery
c. dorsal scapular nerve
The axillary nerve:
supplies the deltoid and teres minor muscles
All of the following statements concerning the cubital fossa are true Except that the:
medial border is formed by the flexor carpi radial is
All of the following structures are contained within the axilla EXCEPT the:
dorsal scapular nerve
A patient who has “been walking on crutches” and “sleeping on a bench” for several months, came to the hospital with symptoms of “wrist-drop” and inability to “completely abduct his arm”. The nerves most likely injured were the:
radial and axillary
A motorcyclist lost control of her bike and fell on her right arm severely fracturing the surgical neck of the humerus. Which of the following structures lie in contact with the surgical neck?
posterior circumflex humeral vessels and axillary nerve
The following pairs of muscles are innervated by the same nerve EXCEPT:
teres major and rhomboid minor
The nerve which passes through the quadrangular space of the posterior shoulder innervates which muscle?
Deltoid
As an inexperienced phlebotomist (blood drawer) attempts to insert the needle to draw blood from the median cubital vein, the patient suddenly screams and complains of pain and burning in the middle and thumb side of his palm. The nerve accidentally impaled on the needle was the
median
In the process of escaping from T. rex in Jurassic Park the heroine punctures the skin on the medial side of her wrist on a spiny bush. A few days later, due to the toxin, an infection is seen spreading up the medial side of her arm along the large cutaneous vein extending from the dorsum of her hand to the medial side of her arm. The vein involved is the
basilic
An open arterial anastomosis in the shoulder occurs between the suprascapular artery and which other artery?
Circumflex scapular
In a diving accident that severed the spinal cord below the sixth cervical vertebra, which muscle would be affected?
Latissimus dorsi
The lateral antebrachial cutaneous nerve comes from the:
Musculocutaneous nerve
In withdrawing a blood sample from the median cubital vein the needle passes slightly deep and medial; which nerve might possibly be injured?
Medial antebrachial cutaneous
In old age, the supraspinatus tendon is sometimes ruptured where it blends with the capsule of the shoulder joint. Following this kind of injury one might expect
difficulty in abducting the arm
Following the above injury, which of the movements of the arm at the shoulder would you expect to be totally lost?
abduction
Following the above injury there would most likely be diminished cutaneous sensation over what part of the upper limb?
the top of the shoulder and the lateral side of the arm
The ventral roots of the spinal nerves torn in the above injury contained which of the following component
somatic motor nerve fibers
The vein of choice for withdrawing blood is the:
Median cubital
During a strenuous game of tennis a 55 year old woman complained of severe shoulder pain that forced her to quit the game. During physical examination it was found that she could not initiate abduction of her arm, but if her arm was elevated to 45 degrees from the vertical (at her side) position, she had no trouble fully abducting it. Injury to which muscle was responsible?
supraspinatus
A man is in an auto accident and sustains several injuries, among them are:
back of his head in the occipital area
An elderly patient complains of shoulder pain and has difficulty abducting his arm. Arthroscopy is done in which a dye is injected into the shoulder joint and an X-ray taken. The radiologist notes that the dye has leaked from the shoulder joint into the subacromial bursa. What tendon would need to be ruptured for this to occur?
supraspinatus
A person riding a mountain bike on a rustic trail hits a rut, the fork of the bike breaks and the person is thrown into a tree, severely fracturing the upper end of his humerus. During the repair the surgeon ties off the artery traveling through the quadrangular space to stop the hemorrhage. Which artery did he ligate?
posterior circumflex humeral
After initial examination, a patient is sent to radiology. Radiographs reveal that the portion of the scapula forming the tip or point of the shoulder has been fractured. This bone is the
acromion
Several deficits in muscle function of the right upper limb were noted, including inability to abduct the arm. This was caused by denervation of which muscle?
deltoid
Due to the bleeding, the surgeon ligated (tied off) the suprascapular artery as it crossed the top of the scapula. There was no concern however, as she knew that direct collateral branches of which artery would supply the normal distribution of the suprascapular artery.
circumflex scapular
The patient was unable to retract his scapula because of paralysis of the trapezius and
rhomboids
Would there be loss of cutaneous sensation over the shoulder due to loss of the nerves supplying the C5 dermatome?
Yes
When the C5 spinal nerve was severed were any preganglionic sympathetic fibers cut?
No
The rotator cuff is composed of all of the following muscles except:
teres major
Because of their structure and interconnections, which veins are especially important in the metastatic spread of cancer?
Internal vertebral venous plexus
Neurological testing of a patient reveals no cutaneous sensation on the tip of the index finger. Such a finding would indicate injury to some portion of which nerve?
Median
A sixteen-year-old boy receives a superficial cut on the thumb side of his forearm. The superficial vein most likely affected is the:
Basilic
A sixteen-year-old boy received a superficial cut on the ulnar side of his forearm. The superficial vein most likely affected is the:
Basilic
During insertion of an IV cannula in the median cubital vein, the patient suddenly lost feeling on the radial side of the forearm. What nerve was injured?
Lateral antebrachial cutaneous
Following a gunshot wound to the shoulder, a patient is unable to abduct the arm between 0 and 15 degrees, with reduced lateral rotation of the humerus. What nerve is probably injured?
Suprascapular
After trying to throw a curve ball, a pitcher lost sensation from the tip of the little finger. This indicates injury to which nerve?
Ulnar
While having an IV needle inserted into the cephalic vein of the forearm, the patient suddenly screamed in pain and felt tingling in part of the skin of the forearm supplied by the nerve accompanying the vein. What nerve was injured?
Lateral antebrachial cutaneous
Which muscle is the strongest medial rotator of the arm?
Subscapularis
A man suffers a penetrating wound through the anterior axillary fold, with resulting damage to one of the main terminal branches of the brachial plexus. Among the effects is a significant weakening of flexion of the elbow. One or more other effects to be expected is (are):
Weakening of flexion at the shoulder and loss of cutaneous sensation on the anterolateral surface of the forearm
A person sustains a left brachial plexus injury in an auto accident. After initial recovery the following is observed: 1) the diaphragm functions normally, 2) there is no winging of the scapula, 3) abduction cannot be initiated, but if the arm is helped through the first 45 degrees of abduction, the patient can fully abduct the arm. From this amount of information and your knowledge of the formation of the brachial plexus where would you expect the injury to be:
suprascapular nerve
The cords of the brachial plexus are:
at or below the clavicle, closely related to the axillary artery
A man riding a motorcycle hit a wet spot in the road, lost control, and was thrown from his bike. He landed on the right side of his head and the tip of his shoulder, bending his head sharply to the left and stretching the right side of his neck. Subsequent neurological examination revealed that the roots of the 5th and 6th cervical nerves had been torn away from the spinal cord.
The long thoracic nerve innervates which muscle?
Serratus anterior
Which axillary lymph nodes would not be removed by this procedure?
Apical
Postoperative examination revealed that the medial border and inferior angle of the left scapula became unusually prominent (projected posteriorly) when the arm was carried forward in the sagittal plane, especially if the patient pushed with outstretched arm against heavy resistance (e.g., a wall). What muscle must have been denervated during the axillary dissection?
Serratus anterior
A woman riding a mountain bike on a rough trail hits a rut and is thrown from the bike. Her upper, arm hits a tree, fracturing the humerus just above the insertion of the teres major muscle. Later, during examination, it is noted that she cannot extend her forearm at the elbow or hand at the wrist. Which nerve must have been injured?
Radial
During an industrial accident, a sheet metal worker lacerates the anterior surface of his wrist at the junction of his wrist and hand. Examination reveals no loss of hand function, but the skin on the thumb side of his palm is numb. Branches of which nerve must have been severed?
Median
The muscle running downward and medially from the coracoid process which was partially severed was the:
pectoralis minor
Which space or cavity was opened when the surgeon reflected the muscles
axillary space
The large artery that was severed was the:
axillary
The large nerve bundle lying posterior to the artery which was also severed was the:
posterior cord
You are attending an axillary lymph node dissection in a patient with a melanoma in the upper limb. The surgeon says, “We are going to sample the level II lymph nodes posterior to the pectoralis minor muscle.” Having excelled in anatomy, you realize that she is referring to the anatomical nodes known as
Central Axillary Nodes
In the axilla the pectoralis minor is a landmark, being closely related to all of the following structures except.
Cephalic vein
In a patient with Erb-Duchenne palsy, a nerve arising from the superior trunk of the brachial plexus is nonfunctional. This nerve is the:
Suprascapular
The axillary nerve arises directly from which part of the brachial plexus?
posterior cord
Which of the following is not a direct branch of the axillary artery?
thoracodorsal
While putting metal panels on the roof of a barn, one of the panels slips out of the hands of the man on the roof. During an attempt to catch the panel, a worker below is struck by its sharp edge. The panel hits across the anterior surface of his right arm at mid-length and the impact severs all of the tissue to the bone. When examined in the emergency room it is noted that the patient can only weakly flex his elbow and the lateral side of his forearm is numb. In addition to the muscles, which nerve is injured?
musculocutaneous
While treating the patient (in the preceding question) the doctor observes, “You were fortunate that the panel did not sever the large artery running down the medial side of your arm.” The large artery referred to lies in the neurovascular compartment and supplies most everthing below the elbow; this artery is the
brachial
If the second part of the axillary artery was interrupted, collateral blood flow could pass from branches of the thyrocervical trunk into which artery?
Circumflex scapular
In a fracture of the surgical neck of the humerus, which artery may be injured?
Posterior humeral circumflex
While riding a bike, a patient fell against a tree and fractured the shaft of the humerus at midlength. What nerve may be injured because of its close proximity to the injury?
Radial
Loss of sensation from the tip of the index finger is indicative of injury to which nerve?
Median
In a fracture of the midshaft of the humerus, which artery is most likely to be injured?
Deep (profunda brachii) brachial
Supination of the hand and forearm would be diminished by loss of radial nerve function. But one very powerful supinator would remain intact and unaffected, namely:
Biceps brachii
A worker doing repetitive lifting develops an inflammation in the tendon of origin of the extensor carpi radialis brevis muscle, commonly called “tennis elbow”. The focal point of pain would most likely be near which palpable bony landmark?
Lateral epicondyle of humerus
The anterior interosseous is a branch of which nerve?
Median
In an attempt to commit suicide by slashing the ventral side of the wrist, the two tendons of the flexor digitorum superficialis located most superficially were completely severed. What movement would be affected?
Flexion of the PIP joints of digits 3 and 4Flexion of the PIP joints of digits 3 and 4
What muscle is innervated by branches of both the median and ulnar nerves?
Flexor digitorum profundus
Interruption of the median nerve in the cubital fossa affects what movement(s) of the thumb?
Both
Compression of the median nerve in the carpal tunnel affects which hand muscle(s)?
Flexor pollicis brevis
Structures within the carpal tunnel include the:
Both
A patient is severely limited in extension at the wrist joint after several months in a cast following a Colles fracture. Which joint would be especially important in therapy to regain full extension?
radiocarpal
A middle-aged woman comes to you complaining of pain on the lateral side of her right elbow, so severe that she holds her eating utensils in her left hand to eat. She says that she spent the weekend putting in a new garden plot and that it involved loosening and turning over a large area of grass sods with a garden fork. You find that the region just distal to the lateral epicondyle of her humerus is painful to the touch. There is no sensory loss in her forearm or hand. You suspect a localized tearing of the origin of a muscle producing the equivalent of “tennis elbow.” The muscle most likely involved is the:
brachioradialis
A boy fell onto a sharp object and cut his deep radial nerve as it emerged from the supinator muscle. The artery joining it at this point was also injured. The injured artery is the:
posterior interosseous
While going up for a rebound, a basketball player jams her middle finger against the ball. She experiences severe pain and the trainer notes that she can no longer extend the distal phalanx of the finger. The injury has avulsed (torn away from the bone) which structure from her distal phalanx to produce this condition?
extensor expansion
The tendons on the dorsal side of the wrist are held in place by a thickening of the antebrachial fascia called the:
extensor retinaculum
The function of the posterior interosseous nerve is:
sensory from the wrist joint
Development of “tennis elbow” (lateral epicondylitis) involves the origin of which muscle?
Extensor carpi radialis brevis
In an industrial accident, the artery passing lateral to the pisiform bone is cut. This artery is the
Ulnar
After suffering a gunshot would to the forearm, it was determined that the posterior interosseous nerve was severed. What function was lost?
Sensory from the wrist joint
When falling on an outstretched hand, the most commonly dislocated carpal bone is the
Lunate
If the musculocutaneous nerve is severed at its origin from the brachial plexus, flexion at the elbow is greatly weakened but not abolished. What muscle remains operative and can contribute to flexion?
Brachioradialis
If the tendon of palmaris longus were transected, what movement would be affected?
Flexion of the wrist
What muscle is supplied by both the median and ulnar nerves?
Flexor digitorum profundus
The pulse of the radial artery at the wrist is felt immediately lateral to which tendon?
Flexor carpi radialis
If the medial epicondyle of the humerus is fractured and the nerve passing dorsal to it is injured, which muscle would be most affected?
Flexor carpi ulnaris
The extensor expansion of the ring finger receives tendons from all of the following EXCEPT:
Extensor carpi ulnaris
A girl playing softball cuts the palm of her hand as she scoops up a piece of glass along with the ball. If the only nerve damaged is the recurrent branch of the median nerve, she would lose what movement of the thumb?
Opposition
The main source of blood to the superficial palmar arterial arch is the:
Ulnar artery
What sesamoid bone develops in the tendon of flexor carpi ulnaris and is therefore not a part of the wrist joint?
Pisiform
While watching her boyfriend split wood, a teenager was struck on the back of her carpals by a sharp- edged flying wedge. Her extensor digitorum tendons were exposed, though not severed, indicating that the surrounding synovial sheath had been opened. What other muscle has its tendon surrounded by the same synovial sheath?
Extensor indicis
The signs and symptoms of carpal tunnel syndrome may vary among patients, but they always result from compression of what structure in the carpal canal?
Median Nerve
What muscle tendon is enclosed within its own synovial sheath in the carpal canal?
Flexor pollicis longus
The point of insertion of the flexor digitorum superficialis tendon to the index finger is on the:
Middle phalanx
In order to evaluate the carpometacarpal joint of the thumb, the median nerve must be deadened at the wrist (causing paralysis of the muscles supplied by it distal to the injection) to test the joint. Which movement of the thumb would be most affected by the anesthetic?
Opposite
What arterial vessel accompanies the deep branch of the ulnar nerve across the palm?
Deep palmar arterial arch
The fourth dorsal interosseous muscle is innervated by the
deep branch of the ulnar nerve
A student is rollerblading on the Diag and while trying to avoid a bicyclist falls heavily on his right wrist. After the fall he notes severe pain in the anatomical snuff box. Radiological studies reveal a fracture of the bone deep to the snuff box called the
scaphoid
A person carrying a soft drink in their right hand slipped on some ice and the bottle broke in their hand. A shard (jagged piece) of glass entered the hand and severed all of the tissue from the skin down to the metacarpal bone. The cut extended on the lateral side of the index finger, following the proximal transverse crease, clear to the proximal portion of the head of the second metacarpal bone. It did not extend over the third metacarpal.
The clinical manifestations were as follows:
I The subject could not flex any part of the index finger
II The subject had trouble abducting and adducting the index finger
III The subject had total anesthesia of the palmar side of the index finger and the dorsal side of the distal part of the same digit
IV There was considerable bleeding from severed vessels
Repair proceeded and required six hours of surgery.
Which of the following muscle tendons was NOT involved?
the second palmar interosseous muscle
A person carrying a soft drink in their right hand slipped on some ice and the bottle broke in their hand. A shard (jagged piece) of glass entered the hand and severed all of the tissue from the skin down to the metacarpal bone. The cut extended on the lateral side of the index finger, following the proximal transverse crease, clear to the proximal portion of the head of the second metacarpal bone. It did not extend over the third metacarpal.
The clinical manifestations were as follows:
I The subject could not flex any part of the index finger
II The subject had trouble abducting and adducting the index finger
III The subject had total anesthesia of the palmar side of the index finger and the dorsal side of the distal part of the same digit
IV There was considerable bleeding from severed vessels
Repair proceeded and required six hours of surgery.
Which of the following nerves was most likely cut?
common digital branch of the median nerve
A person carrying a soft drink in their right hand slipped on some ice and the bottle broke in their hand. A shard (jagged piece) of glass entered the hand and severed all of the tissue from the skin down to the metacarpal bone. The cut extended on the lateral side of the index finger, following the proximal transverse crease, clear to the proximal portion of the head of the second metacarpal bone. It did not extend over the third metacarpal.
The clinical manifestations were as follows:
I The subject could not flex any part of the index finger
II The subject had trouble abducting and adducting the index finger
III The subject had total anesthesia of the palmar side of the index finger and the dorsal side of the distal part of the same digit
IV There was considerable bleeding from severed vessels
Repair proceeded and required six hours of surgery.
The excessive bleeding most likely came from which of the following arteries?
radialis indicis artery
Structures within the carpal tunnel include:
Radial bursa
After ramming the point of his shoulder into a practice dummy, a football player suffered a severe shoulder separation. Although this is a dislocation of the acromioclavicular joint, several structures could be torn, including the one that gives the joint its greatest strength and stability, namely the:
Coracoclavicular ligament
While doing arthrography of the shoulder joint it was noted that the contrast material flowed into the subacromial (subdeltoid) bursa, along the tendon of the subscapularis and along the proximal part of the tendon of the long head of the biceps. The finding of contrast in which area was abnormal?
into the subacromial (subdeltoid) bursa
While performing an arthrogram to study an apparent rotator cuff injury, it was noted that the contrast material had spread from the shoulder joint onto the anterior lateral surface of the scapula near the joint. When asked, the first year resident responded that this was due to an anterior tear in the cuff. Having just studied the shoulder joint you respond that the contrast is in is a normal extension of the joint cavity called the
subscapular bursa.
Which muscle contributes to the “rotator cuff”?
Supraspinatus
A patient presented to his physician with chronic shoulder pain. It was noted that when asked to abduct his arm, he initially leaned laterally, and then straightened up. When iodinated contrast was injected into his shoulder joint it was found to be in the subdeltoid bursa as well as in the joint cavity. Which structrure was damaged to produce the shoulder pain?
Supraspinatus muscle
The axis of rotation (pronation/supination) at the distal radioulnar joint is through the:
Styloid process of the ulna
A two year old child will not go to take her nap. Her mother tightly holds her left hand as she leads her to the bedroom. Refusing to go further, the child suddenly attempts to jerk away and then sits down screaming and holding her left elbow. In an attempt to calm her down her mother offers her a cookie, but she cannot suppinate her left hand to receive it. Which joint was dislocated?
the proximal radio-ulnar joint
You are in the emergency room when a student is brought in with a shoulder injury sustained while playing touch football. In comparing the symmetry of his two shoulders, you notice a marked elevation of the distal end of his clavicle with respect to the acromion on the injured side. X-ray exam reveals a grade III shoulder separation. In order for this to have occurred, which ligament must be torn?
coracoclavicular
A 3-year-old child walking hand-in-hand with her father screams in pain as he jerks her quickly up onto the curb to dodge a speeding car. The examining physician calls it a case of “pulled elbow”, a dislocation sometimes seen in young children and caused by:
The head of the radius slipping part way out of the annular ligament
A “pulled elbow” in a young child results when the radial head is dislodged from the
Annular ligament
The shoulder is most often dislocated in which direction?
Anterior
The fibrocartilaginous structure which deepens the shoulder socket is the
Glenoid labrum
The synovial cavity of the glenohumeral joint communicates with the subdeltoid (subacromial) bursa after the rupture of the :
Supraspinatus tendon
The interosseous membrane between the radius and ulna is the uniting structure in a type of fibrous joint classified as a:
Syndesmosis
A patient comes in with gunshot wound and requires surgery in which his thoracoacromial trunk needs to be ligated. Which of the
following arterial branches would maintain normal blood flow?

Superior thoracic

The answer is E. The superior thoracic artery is a direct branch of the axillary artery. The thoracoacromial trunk has four branches: the pectoral, clavicular, acromial, and deltoid.

A 29-year-old man comes in with a stab wound, cannot raise his arm above horizontal, and exhibits a condition known as “winged scapula.” Which of the following structures of the brachial plexus would most likely be damaged?

Roots

The answer is D. Winged scapula is caused by paralysis of the serratus anterior muscle that results from damage to the iong thoracic nerve, which arises from the roots of the brachial plexus (C5-C7).

A 16-year-old patient has weakness flexing the metacarpophalangeal joint of the ring finger and is unable to adduct the same finger. Which of the following muscles is most likely paralyzed?

Palmar interosseous

The answer is E. The dorsal and palmar interosseous and lumbrical muscles can flex the metacarpophalangeal joints and extend the inter phalangeal joints. The palmar interosseous muscles adduct the fingers, while the dorsal interosseous muscles abduct the fingers. The flexor digitorum profundus flexes the distal inlerphalangeai joints,

A 27-year-old patient presents with an inability to draw forward and downward the scapula because of paralysis of the pectoraiis minor. Which of the following would most likely be a cause of his condition?

Fracture of the coracoid process

The answer is C. The pectoralis minor inserts on the coracoid process, originates from the second to the fifth ribs, and is innervated by the medial and lateral pectoral nerves that arise from the medial and lateral cords of the brachial plexus. It depresses the shoulder and forms the anterior wall of the axilla. The pectoralis minor has no attachment on the clavicle.

A 22-year-old patient with a stab wound on the chest injured the intercostobrachial nerve. Which of the following conditions results from the described lesion of the nerve?

Loss of sensory fibers from the second intercostal nerve

The answer is D. The intercostobrachial nerve arises from the laterai cutaneous branch of the second intercostal nerve and pierces the intercostal and serratus anterior muscles. It may communicate with the medial brachial cutaneous nerve, and it supplies skin on the medial side of the arm, It contains no skeletal motor fibers but does contain sympathetic postganglionic fibers, which supply sweat glands.

A 16 year-old boy fell from a motorcycle and his radial nerve was severely damaged be* cause of a fracture of the midshaft of the humerus. Which of the following conditions would most likely result from this accident?
Loss of wrist extension, leading to wrist drop
A patient comes in complaining that she cannot flex her proximal interphaiangeal joints. Which of the following muscles appears to be paralyzed on further examination of her finger?
Flexor digitorum supeificialis
A 21-year-old woman walks in with her shoulder and ami injury after falling from a horseback riding. Examination indicates that she cannot adduct her arm because of paralysis of which of the following muscles?
latissimus dorsi
A 35-year-old man walks in with a stab wound to the most medial side of the proximal portion of the cubital fossa. Which of the following structures would most likely be damaged?
Median nerve
An automobile body shop worker has his middle finger crushed while working on a transmission. Which of the following muscles is most likely to retain functioning?

Palmar interosseous

The answer is C. The extensor digitorum, flexor digitorum profundus, dorsal interosseous, and lumbrical muscles are attached to the middle digit, but no palmar interosseous muscle is attached to the middle digit.

A 14-year-old boy fails on the outstretched hand and has a fracture of the scaphoid bone. The fracture is most likely accompanied by a rupture of which of the following arteries?

Radial artery

The answer is D. The scaphoid bone forms the floor of the anatomic snuffbox, through which the radial artery passes to enter the palm. The radial artery divides into the princeps poll ids arteTy and the deep palmar arch.

A 12-year-old boy walks in; he fell out of a tree and fractured the upper portion of his humerus. Which of the following nerves are intimately related to Ihe humerus and are most likely to be injured by such a fracture?

Radial and axillary

The answer is C. The axillary nerve passes posteriorly around the surgical neck of the humerus and the radial nerve lies in the radial groove of the middle of the shaft of the humerus, The ulnar nerve passes behind the medial epicondyle and the median nerve is vulnerable to injury by supracondylar fracture of the humerus, but they lie close to or in contact with the lower portion of the humerus. The musculocutaneous is not in direct contact with the humerus.

A man injures his wrist on broken glass. Which of the following structures entering the palm superficial to the flexor retinaculum may be damaged?

Ulnar artery and ulnar nerve

The answer is D. Structures entering the palm superficial to the flexor retinaculum include the ulnar nerve, uinar artery, palmaris longus tendon, and palmar cutaneous branch of the median nerve. The median nerve, the flexor pollicis longus, and the flexor digitorum superficialis and profundus run deep to the flexor retinaculum,

A 27-year-old pianist with a known carpal tunnel syndrome experiences difficulty in finger movements. Which of the following intrinsic muscles of her hand is paralyzed?

Lateral two lumbricais and opponens pollicis

The answer is C. The median nerve innervates the abductor pollicis brevis, opponens pollicis, and two lateral lumbricals. The ulnar nerve innervates all interossei (palmar and dorsal), the adductor pollicis, and the two medial lumbricals.

A 31-year-old roofer walks in with tenosynovitis resulting from a deep penetrated wound in the palm by a big nail. Examination indicates that he has an infection in the ulnar bursa. This infection most likely resulted in necrosis of which of the following tendons?

Tendon of the flexor digitorum profundus

The answer is C. The ulnar bursa, or common synovial flexor sheath, contains the tendons of both the flexor digitorum superficialis and profundus muscles. The radial bursa envelops the tendon of the flexor pollicis longus. The tendons of the flexor carpi ulnaris and the palmaris longus are not contained in the ulnar bursa.

An 18-year-old boy involved in an automobile accident presents with arm that cannot abduct. His paralysis is caused by damage to which of the following nerves?

Suprascapular and axillary

The answer is A. The abductors of the arm are the deltoid and supraspinatus muscles, which are innervated by the axillary and suprascapular nerves, respectively. The thoracodorsal nerve supplies the latissimus dorsi, which can adduct, extend, and rotate the arm medially. The upper and lower subscapular nerves supply the subscapularis, and the lower subscapular nerve also supplies the teres major; both of these structures can adduct and rotate the arm medially. The musculocutaneous nerve supplies the flexors of the arm, and the radial nerve supplies the extensors of the arm. The dorsal scapular nerve supplies the levator scapulae and rhomboid muscles; these muscles elevate and adduct the scapula, respectively.

A 17 year-old boy with a stab wound received multiple injuries on the upper part of the arm and required surgery. If the brachial artery were ligaled at its origin, which of Ihe following arteries would supply blood to the profunda brachii artery?

Posterior humeral circumflex

The answer is C. The posterior humeral circumflex artery anastomoses with an ascending branch of the profunda brachii artery, whereas the lateral thoracic and subscapular arteries do not. The superior ulnar collateral and radial recurrent arteries arise inferior to the origin of the profunda brachii artery.

A 23-year-old woman who receives a deep cut of her ring finger by a kitchen knife is unable to move the metacarpophalangeal joint. Which of the following pairs of nerves are damaged?

Ulnar and radial

The answer is D. The metacarpophalangeal joint of the ring finger is flexed by the lumbrical, palmar, and dorsal interosseous muscles, which are innervated by the ulnar nerve. The extensor digitorum, which is innervated by the radial nerve, extends this joint. The musculocutaneous and axillary nerves do not suppJy muscles of the hand. The median nerve supplies the lateral two lumbricals, which can Flex metacarpophalangeal joints of the index and middle fingers.

A 27-year-old baseball player is hit on his forearm by a high-speed bail during the World Series, and the muscles that form the floor of the cubital fossa appear to be torn. Which of the following groups of muscles has lost their functions?

Brachialis and supinator

The answer is B. The brachials and supinator muscles form the floor of the cubital fossa.
The brachioradialis and pronator teres muscles form the lateral and medial boundaries, respectively. The pronator quadratus is attached to the distal ends of the radius and the ulna.

A 23-year-old man complains of numbness on the medial side of the arm following a stab wound in the axilla. On examination, he is diagnosed with an injury of his medial brachial cutaneous nerve. In which of the following structures are the cell bodies of the damaged nei^e involved in numbness located?

Dorsal root ganglion

The answer is B. The medial brachial cutaneous nerve contains sensory {general somatic afferent [GSA]) fibers that have cell bodies in the dorsal root ganglia, and an injury of these GSA fibers causes numbness of the medial side of the arm. It also contains sympathetic postganglionic fibers that have cell bodies in the sympathetic chain ganglia. The anterior horn of the spinal cord contains cell bodies of skeletal motor (general somatic efferent |GSE]) fibers, and the lateral horn contains cell bodies of sympathetic preganglionic fibers. The posterior horn contains cell bodies of interneurons.

A 38-year-old homebuilder was involved in an accident and is unable to supinate his forearm. Which of the following nerves are most likely damaged?

Radial and musculocutaneous

The answer is D. The supinator and biceps brachii muscles, which are innervated by the radial and musculocutaneous nerves, respectively, produce supination of the forearm. This is a question of two muscles that can supinate the forearm.

A 31-ycar-old patient complains of sensory loss over the anterior and posterior surfaces of the medial third of the hand and the medial one and one-half fingers, fie is diagnosed by a physician as having “funny bone” symptoms. Which of the following nerves is injured?

Ulnar

The answer is D. The ulnar nerve supplies sensory fibers to the skin over the palmar and dorsal surfaces of the medial third of the hand and the medial one and one-half fingers. The median nerve innervates the skin of the lateral side of the palm; the palmar side of the lateral three and one-half fingers; and the dorsal side of the index finger, the middle finger, and one-half of the ring finger. The radial nerve innervates the skin of the radial side of the hand and the radial two and one-half digits over the proximal phalanx.

A patient with a deep stab wound in the middle of the forearm has impaired movement of the thumb. Examination indicates a lesion of the anterior interosseous nerve. Which of the following muscles is paralyzed?

Flexor digitorum profundus and pronator quadratus

The answer is C. The anterior interosseous nerve is a branch of the median nerve and supplies the flexor pollicis longus, half of the flexor digitorum profundus, and the pronator quadratus. The median nerve supplies the pronator teres, flexor digitorum superficialis, palmaris longus, and flexor carpi radialis muscles. A muscular branch (the recurrent branch) of
the median nerve innervates the thenar muscles.

A 29-year-old patient comes in; he cannot flex the distal intcrphalangeal joint of the index finger. His physician determines he has nerve damage by the supracondylar fracture.
Which of the following conditions is also a symptom of this nerve damage?

Loss of sensation over the distal part of the second digit

The answer is C. The flexor digitorum profundus muscle flexes the distal interphalangeal (DIP) joints of the index and middle fingers and is innervated by the median nerve, which also supplies sensation over the distal part of the second digit. The same muscle flexes the DIP joints of the ring and little fingers but receives innervation from the ulnar nerve, which also innervates the hypothenar muscles. The median nerve innervates the thenar muscles. The radial nerve innervates the supinator, abductor pollicis longus, and extensor pollicis longus and brevls muscles. The ulnar nerve innervates the adductor pollicis. The musculocutaneous nerve supplies the biceps brachii that can supinate the arm.

A 27-year-old man with cubital tunnel syndrome complains of numbness and tingling in the ring and little finger and back and sides of his hand because of damage to the ulnar nerve in the tunnel at the eibow. Which of the following muscles is most likely to be paralyzed?

Two medial lumbricals

The answer is C. The ulnar nerve innervates the two medial lumbricals. However, the median nerve innervates the two lateral lumbricals, the flexor digitorum superficialis, the oppo-nens pollicis, and the pronator teres muscles.

A secretary comes in to your office complaining of pain in her wrists from typing all day. You determine she likely has carpal tunnel syndrome. Which of the following conditions would help you determine the diagnosis?

Flattened thenar eminence

The answer is C. The carpal tunnel contains the median nerve and the tendons of flexor pollicis longus, flexor digitorum profundus, and flexor digitorum superficialis muscles. Carpal tunnel syndrome results from injury to the median nerve, which supplies the thenar muscle. Thus, injury to this nerve causes the flattened thenar eminence. The middle finger has no attachment for the adductors. The ulnar nerve innervates the medial half of the flexor digitorum profundus muscle, which allows flexion of the distal interphalangeal joints of the ring and little fingers. The ulnar nerve supplies the skin over the medial one and one-half fingers and adductor pollicis muscle.

A man is unable to hold typing paper between his index and middle fingers. Which of the following nerves was likely injured?

Ulnar nerve

The answer is C. To hold typing paper, the index finger is adducted by the palmar interosseous muscle, and the middle finger is abducted by the dorsal interosseous muscle. Both muscles are innervated by the ulnar nerve.

The victim of an automobile accidenl has a destructive injury of the proximal row of carpal bones. Which of the following bones is most likely damaged?

Triquetrum

The answer is D. The proximal row of carpal bones consists of the scaphoid, iunate, tri-quetrum, and pisiform bones, whereas the distal row consists of trapezium, trapezoid, capitate, and hamate bones.

A patient has a torn rotator cuff of the shoulder joint as the result of an automobile accident. Which of the following muscle tendons is intact and has normal function?

Teres major

The answer is C. The rotator cuff consists of the tendons of the supraspjnatus, infraspinatus, subscaptilaris, and teres minor muscles. It stabilizes the shoulder joint by holding the head of the humerus in the glenoid cavity during movement. The teres major inserts on the medial lip of the intertubercular groove of the humerus.

A patient complains of having pain with repeated movements of his thumb (claudication). His physician performs the Alien test and finds an insufficiency of the radial artery. Which of the following conditions would be a result of the radial artery stenosis?

A marked decrease in the blood flow in the piinceps pollicis artery

The answer is D. The radial artery divides into the princeps pollicis artery and the deep palmar arterial arch. Thus, stenosis of the radial artery results in a decreased blood flow in the princeps pollicis artery. The superficial palmar arterial arch is formed primarily by the ulnar artery, which passes superficial to the flexor retinaculum. The extensor compartment of the forearm receives blood from the posterior interosseous artery, which arises from the common interosseous branch of the ulnar artery. However, the radial and radial recurrent arteries supply the brachiora-dialis and the extensor carpi radialis longus and brevis.

A patient bleeding from the shoulder secondary to a knife wound is in fair condition because there is vascular anastomosis around the shoulder. Which of the following arteries is most likely a direct branch of the subclavian artery that is involved in the anastomosis?

Dorsal scapular artery

The answer is A. The dorsal scapular artery arises directly from the third part of the subclavian artery and replaces the deep (descending) branch of the transverse cervical artery. The suprascapular artery is a branch of the thyrocervical trunk of the subclavian artery. The thoracoacromial artery is a short trunk from the first or second part of the axillary artery and has pectoral, clavicular, acromial, and deltoid branches,

A patient with a stab wound receives a laceration of the musculocutaneous nerve. Which of the following conditions is most likely to have occurred?

A patient with a stab wound receives a laceration of the musculocutaneous nerve. Which of the following conditions is most likely to have occurred?

The answer is A. The musculocutaneous nerve contains sympathetic postganglionic fibers that supply sweat glands and blood vessels on the lateral side of the forearm and have cell bodies in the sympathetic chain ganglia. The musculocutaneous nerve does not supply the extensors of the forearm and the brachioradialis. This nerve also supplies tactile sensation on the lateral side of the forearm but not the arm and supplies blood vessels on the lateral side of the forearm but not the hand.

A 20-year-oid man fell from the parallel bar during the Olympic trial. A neurologic examination reveals he has a lesion of the lateral cord of the brachial plexus. Which of the following muscles is most likely weakened by this injury?

Pectoralis major

The answer is E. The pectoralis major is innervated by the lateral and medial pectoral nerves originated from the lateral and medial cords of the brachial plexus, respectively. The subscapu-laris, teres major, latissimus dorsi, and teres minor muscles are innervated by nerves originating from the posterior cord of the brachial plexus.

A 24-year-old carpenter suffers a crush injury of his entire little finger. Which of the following muscles is most likely to be spared?

Dorsal interossei

The answer is D. The dorsal interossei are abductors of the fingers. The little finger has no attachment for the dorsal interosseous muscle because it has its own abductor. Therefore, the dorsal interosseous muscle is not affected. Other muscles arc attached to the little finger; thus, they are injured.

A 7-year-old boy falls from a tree house and is brought to an emergency room of a local hospital. On examination, he has weakness in rotating his arm laterally because of an injury of the axillary nerve. Which of the following conditions is most likely to cause a loss of the axillary nerve function?

Inferior dislocation of the head of the humerus

The answer is D. Inferior dislocation of the head of the humerus may damage the axillary nerve, which arises from the posterior cord of the brachial plexus, runs through the quadrangular space accompanied by the posterior humeral circumflex vessels around the surgical neck of the humerus, and supplies the deltoid and teres minor.

A 49-year-old woman is diagnosed as having a large lump in her right breast. Lymph from the cancerous breast drains primarily into which of the following nodes?

Anterior (pectoral) nodes

The answer is B. Lymph from the breast drains mainly (75%) to the axillary nodes, more specifically to the anterior (pectoral) nodes.

A 17-year-old boy fell from his motorcycle and complains of numbness of the lateral part of the arm. Examination reveals the axillary nerve is severed. Which of the following types of axons is most likely spared?

Preganglionic sympathetic axons

The answer is C. The axillary newe contains no preganglionic sympathetic general visceral efferent (GVF.) fibers, but it contains postganglionic sympathetic GVE fibers. The axillary nerve also contains general somatic afferent (CS.Aj, general somatic efferent (GSR), and general visceral afferent (GVA) fibers.

A construction worker suffers a destructive injury of the structures related to the anatomic snuffbox. Which of the following structures would most likely be damaged?

Radial artery

The answer is E. The radial artery lies on the floor of the anatomic snuffbox. Other structures are not related to the snuffbox. The tendons of the extensor poilicis longus, extensor polti-cis bievis, and abductor poilicis longus muscles form the boundaries of the anatomic snuffbox, The scaphoid and trapezium bones form its floor.

A 54-year-old woman finds a lump in her right breast during an annual mammogram and physical examination. On further examination, she is diagnosed with a malignancy in her upper right quadrant. Cancer cells most li kely metastasize primarily to which of the following groups of lymph nodes?

Pectoral (anterior) nodes

The answer is C. Breast cancer cells spread primarily to the pectoral (anterior) axillary nodes because most lymph (75%) from the upper lateral quadrant of the breast drains specifically to the pectoral nodes. Breast cancer cells also spread to the apical and parasternal nodes. The central axillary nodes receive iymph from lateral and subscapulai nodes.

A 21-year-old man injures his right arm in an automobile accident. Radiographic examination reveals a fracture of the medial epicondyle of the humerus. Which of the following nerves is most likely injured as a result of this accident?

Ulnar

The answer is E. The ulnar nerve runs down the medial aspect of the arm and behind the medial epicondyle in a groove, where it is vulnerable to damage by fracture of the medial epi-condyle. Other nerves are not in contact with the medial epicondyle.

A 21-year-old man injures his right arm in an automobile accident. Radiographic examination reveals a fracture of the medial epicondyle of the humerus. Which of the following muscles is most likely paralyzed as a result of this accident?

Adductor pollicis

The answer is D. The ulnar nerve innervates the adductor poilicis muscle. The radial nerve innervates the abductor poilicis long and extensor poilicis brevis muscles, whereas the median nerve innervates the abductor poilicis brevis and opponens poilicis muscles.

A 21-year-old man injures his right arm in an automobile accident. Radiographic examination reveals a fracture of the medial epicondyle of the humerus. After this injury, the patient is unable to

adduct his index finger

The answer is E. The fingers are adductcd by the palmar interosseous muscles; abduction is performed by the dorsal interosseous muscles. The palmar and dorsal interosseous muscles are innervated by the ulnar nerve. The proximal interphaiangeal joints are flexed by the flexor digito-rum superficialis, which is innervated by the median nerve. However, the distal interphaiangeal joints of the index and middle fingers arc flexed by the flexor digitorum profundus, which is innervated by the median nerve (except the medial half of the muscle, which is innervated by the ulnar nerve). The median nerve supplies sensory innervation on the palmar aspect of the middle finger. The abductor poilicis brevis is innervated by the median nerve, the abductor poilicis longus is innervated by the radial nerve.

A 10-year-ohl boy falls off his bike, has difficulty in moving his shoulder, and is brought to an emergency room. Hh radiogram and angiogram reveal fracture of the surgical neck of his humerus and bleeding from the point of the fracture. Which of the following nerves is most likely injured as a result of this accident?

Axillary

The answer is B. The axillary nerve runs posteriorly around the surgical neck of the humerus and is vulnerable to injury such as fracture of the surgical neck of the humerus or inferior dislocation of the humerus. The other nerves listed are not in contact with the surgical neck of the humerus.

A 10-year-ohl boy falls off his bike, has difficulty in moving his shoulder, and is brought to an emergency room. Hh radiogram and angiogram reveal fracture of the surgical neck of his humerus and bleeding from the point of the fracture. Following this accident, the damaged nerve causes difficulty in abduction, extension, and lateral rotation of his arm. Cell bodies of the injured nerve involving in movement of his arm are located in which of the following structures?

Anterior horn of the spinal cord

The answer is C. The (injured) axillary nerve contains general somatic efferent (GSE) fibers whose ceil bodies are located in the anterior horn of the spinal cord and these GSE fibers supply the deltoid and teres minor muscles. The axillary nerve also contains general somatic afferent (GSA) and general visceral afferent (GVA) fibers whose cell bodies are located in the dorsal root ganglia and sympathetic postganglionic fibers whose cell bodies are located in sympathetic chain ganglia. The lateral horn of the spinal cord between Tl and L2 contains ceil bodies of sympathetic preganglionic fibers. The posterior horn of the spinal cord contains cell bodies of interneurons.

A 10-year-ohl boy falls off his bike, has difficulty in moving his shoulder, and is brought to an emergency room. Hh radiogram and angiogram reveal fracture of the surgical neck of his humerus and bleeding from the point of the fracture. The damaged nerve causes numbness of the lateral side of the arm. Cell bodies of the injured nerve fibers involved in sensory loss are located in which of the following stmcturcs?

Dorsal root ganglia

The answer is D. Axillary nerve contains general somatic efferent (GSE), general somatic afferent (GSA), general visceral afferent (GVA), and sympathetic postganglionic general visceral efferent (GVE) fibcTS. Cell bodies of GSA and GVA fibers are located in the dorsal root ganglia. Cell bodies of GSE fibers are located in the anterior horn of the spinal cord. Cell bodies of sympathetic postganglionic GVE fibers are located in the sympathetic chain ganglia, but cell bodies of sympathetic preganglionic GVk” fibers lie in the lateral horn of the spinal cord.

A 10-year-ohl boy falls off his bike, has difficulty in moving his shoulder, and is brought to an emergency room. Hh radiogram and angiogram reveal fracture of the surgical neck of his humerus and bleeding from the point of the fracture. This accident most likely leads to damage of which of the following arteries?

Posterior humeral circumflex

The answer is C. The posterior humeral circumflex artery accompanies the axillary nerve that passes around the surgical neck of the humerus. None of the other arteries are involved.

A 10-year-ohl boy falls off his bike, has difficulty in moving his shoulder, and is brought to an emergency room. Hh radiogram and angiogram reveal fracture of the surgical neck of his humerus and bleeding from the point of the fracture. Following this accident, the boy has weakness in rotating his arm laterally. Which of the following muscles are paralyzed?
teres minor and deltoid
A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus. Which of the following nerves is most likely damaged?

Radial nerve

The answer is B. The radial nerve runs in the radial groove on the back of the shaft of the humerus with the profunda brachii artery. Axillary nerve passes around the surgical neck of the humerus. The ulnar nerve passes the back of the medial epicondyle. The musculocutaneous and median nerves are not in contact with the bone, but the median nerve can be damaged by supracondylar fracture.

A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus. As a result of this fracture, the patient shows lack of sweating on the back of the arm and forearm. Cell bodies of the damaged nerve fibers involved in sweating are located in which of the following structures?

Sympathetic chain ganglion

The answer is D. The (damaged) radial nerve contains sympathetic postganglionic nerve fibers whose cell bodies are located in the sympathetic chain ganglion. Sympathetic postganglionic fibers supply sweat glands, blood vessels, and hair follicles. The radial nerve also contains general somatic efferent (GSR) fibers whose cell bodies are located in the anterior horn of the spinal cord, and general somatic afferent (GSA) and general visceral afferent (GVA) fibers whose cell bodies are located in the dorsal root ganglion. The lateral horn of the spinal cord between Tl and L2 contains cell bodies of sympathetic preganglionic nerve fibers.

A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus. following this accident, the patient has no cutaneous sensation in which of the following areas?

Area of the anatomic snuffbox

The answer is D. The superficial branch of the radial nerve runs distally to the dorsum of the hand to innervate the radial side of the hand, including the area of the anatomic snuffbox and the radial two and one-half digits over the proximal phalanx. The medial aspect of the arm is innervated by the medial brachial cutaneous nerve, the lateral aspect of the forearm by the lateral antebrachial cutaneous nerve of the musculocutaneous nerve, the palmar aspect of the second and third digits by the median nerve, and the medial one and one-half fingers by the ulnar nerve.

A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus. Which of the following arteries may be damaged?

Profunda brachii artery

The answer is C. The radial nerve accompanies the profunda brachii artery in the radial groove on the posterior aspect of the shaft of the humerus. The posterior humeral circumflex artery accompanies the axillary nerve around the surgical neck of the humerus. Other arteries are not associated with the radial groove of the humerus.

A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus. After this accident, supination is still possible through contraction of which of the following muscles?
Biceps brachii
A 25 year old male was admitted to the ER because he had fallen down a flight of stairs and sustained an injury in the shoulder region. Examination of his upper extremity reveals the limb is in an abnormal position. The arm is rotated medially while the forearm is extended and pronated, also he cannot flex his forearm. These signs would indicate damage to the:
Upper brachial plexus
A 45 year old woman is complaining of numbness and cold sensations in her forearm and hand. The radial pulse is very weak and an arteriogram reveals a blockage in the brachial artery at the midarm level. Continued circulation to the distal limb, although decreased, was accomplished by collateral arterial branches from all of the following EXCEPT the:
Subscapular artery
A 34-year-old man is examined in the prison infir¬mary after sustaining a superficial stab wound to the superolateral aspect of the thoracic wall at the level of the third rib. There is little bleeding and no diffi-culty breathing; however, the medial border of the scapula on the injured side pulls away from the body wall when the arm is raised. In addition, the arm cannot be abducted above the horizontal. Which of the following muscles is paralyzed?
Serratus anterior
A 26-year-old man is stabbed in the left chest during a bar brawl. Several days after he is treated, he returns to the physician complaining of decreased function in his left arm. Physical examination reveals a winged left scapula and an inability to raise his left arm above the horizontal. Which of the following nerves is most likely affected?
Long thoracic
A 24-year-old man presents with pain in his right wrist that resulted when he fell hard on his out-stretched hand. Radiographic studies indicate an anterior dislocation of a proximal row carpal bone that articulates with the most lateral proximal row carpal bone. Which of the following bones was dislo¬cated?
Lunate
A patient has a tiny (0.2 cm), but exquisitely painful, tumor under the nail of her index finger. Local anes¬thetic block to a branch of which of the following nerves would be most likely to provide adequate anesthesia for the surgical removal of the mass?
Median
A football player is examined by the team physician following a shoulder injury during a game. Preliminary x-ray films show an inferior dislocation of the humerus. On further examination, there is weakness in lateral rotation and abduction of the arm. The nerve most likely affected is the:
Axillary
A patient presents to the emergency department after sustaining a laceration of the first web space of his hand in a rock-climbing accident. Which of the following structures is also likely to be injured?
Radial artery
A football player experiences an anterior dislocation of the shoulder. Cutaneous sensation over the lower half of the deltoid muscle is impaired. These findings suggest damage to which of the following nerves?
Axillary
After studying Gross Anatomy for the Subject Boards a first year student left West Basic at 1:00am and was mugged on Jefferson Avenue. During the attack the student held his arm up to protect his head and was knifed on the forearm. Subsequently, while waiting to be seen in the emergency room at MNGH, the student realized that he could no longer adduct his thumb. He immediately concluded that the knife must have directly injured his:
Ulnar Nerve
After studying Gross Anatomy for the Subject Boards a first year student left West Basic at 1:00am and was mugged on Jefferson Avenue. During the attack the student held his arm up to protect his head and was knifed on the forearm. Subsequently, while waiting to be seen in the emergency room at MNGH, the student realized that he could no longer adduct his thumb. To confirm his diagnosis, the student should check for absence of sensation in which part of his hand:
Little Finger (pinkie)
After studying Gross Anatomy for the Subject Boards a first year student left West Basic at 1:00am and was mugged on Jefferson Avenue. During the attack the student held his arm up to protect his head and was knifed on the forearm. Subsequently, while waiting to be seen in the emergency room at MNGH, the student realized that he could no longer adduct his thumb. He also should check for specific signs of:
Claw Hand
While rollerblading to school a third year medical student slipped on some wet pavement and crashed into a building. When he got up from his fall he noticed he could not support his right arm and he had lost feeling on his shoulder. As he slowly made his way to the hospital he reviewed his knowledge of the shoulder joint. He remembered that the rotator cuff muscles associated with supporting the shoulder joint consist of all of the following except:
Deltoid Muscle
A fourth year medical student fell off a ladder while installing a flood light above his garage and put his arm through a garage door window. When he got up from his fall he realized the glass had deeply cut the anterior aspect of his wrist and so he decided to go to the nearest emergency room. During his trip to the ER he studied his wrist and began to make an initial diagnosis. Remembering his training, he initially assumed that the cut had affected all of the muscles in his wrist and he proceeded to examine all of them. Since he was able to flex the distal phalangeal joints of his four medial digits and his thumb, he concluded the following muscles were uninjured:
Two of the above. Both Flexor Digigitorum Profundus and Flexor Pollicus Longus
A fourth year medical student fell off a ladder while installing a flood light above his garage and put his arm through a garage door window. When he got up from his fall he realized the glass had deeply cut the anterior aspect of his wrist and so he decided to go to the nearest emergency room. During his trip to the ER he studied his wrist and began to make an initial diagnosis. Remembering his training, he initially assumed that the cut had affected all of the muscles in his wrist and he proceeded to examine all of them. He then concludes that the following nerve(s) to the muscle(s) must also be intact:
Two of the above. Both the Ulnar and Median Nerves must be intact
A fourth year medical student fell off a ladder while installing a flood light above his garage and put his arm through a garage door window. When he got up from his fall he realized the glass had deeply cut the anterior aspect of his wrist and so he decided to go to the nearest emergency room. During his trip to the ER he studied his wrist and began to make an initial diagnosis. Remembering his training, he initially assumed that the cut had affected all of the muscles in his wrist and he proceeded to examine all of them. On further inspection he notes an inability to flex the proximal interphalengeal joints of his four medial fingers. He concludes from this information that he has injured his:
Flexor Digitorum Superficialis Muscle
Rollerblading to class one morning without her wrist guards on Betty Sue hit a curb and fell onto her outstretched left hand. When she got to school she noted tenderness in her wrist in the area of her anatomical snuff box and was concerned she may have fractured one of the bones in her wrist. The carpal bone forming part of the floor of the anatomical snuff box which is most often fractured is the:
Scaphoid Bone
Rollerblading to class one morning without her wrist guards on Betty Sue hit a curb and fell onto her outstretched left hand. When she got to school she noted tenderness in her wrist in the area of her anatomical snuff box and was concerned she may have fractured one of the bones in her wrist. The medial wall of the anatomical snuff box consists of the tendon from:
Extensor Pollicus Longus
Rollerblading to class one morning without her wrist guards on Betty Sue hit a curb and fell onto her outstretched left hand. When she got to school she noted tenderness in her wrist in the area of her anatomical snuff box and was concerned she may have fractured one of the bones in her wrist. If Betty Sue did fracture one of her carpal bones in the snuff box of the wrist there might be a danger of bone necrosis. The artery traveling through the snuff box and supplying the bones in this area is the:
Radial Artery
A 31-year-old barber complains of numbness and paresthesia on the palmar aspect of his right thumb, second and third fingers, and the radial side of the fourth finger. The dorsal tips of these fingers exhibit the same findings. Thenar atrophy is noted as well as weakness when apposing his thumb to his fifth digit. Tapping over the flexor retinaculum (transverse carpal ligament) and forced flexion of the wrist in a downward direction repro¬duces the symptoms. These findings are most closely related to the compression of the:
median nerve
Which nerve is most likely to be injured by a midshaft fracture of the humerus?
Radial
After falling on her outstretched hand, the patient complains of point tenderness in the space between the tendons of the extensor pollicis longus and the extensor pollicis brevis. Which bone is most likely to be fractured?
Scaphoid
A patient has fallen on her outstretched hand and dislocated a carpal bone. Which bone is most likely to be dislocated?
Lunate
When a dislocation of the glenohumeral joint occurs, through which part of the joint capsule does the humeral head pass?
Inferior
Which nerve is a direct branch of a ventral ramus of the brachial plexus?
Suprascapular nerve
Which nerve is most likely to be damaged by a fracture of the surgical neck of the humerus?
Axillary
All of the following muscles can medially rotate the arm at the shoulder EXCEPT:
infraspinatus
All of the following muscles participate in full abduction of the arm EXCEPT:
teres major
Which nerve is most likely to be injured by a fracture of the medial epicondyle of the humerus?
Ulnar
If a patient has a total lesion of the median nerve within the carpal tunnel, which of the following movements of the thumb is no longer possible?
Opposition
A patient complains of a loss of strength in the thumb, and there is a flattening of the thenar emi¬nence. The nerve that is most likely injured is the:
median
Muscles capable of supinating the forearm are innervated by the:
musculocutaneous and radial nerves
A patient presents with inability to abduct and adduct digits II through V and clawing of the digits that is most prominent in digits IV and V. Which nerve is most likely to be injured?
Ulnar
When a patient flexes the wrist, the hand deviates toward the medial side. Which nerve is most likely to be injured?
Median
Winging of the scapula usually indicates a lesion of the:
long thoracic nerve
Examination of a patient reveals a sensory deficit on the skin of the lateral side of the hand. All of the following nerves can be sites of lesions that result in this sensory deficit EXCEPT:
lower trunk of the brachial plexus
A midshaft fracture of the humerus may result in laceration of the radial nerve. Such an injury can result in all of the following EXCEPT:
an inability to supinate the forearm
A lesion of the upper trunk of the brachial plexus can result in all of the following EXCEPT:
an inability to pronate the forearm
A lesion of the lower trunk of the brachial plexus can result in all of the following EXCEPT:
a sensory deficit on the entire dorsal and palmar surfaces of the hand
Examination of a patient reveals paralysis of the abductor pollicis brevis muscle. All of the following nerves can be sites of lesions that resulted in this paralysis EXCEPT:
anterior interosseous nerve
Nerve fibers in the posterior cord of the brachial plexus innervate all of the following muscles EXCEPT:
infraspinatus
A complete lesion of the upper trunk of the brachial plexus results in damage to nerve fibers found in all of the following nerves EXCEPT:
recurrent branch of the median
Nerves that contain nerve fibers from the C8 and/or T1 spinal cord segments include all of the following EXCEPT:
lateral pectoral
Nerves that contain posterior division nerve fibers include all of the following EXCEPT:
medial pectoral
All of the following statements concerning synovial joints are true EXCEPT that the:
articular cartilage is covered by the synovial membrane
At the wrist, the ulnar pulse is palpable
immediately lateral to the tendon of the flexor carpi ulnaris
At the wrist joint, a bone that articulates with the radius is the
lunate
Which of the following is not true of a lesion of the radial nerve?
it may be caused by a deep laceration on the anteromedial surface of the arm overlying the medial epicondyle of the humerus
An injury to the median nerve proximal to the elbow may result in all of the following findings EXCEPT:
loss of flexion of the forearm at the elbow
All of the following movements can be caused by contraction of the flexor digitorum supeficialis EXCEPT:
flexion of the distal interphalangeal joint
An infection in the synovial sheath of the flexor pollicis longus is most likely to spread to the
flexor synovial sheath of the fifth digit
All of the following muscles are attached to the scapula EXCEPT:
pectoralis major

I/II In regards to AC joint injury, these Grades: Non operative, use Sling, Ice, NSAIDS, 1-2 wks start ROM, progressive strengthening when pain free Sling/ice/NSAIDS In regards to AC joint injury, Grade I/II: Non operative, use these, 1-2 wks start …

TRAPEZIUS MUSCLE *Origin*: base of skull, spinous processes of cervical and thoracic vertebrae *Insertion*: Clavicle; acromion process and scapular spine *Action*: Elevates and depresses scapula, retracts scapula, also rotates scapula *Innervation*: Accessory N. C3 and C4 Blood supply: transverse cervical …

compartments in arm, how formed? anterior and posterior compartments formed by medial and lateral intermuscular septum (pass from outer sleave of humerus to deep fascia) anterior compartment: innervated, contains contains elbow flexors (biceps, brachialis) + coracobrachialis m. contains brachial artery. …

Relational/Transitional Spaces: a. Axilla b. Cubital fossa 2. Relational/transitional spaces. The arm extends from the shoulder to the elbow creating two important transitional spaces. a. Superiorly, the Axilla, covered in the previous lecture, is a pyramidal fat-filed fascia partition through …

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