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Anatomy > BRS Upper Arm > Flashcards

BRS Upper Arm Flashcards

1
Q
  1. A 21-year-old patient has a lesion of the up- per trunk of the brachial plexus (Erb–Duchenne paralysis). Which of the following is the most likely diagnosis?
    (A) Paralysis of the rhomboid major
    (B) Inability to elevate the arm above the
    horizontal
    (C) Arm tending to lie in medial rotation
    (D) Loss of sensation on the medial side of the
    (D) Dorsal interosseous
    (E) Palmar interosseous
A
  1. The answer is C. -Loss of sensation on the medial side of the

A lesion of the upper trunk of the brachial plexus results in a condition called “waiter’s tip hand,” in which the arm tends to lie in medial rotation because of paralysis of lateral rotators and abductors of the arm. The long thoracic nerve, which arises from the root (C5–C7) of the brachial plexus, innervates the serratus anterior muscle that can elevate the arm above the horizontal. The dorsal scapular nerve, which arises from the root (C5), innervates the rhomboid major. The medial side of the arm receives cutaneous innervation from the medial brachial cutaneous nerve of the medial cord. The adductor pollicis is innervated by the ulnar nerve.

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2
Q 
2. A patient comes in with a gunshot wound and requires surgery in which his thoracoac- romial trunk needs to be ligated. Which of the following arterial branches would maintain normal blood flow?
(A) Acromial
(B) Pectoral
(C) Clavicular 
(D) Deltoid 
(E) Superior thoracic
A
  1. The answer is E. -Superior thoracic

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

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3
Q
  1. 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?
    (A) Medial cord
    (B) Posterior cord
    (C) Lower trunk
    (D) Roots
    (E) Upper trunk
A
  1. The answer is D.- Roots

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

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4
Q 
4. A 16-year-old patient has weakness flex- ing the metacarpophalangeal joint of the ring finger and is unable to adduct the same finger. Which of the following muscles is most likely paralyzed?
(A) Flexor digitorum profundus
(B) Extensor digitorum
(C) Lumbrical
(D) Dorsal interosseous
(E) Palmar interosseous
A
  1. The answer is E.

The dorsal and palmar interosseous and lumbrical muscles can flex the meta- carpophalangeal joints and extend the interphalangeal joints. The palmar interosseous muscles adduct the fingers, while the dorsal interosseous muscles abduct the fingers. The flexor digito- rum profundus flexes the distal interphalangeal (DIP) joints.

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5
Q
  1. A 27-year-old patient presents with an in- ability to draw the scapula forward and down- ward because of paralysis of the pectoralis minor. Which of the following would most likely be a
    cause of his condition?

(A) Fracture of the clavicle
(B) Injury to the posterior cord of the brachial plexus
(C) Fracture of the coracoid process
(D) Axillary nerve injury
(E) Defects in the posterior wall of the axilla

A
  1. The answer is C. - Fracture of the coracoid process

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

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6
Q
  1. A 22-year-old patient received a stab wound in the chest that injured the intercostobrachial nerve. Which of the following conditions results from the described lesion of the nerve?
    A) Inability to move the ribs
    b) Loss of tactile sensation on the lateral aspect of the arm
    C) Absence of sweating on the posterior aspect of the arm
    D) Loss of sensory fibers from the second intercostal nerve
    E) Damage to the sympathetic preganglionic fibers.
A
  1. The answer is D.- Loss of sensory fibers from the second intercostal nerve

The intercostobrachial nerve arises from the lateral cutaneous branch of the second intercostal nerve and pierces the intercostal and serratus anterior muscles. It may com- municate 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.

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7
Q
  1. A 16-year-old boy fell from a motorcycle, and his radial nerve was severely damaged because of a fracture of the midshaft of the humerus. Which of the following conditions would most likely result from this accident?
    (A) Loss of wrist extension leading to wrist drop
    (B) Weakness in pronating the forearm
    (C) Sensory loss over the ventral aspect of the
    base of the thumb
    (D) Inability to oppose the thumb
    (E) Inability to abduct the fingers
A
  1. The answer is A.-Loss of wrist extension leading to wrist drop

Injury to the radial nerve results in loss of wrist extension, leading to wrist drop. The median nerve innervates the pronator teres, pronator quadratus, and opponens pol- licis muscles and the skin over the ventral aspect of the thumb. The ulnar nerve innervates the dorsal interosseous muscles, which act to abduct the fingers.

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8
Q
  1. A patient comes in complaining that she cannot flex her proximal interphalangeal joints. Which of the following muscles appear(s) to be paralyzed on further examination of her finger?
(A) Palmar interossei
(B) Dorsal interossei
(C) Flexor digitorum profundus
(D) Flexor digitorum superficialis
(E) Lumbricals
A
  1. The answer is D.- Flexor digitorum superficialis

The flexor digitorum superficialis muscle flexes the proximal interphalangeal joints. The flexor digitorum profundus muscle flexes the DIP joints. The palmar and dorsal interossei and lumbricals can flex metacarpophalangeal joints and extend the interphalangeal joints. The palmar interossei adduct the fingers, and the dorsal interossei abduct the fingers.

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9
Q 
9. A 21-year-old woman walks in with a shoul- der and arm injury after falling during horse- back riding. Examination indicates that she cannot adduct her arm because of paralysis of which of the following muscles?
(A) Teres minor
(B) Supraspinatus
(C) Latissimus dorsi
(D) Infraspinatus
(E) Serratus anterior
A
  1. The answer is C-Latissimus dorsi

The latissimus dorsi adducts the arm, and the supraspinatus muscle abducts the arm. The infraspinatus and the teres minor rotate the arm laterally. The serratus anterior rotates the glenoid cavity of the scapula upward, abducts the arm, and elevates it above a hori- zontal position.

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10
Q
  1. A 35-year-old man walks in with a stab wound to the most medial side of the proxi- mal portion of the cubital fossa. Which of the following structures would most likely be damaged?
(A) Biceps brachii tendon
(B) Radial nerve
(C) Brachial artery
(D) Radial recurrent artery
(E) Median nerve
A
  1. The answer is E- Median nerve

The contents of the cubital fossa from medial to lateral side are the median nerve, the brachial artery, the biceps brachii tendon, and the radial nerve. Thus, the median nerve is damaged. The radial recurrent artery ascends medial to the radial nerve.

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11
Q
  1. The police bring in a murder suspect who has been in a gunfight with a police officer. The suspect was struck by a bullet in the arm; his median nerve has been damaged. Which of the following symptoms is likely produced by this nerve damage?
    (A) Waiter’s tip hand
    (B) Claw hand
    (C) Wrist drop
    (D) Ape hand
    (E) Flattening of the hypothenar eminence
A
  1. The answer is D-Ape hand

Injury to the median nerve produces the ape hand (a hand with the thumb permanently extended). Injury to the radial nerve results in loss of wrist extension, leading to wrist drop. Damage to the upper trunk of the brachial plexus produces waiter’s tip hand. A claw hand and flattening of the hypothenar eminence or atrophy of the hypothenar muscles result
from damage to the ulnar nerve.

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12
Q 
12. 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 function?
(A) Extensor digitorum
(B) Flexor digitorum profundus
(C) Palmar interosseous
(D) Dorsal interosseous
(E) Lumbrical
A
  1. The answer is C- Palmar interosseous

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.

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13
Q
  1. A 14-year-old boy falls on his 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?
    (A) Brachial artery
    (B) Ulnar artery
    (C) Deep palmar arterial arch (D) Radial artery
    (E) Princeps pollicis artery
A
  1. The answer is D-Radial artery

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 pollicis artery and the deep palmar arch.

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14
Q
  1. 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 the humerus and are most likely to be injured by such a fracture?
    (A) Axillary and musculocutaneous
    (B) Radial and ulnar
    (C) Radial and axillary
    (D) Median and musculocutaneous
    (E) Median and ulnar
A
  1. The answer is C- Radial and axillary

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 these nerves lie close to or in contact with the lower portion of the humerus. The musculocutaneous nerve is not in direct contact with the humerus.

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15
Q 
15. A man injures his wrist on broken glass. Which of the following structures entering the palm superficial to the flexor retinaculum may be damaged?
(A) Ulnar nerve and median nerve
(B) Median nerve and flexor digitorum
profundus
(C) Median nerve and flexor pollicis longus
(D) Ulnar artery and ulnar nerve
(E) Ulnar nerve and flexor digitorum
superficialis
A
  1. The answer is D-Ulnar artery and ulnar nerve

Structures entering the palm superficial to the flexor retinaculum include the ulnar nerve, ulnar 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.

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16
Q
  1. A patient with Bennett fracture (a fracture of the base of the first metacarpal bone) experi- ences an impaired thumb movement. Which of the following intrinsic muscles of the thumb is most likely injured?
    (A) Abductor pollicis brevis
    (B) Flexor pollicis brevis (superficial head)
    (C) Opponens pollicis
    (D) Adductor pollicis
    (E) Flexor pollicis brevis (deep head)
A
  1. The answer is C-Opponens pollicis

The opponens pollicis inserts on the first metacarpal. All other intrinsic muscles of the thumb, including the abductor pollicis brevis, the flexor pollicis brevis, and the adductor pollicis muscles, insert on the proximal phalanges.

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17
Q
  1. 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?
    (A) Palmar interossei and adductor pollicis
    (B) Dorsal interossei and lateral two
    lumbricals
    (C) Lateral two lumbricals and opponens pollicis
    (D) Abductor pollicis brevis and palmar interossei
    (E) Medial two and lateral two lumbricals
A
  1. The answer is C- Lateral two lumbricals and opponens pollicis

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.

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18
Q
  1. A 31-year-old roofer walks in with tenosy- novitis 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?
    (A) Tendon of the flexor carpi ulnaris
    (B) Tendon of the flexor pollicis longus
    (C) Tendon of the flexor digitorum profundus
    (D) Tendon of the flexor carpi radialis
    (E) Tendon of the palmaris longus
A
  1. The answer is C-Tendon of the flexor digitorum profundus

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 lon- gus are not contained in the ulnar bursa.

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19
Q 
19. An 18-year-old boy involved in an automo- bile accident presents with an arm that cannot abduct. His paralysis is caused by damage to which of the following nerves?
(A) Suprascapular and axillary
(B) Thoracodorsal and upper subscapular
(C) Axillary and musculocutaneous
(D) Radial and lower subscapular
(E) Suprascapular and dorsal scapular
A
  1. The answer is A-Suprascapular and axillary

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.

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20
Q 
20. A 17-year-old boy with a stab wound re- ceived multiple injuries on the upper part of the arm and required surgery. If the brachial artery were ligated at its origin, which of the following arteries would supply blood to the profunda brachii artery?
(A) Lateral thoracic
(B) Subscapular
(C) Posterior humeral circumflex
(D) Superior ulnar collateral
(E) Radial recurrent
A
  1. The answer is C-Posterior humeral circumflex

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.

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21
Q 
21. A 23-year-old woman who receives a deep cut to her ring finger by a kitchen knife is un- able to move the metacarpophalangeal joint. Which of the following pairs of nerves was damaged?
(A) Median and ulnar
(B) Radial and median
(C) Musculocutaneous and ulnar
(D) Ulnar and radial
(E) Radial and axillary
A
  1. The answer is D- Ulnar and radial

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 supply muscles of the hand. The median nerve supplies the lateral two lumbricals, which can flex metacarpophalangeal joints of the index and middle fingers.

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22
Q 
22. A 27-year-old baseball player is hit on his forearm by a high-speed ball 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 have lost their
functions?
(A) Brachioradialis and supinator
(B) Brachialis and supinator
(C) Pronator teres and supinator
(D) Supinator and pronator quadratus
(E) Brachialis and pronator teres
A
  1. The answer is B- Brachialis and supinator

The brachialis and supinator muscles form the floor of the cubital fossa. The brachioradialis and pronator teres muscles form the lateral and medial boundaries, respec- tively. The pronator quadratus is attached to the distal ends of the radius and the ulna.

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23
Q
  1. A 23-year-old man complains of numb- ness 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 nerve involved in numbness located?
    (A) Sympathetic chain ganglion
    (B) Dorsal root ganglion
    (C) Anterior horn of the spinal cord (D) Lateral horn of the spinal cord (E) Posterior horn of the spinal cord
A
  1. The answer is B- Dorsal root ganglion

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.

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24
Q 
24. A 38-year-old homebuilder was involved in an accident and is unable to supinate his fore- arm. Which of the following nerves are most likely damaged?
(A) Suprascapular and axillary
(B) Musculocutaneous and median
(C) Axillary and radial
(D) Radial and musculocutaneous
(E) Median and ulnar
A
  1. The answer is D- Radial and musculocutaneous

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

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25
Q
  1. A 31-year-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. He is diagnosed by a physician as having “funny bone” symptoms. Which of the following nerves is injured?
    (A) Axillary
    (B) Radial
    (C) Median
    (D) Ulnar
    (E) Musculocutaneou
A
  1. The answer is D- Ulnar

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.

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26
Q
  1. 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?
    (A) Flexor pollicis longus and brevis
    (B) Flexor pollicis longus and opponens
    pollicis
    (C) Flexor digitorum profundus and pronator quadratus
    (D) Flexor digitorum profundus and superficialis
    (E) Flexor pollicis brevis and pronator quadratus
A
  1. The answer is C-Flexor digitorum profundus and pronator quadratus

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.

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27
Q
  1. A 29-year-old patient comes in; he cannot flex the distal interphalangeal (DIP) joint of the index finger. His physician determines that he has nerve damage from a supracondylar fracture. Which of the following conditions is also a symptom of this nerve damage?
    (A) Inability to flex the DIP joint of the ring finger
    (B) Atrophy of the hypothenar eminence
    (C) Loss of sensation over the distal part of the second digit
    (D) Paralysis of all the thumb muscles
    (E) Loss of supination
A
  1. The answer is C- Loss of sensation over the distal part of the second digit

The flexor digitorum profundus muscle flexes the 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 brevis muscles. The ulnar nerve innervates the adductor pollicis. The musculocutaneous nerve supplies the biceps brachii that can supinate the arm.

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28
Q 
28. A 27-year-old man with cubital tunnel syn- drome complains of numbness and tingling in the ring and little finger and back and sides of his hand because of damage to a nerve in the tunnel at the elbow. Which of the following muscles is most likely to be paralyzed?
(A) Flexor digitorum superficialis
(B) Opponens pollicis
(C) Two medial lumbricals
(D) Pronator teres
(E) Supinator
A
  1. The answer is C-Two medial lumbricals

The ulnar nerve innervates the two medial lumbricals. However, the median nerve innervates the two lateral lumbricals, the flexor digitorum superficialis, the opponens pollicis, and the pronator teres muscles.

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29
Q
  1. A secretary comes in to your office com- plaining of pain in her wrists from typing all day. You determine that she likely has carpal tunnel syndrome. Which of the following condi- tions would help you determine the diagnosis?
    (A) Inability to adduct the little finger
    (B) Inability to flex the DIP joint of the ring
    finger
    (C) Flattened thenar eminence
    (D) Loss of skin sensation of the medial one
    and one-half fingers
    (E) Atrophied adductor pollicis muscle
A
  1. The answer is C- Flattened thenar eminence

The carpal tunnel contains the median nerve and the tendons of flexor pol- licis longus, flexor digitorum profundus, and flexor digitorum superficialis muscles. Carpal tun- nel 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 DIP joints of the ring and little fingers. The ulnar nerve sup- plies the skin over the medial one and one-half fingers and adductor pollicis muscle.

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30
Q 
30. A man is unable to hold typing paper be- tween his index and middle fingers. Which of the following nerves was likely injured?
(A) Radial nerve
(B) Median nerve
(C) Ulnar nerve
(D) Musculocutaneous nerve
(E) Axillary nerve
A
  1. The answer is C- Ulnar nerve

To hold a typing paper, the index finger is adducted by the palmar interosse- ous muscle, and the middle finger is abducted by the dorsal interosseous muscle. Both muscles are innervated by the ulnar nerve.

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31
Q 
31. The victim of an automobile accident has a destructive injury of the proximal row of carpal bones. Which of the following bones is most likely damaged?
(A) Capitate
(B) Hamate
(C) Trapezium
(D) Triquetrum
(E) Trapezoid
A
  1. The answer is D-Triquetrum
    The proximal row of carpal bones consists of the scaphoid, lunate, trique- trum, and pisiform bones, whereas the distal row consists of the trapezium, trapezoid, capitate, and hamate bones.
32
Q 
32. 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?
(A) Supraspinatus
(B) Subscapularis
(C) Teres major
(D) Teres minor
(E) Infraspinatus
A
  1. The answer is C-Teres major

The rotator cuff consists of the tendons of the supraspinatus, infraspinatus, subscapularis, 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.

33
Q
  1. A patient complains of having pain with re- peated movements of his thumb (claudication). His physician performs the Allen test and finds an insufficiency of the radial artery. Which of the following conditions would be a result of the radial artery stenosis?
    (A) A marked decrease in the blood flow in the superficial palmar arterial arch
    (B) Decreased pulsation in the artery passing superficial to the flexor retinaculum
    (C) Ischemia of the entire extensor muscles of the forearm
    (D) A marked decrease in the blood flow in the princeps pollicis artery
    (E) A low blood pressure in the anterior inter- osseous artery
A

The answer is D- A marked decrease in the blood flow in the princeps pollicis artery

The radial artery divides into the princeps pollicis artery and the deep pal- mar 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 brachioradialis and the extensor carpi radialis longus and brevis.

34
Q
  1. A patient bleeding from the shoulder sec- ondary 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?
    (A) Dorsal scapular artery
    (B) Thoracoacromial artery
    (C) Circumflex scapular artery (D) Transverse cervical artery
    (E) Suprascapular artery
A

The answer is A- Dorsal scapular artery
The dorsal scapular artery arises directly from the third part of the subcla- vian artery and replaces the deep (descending) branch of the transverse cervical artery. The suprascapular and transverse cervical arteries are branches 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.

35
Q
  1. During a breast examination of a 56-year- old woman, the physician found a palpable mass in her breast. Which of the following characteristics of breast cancer and its diagnosis is correct?
    (A) Elevated nipple
    (B) Polymastia
    (C) Shortening of the clavipectoral fascia
    (D) Dimpling of the overlying skin
    (E) Enlargement of the breast
A

The answer is D- Dimpling of the overlying skin

Breast cancer may cause dimpling of the overlying skin because of shortening of the suspensory (Cooper) ligaments and inverted or retracted nipple because of pulling on the lactiferous ducts. Polymastia is a condition in which more than two breasts are present.

36
Q
  1. A patient with a stab wound receives a lac- eration of the musculocutaneous nerve. Which of the following conditions is most likely to have occurred?
    (A) Lack of sweating on the lateral side of the forearm
    (B) Inability to extend the forearm
    (C) Paralysis of brachioradialis muscle
    (D) Loss of tactile sensation on the arm
    (E) Constriction of blood vessels on the hand
A

The answer is A-Lack of sweating on the lateral side of the forearm

The musculocutaneous nerve contains sympathetic postganglionic fibers that supply sweat glands and blood vessels on the lateral side of the forearm as the lateral ante- brachial cutaneous nerve. 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.

37
Q 
37. A 20-year-old man fell from the parallel bar during the Olympic trial. A neurologic examination reveals that he has a lesion of the lateral cord of the brachial plexus. Which of the following muscles is most likely weakened by this injury?
(A) Subscapularis
(B) Teres major
(C) Latissimus dorsi
(D) Teres minor
(E) Pectoralis major
A

The answer is E- Pectoralis major

The pectoralis major is innervated by the lateral and medial pectoral nerves originating 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.

38
Q 
38. 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?
(A) Flexor digitorum profundus
(B) Extensor digitorum
(C) Palmar interossei
(D) Dorsal interossei
(E) Lumbricals
A

The answer is D- Dorsal interossei

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 are attached to the little finger; thus, they are injured.

39
Q
  1. A 7-year-old boy falls from a tree house and is brought to the emergency department of a local hospital. On examination, he has weak- ness in rotating his arm laterally because of an injury of a nerve. Which of the following condi- tions is most likely to cause a loss of this nerve function?
    (A) Injury to the lateral cord of the brachial plexus
    (B) Fracture of the anatomic neck of the humerus
    (C) Knife wound on the teres major muscle
    (D) Inferior dislocation of the head of the humerus
    (E) A tumor in the triangular space in the shoulder region
A
  1. The answer is D- Inferior dislocation of the head of the humerus

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 quadrangu- lar space accompanied by the posterior humeral circumflex vessels around the surgical neck of the humerus, and supplies the deltoid and teres minor, which are lateral rotators of the arm.

40
Q
  1. A 49-year-old woman is diagnosed as hav- ing a large lump in her right breast. Lymph from the cancerous breast drains primarily into which of the following nodes?
    (A) Apical nodes
    (B) Anterior (pectoral) nodes
    (C) Parasternal (internal thoracic) nodes (D) Supraclavicular nodes
    (E) Nodes of the anterior abdominal wall
A

The answer is B- Anterior (pectoral) nodes

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

41
Q 
41. A 17-year-old boy fell from his motorcycle and complains of numbness of the lateral part of the arm. Examination reveals that the axillary nerve is severed. Which of the following types of axons is most likely spared?
(A) Postganglionic sympathetic axons 
(B) Somatic afferent axons
(C) Preganglionic sympathetic axons 
(D) General somatic efferent axons 
(E) General visceral afferent axons
A

The answer is C Preganglionic sympathetic axons

The axillary nerve contains no preganglionic sympathetic general visceral efferent (GVE) fibers, but it contains postganglionic sympathetic GVE fibers. The axillary nerve also contains GSA, GSE, and general visceral afferent (GVA) fibers.

42
Q 
42. 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?
(A) Triquetral bone
(B) Trapezoid bone
(C) Extensor indicis tendon
(D) Abductor pollicis brevis tendon 
(E) Radial artery
A

The answer is E- Radial artery

The radial artery lies on the floor of the anatomic snuffbox. Other structures are not related to the snuffbox. The tendons of the extensor pollicis longus, extensor pollicis brevis, and abductor pollicis longus muscles form the boundaries of the anatomic snuffbox. The scaphoid and trapezium bones form its floor.

43
Q 
43. A rock climber falls on his shoulder, result- ing in a chipping off of the lesser tubercle of the humerus. Which of the following structures would most likely have structural and functional damage?
(A) Supraspinatus muscle 
(B) Infraspinatus muscle
(C) Subscapularis muscle 
(D) Teres minor muscle
(E) Coracohumeral ligament
A

The answer is C- Subscapularis muscle

The subscapularis muscle inserts on the lesser tubercle of the humerus. The supraspinatus, infraspinatus, and teres minor muscles insert on the greater tubercle of the humerus. The coracohumeral ligament attaches to the greater tubercle.

44
Q 
44. A 22-year-old female Macarena dancer fell from the stage and complains of elbow pain and inability to supinate her forearm. Which of the following nerves are most likely injured from this accident?
(A) Median and ulnar nerves
(B) Axillary and radial nerves
(C) Radial and musculocutaneous nerves
(D) Ulnar and axillary nerves
(E) Musculocutaneous and median nerves
A

The answer is C- Radial and musculocutaneous nerves

The supinator and biceps brachii muscles supinate the forearm. The supina- tor is innervated by the radial nerve, and the biceps brachii is innervated by the musculocuta- neous nerve.

45
Q
  1. The lateral portion of the fractured clavicle is displaced downward by which of the following?
    (A) Deltoid and trapezius muscles
    (B) Pectoralis major and deltoid muscles
    (C) Pectoralis minor muscle and gravity
    (D) Trapezius and pectoralis minor muscles
    (E) Deltoid muscle and gravity

Questions 45 to 47: A 37-year-old female patient has a fracture of the clavicle. The junction of the middle and lateral thirds of the bone exhibits overriding of the medial and lateral fragments. The arm is rotated medially, but it is not rotated laterally.

A

The answer is E-Deltoid muscle and gravity

The lateral fragment of the clavicle is displaced downward by the pull of the deltoid muscle and gravity. The medial fragment is displaced upward by the pull of the sterno- cleidomastoid muscle. None of the other muscles are involved.

46
Q 
46. Which of the following muscles causes up- ward displacement of the medial fragment?
(A) Pectoralis major
(B) Deltoid
(C) Trapezius
(D) Sternocleidomastoid
(E) Scalenus anterior

Questions 45 to 47: A 37-year-old female patient has a fracture of the clavicle. The junction of the middle and lateral thirds of the bone exhibits overriding of the medial and lateral fragments. The arm is rotated medially, but it is not rotated laterally.

A

The answer is D- Sternocleidomastoid

The sternocleidomastoid muscle is attached to the superior border of the medial third of the clavicle, and the medial fragment of a fractured clavicle is displaced upward by the pull of the muscle.

47
Q
  1. Which of the following conditions is most likely to occur secondary to the fractured clavicle?

(A) A fatal hemorrhage from the brachiocephalic vein
(B) Thrombosis of the subclavian vein, causing a pulmonary embolism
(C) Thrombosis of the subclavian artery, caus- ing an embolism in the ascending aorta
(D) Damage to the upper trunk of the brachial plexus
(E) Damage to the long thoracic nerve, caus- ing the winged scapula

Questions 45 to 47: A 37-year-old female patient has a fracture of the clavicle. The junction of the middle and lateral thirds of the bone exhibits overriding of the medial and lateral fragments. The arm is rotated medially, but it is not rotated laterally.

A

The answer is B- Thrombosis of the subclavian vein, causing a pulmonary embolism

The fractured clavicle may damage the subclavian vein, resulting in a pulmonary embolism; cause thrombosis of the subclavian artery, resulting in embolism of the brachial artery; or damage the lower trunk of the brachial plexus.

48
Q 
48. Which of the following nerves is most likely injured as a result of this accident?
(A) Axillary
(B) Musculocutaneous 
(C) Radial
(D) Median
(E) Ulnar
A

The answer is E- Ulnar

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.

49
Q 
49. Which of the following muscles is most likely paralyzed as a result of this accident?
(A) Extensor pollicis brevis 
(B) Abductor pollicis longus 
(C) Abductor pollicis brevis 
(D) Adductor pollicis
(E) Opponens pollicis
A

The answer is D- Adductor pollicis

The ulnar nerve innervates the adductor pollicis muscle. The radial nerve innervates the abductor pollicis longus and extensor pollicis brevis muscles, whereas the median nerve innervates the abductor pollicis brevis and opponens pollicis muscles.

50
Q
  1. After this injury, the patient is unable to do
    which of the following?
    (A) Flex the proximal interphalangeal joint of his ring finger
    (B) Flex the DIP joint of his index finger
    (C) Feel sensation on his middle finger
    (D) Abduct his thumb
    (E) Adduct his index finger
A

The answer is E- Adduct his index finger

The fingers are adducted 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 interphalangeal joints are flexed by the flexor digitorum superficialis, which is innervated by the median nerve. However, the DIP joints of the index and middle fingers are 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 pollicis brevis is innervated by the median nerve; the abductor pollicis longus is innervated by the radial nerve.

51
Q 
51. Which of the following nerves is most likely injured as a result of this accident?
(A) Musculocutaneous
 (B) Axillary
(C) Radial
(D) Median
(E) Ulnar

Questions 51 to 55:
A 10-year-old boy falls off his bike, has difficulty in moving his shoulder, and is brought to the emergency department. His radiograph and angiograph reveal fracture of the surgical neck of his humerus and bleed- ing from the point of the fracture.

A

The answer is B- Axillary

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 dis- location of the humerus. The other nerves listed are not in contact with the surgical neck of the humerus.

52
Q 
52. Following this accident, the damaged nerve causes difficulty in abduction, extension, and lateral rotation of his arm. Cell bodies of the injured nerve involved in movement of his arm are located in which of the following structures?
(A) Dorsal root ganglion
(B) Sympathetic chain ganglion
(C) Anterior horn of the spinal cord
(D) Lateral horn of the spinal cord
(E) Posterior horn of the spinal cord

Questions 51 to 55: A 10-year-old boy falls off his bike, has difficulty in moving his shoulder, and is brought to the emergency department. His radiograph and angiograph reveal fracture of the surgical neck of his humerus and bleed- ing from the point of the fracture.

A

The answer is C - Anterior horn of the spinal cord

The (injured) axillary nerve contains GSE fibers whose cell 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 GSA and 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 T1 and L2 contains cell bodies of sympathetic preganglionic fibers. The posterior horn of the spinal cord contains cell bodies of interneurons.

53
Q 
53. 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 structures?
(A) Anterior horn of the spinal cord
(B) Posterior horn of the spinal cord
(C) Lateral horn of the spinal cord
(D) Dorsal root ganglia
(E) Sympathetic chain ganglia

Questions 51 to 55: A 10-year-old boy falls off his bike, has difficulty in moving his shoulder, and is brought to the emergency department. His radiograph and angiograph reveal fracture of the surgical neck of his humerus and bleed- ing from the point of the fracture.

A

The answer is D- Dorsal root ganglia

Axillary nerve contains GSE, GSA, GVA, and sympathetic postganglionic GVE fibers. 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 post- ganglionic GVE fibers are located in the sympathetic chain ganglia, but cell bodies of sympa- thetic preganglionic GVE fibers lie in the lateral horn of the spinal cord.

54
Q
  1. This accident most likely leads to the
    damage of which of the following arteries?
    (A) Axillary
    (B) Deep brachial
    (C) Posterior humeral circumflex
    (D) Superior ulnar collateral
    (E) Scapular circumflex

Questions 51 to 55: A 10-year-old boy falls off his bike, has difficulty in moving his shoulder, and is brought to the emergency department. His radiograph and angiograph reveal fracture of the surgical neck of his humerus and bleed- ing from the point of the fracture.

A

The answer is C- Posterior humeral circumflex

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.

55
Q 
55. Following this accident, the boy has weak- ness in rotating his arm laterally. Which of the following muscles are paralyzed?
(A) Teres major and teres minor
(B) Teres minor and deltoid
(C) Infraspinatus and deltoid
(D) Supraspinatus and subscapularis
(E) Teres minor and infraspinatus

Questions 51 to 55: A 10-year-old boy falls off his bike, has difficulty in moving his shoulder, and is brought to the emergency department. His radiograph and angiograph reveal fracture of the surgical neck of his humerus and bleed- ing from the point of the fracture.

A

The answer is B- Teres minor and deltoid

The lateral rotators of the arm include the teres minor, deltoid, and infraspi- natus muscles, but the infraspinatus muscle is innervated by the suprascapular nerve.

56
Q 
56. The blood most likely comes from which of the following arteries?
(A) Brachial
(B) Radial
(C) Ulnar
(D) Common interosseous
(E) Superior ulnar collateral

Questions 56 to 57: A 64-year-old man with a history of liver cirrhosis has been examined
for hepatitis A, B, and C viruses. In an attempt to obtain a blood sample from the patient’s median cubital vein, a registered nurse inadvertently procures arterial blood.

A

The answer is A- Brachial

The median cubital vein lies superficial to the bicipital aponeurosis and thus separates it from the brachial artery, which can be punctured during intravenous injections and blood transfusions.

57
Q 
57. During the procedure, the needle hits a nerve medial to the artery. Which of the follow- ing nerves is most likely damaged?
(A) Radial
(B) Median
(C) Ulnar
(D) Lateral antebrachial
(E) Medial antebrachial

Questions 56 to 57: A 64-year-old man with a history of liver cirrhosis has been examined
for hepatitis A, B, and C viruses. In an attempt to obtain a blood sample from the patient’s median cubital vein, a registered nurse inadvertently procures arterial blood.

A

The answer is B- Median

The median nerve is damaged because it lies medial to the brachial artery. The bicipital aponeurosis lies on the brachial artery and the median nerve. The V-shaped cubi- tal fossa contains (from medial to lateral) the median nerve, brachial artery, biceps tendon, and radial nerve. The ulnar nerve runs behind the medial epicondyle; the lateral and medial ante- brachial cutaneous nerves are not closely related to the brachial artery.

58
Q 
58. Which of the following nerves is most likely damaged?
(A) Axillary nerve
(B) Radial nerve
(C) Musculocutaneous nerve 
(D) Median nerve
(E) Ulnar nerve

Questions 58 to 62: A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus.

A

The answer is B- Radial nerve

The radial nerve runs in the radial groove on the back of the shaft of the humerus with the profunda brachii artery. The 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.

59
Q 
59. 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?
(A) Anterior horn of the spinal cord 
(B) Posterior horn of the spinal cord 
(C) Lateral horn of the spinal cord 
(D) Sympathetic chain ganglion
(E) Dorsal root ganglion

Questions 58 to 62: A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus.

A

The answer is D- Sympathetic chain ganglion

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 (arrector pili muscles). The radial nerve also contains GSE fibers whose cell bodies are located in the anterior horn of the spinal cord, and GSA and GVA fibers whose cell bodies are located in the dorsal root ganglion. The lateral horn of the spinal cord between T1 and L2 contains cell bodies of sympathetic pregangli- onic nerve fibers.

60
Q
  1. Following this accident, the patient has no cutaneous sensation in which of the following areas?
    (A) Medial aspect of the arm
    (B) Lateral aspect of the forearm
    (C) Palmar aspect of the second and third
    digits
    (D) Area of the anatomic snuffbox
    (E) Medial one and one-half fingers

Questions 58 to 62: A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus.

A

The answer is D- Area of the anatomic snuffbox

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 is inner- vated by the lateral antebrachial cutaneous nerve of the musculocutaneous nerve; the palmar aspect of the second and third digits is innervated by the median nerve; and the medial one and one-half fingers are innervated by the ulnar nerve.

61
Q 
61. Which of the following arteries may be damaged?
(A) Brachial artery
(B) Posterior humeral circumflex artery 
(C) Profunda brachii artery
(D) Radial artery
(E) Radial recurrent artery

Questions 58 to 62: A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus.

A

The answer is C- Profunda brachii artery

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.

62
Q
  1. After this accident, supination is still possible through contraction of which of the following muscles?
(A) Supinator
(B) Pronator teres 
(C) Brachioradialis 
(D) Biceps brachii
(E) Supraspinatus

Questions 58 to 62: A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus.

A

The answer is D- Biceps brachii
A lesion of the radial nerve causes paralysis of the supinator and brachioradi- alis. The biceps brachii muscle is a flexor of the elbow and also a strong supinator; thus, supina- tion is still possible through action of the biceps brachii muscle. Other muscles cannot supinate the forearm.

63
Q
  1. A cyclist is thrown over his handle bars and breaks his clavicle as he hits the ground on his shoulder. Which of the following is correct regarding the development of the clavicle?
    (A) It develops through intramembranous ossification
    (B) It is the last upper limb bone to begin ossification
    (C) The clavicle forms from somitic mesoderm
    (D) It is the first limb bone to complete
    ossification
    (E) Associated muscles form from somatic lateral plate mesoderm
A

The answer is A- It develops through intramembranous ossification

The clavicle is the only upper limb bone to develop through intramembra- nous ossification. It is the first upper limb bone to begin ossification and is the last bone to com- plete ossification. The clavicle forms from somatic lateral plate mesoderm and the associated muscles develop from somitic mesoderm (from somites).

64
Q 
64. A patient presents with pain in the neck, numbness and tingling in the fingers, and a week grip. This presentation suggests thoracic outlet syndrome. Which of the following causes has an embryological etiology?
(A) Traumatic injury
(B) Cardiovascular disease
(C) Cervical rib
(D) Pancoast tumor
(E) Scalene muscle inflammation
A

The answer is C- Cervical rib

A cervical rib is a congenital abnormality that can cause thoracic outlet syn- drome because the space that transmits the neurovasculature to the arm is reduced. Other causes listed are not a result of embryological development.

65
Q 
65. If the structure indicated by the letter A is calcified, which of the following muscles is most likely paralyzed?
(A) Deltoid
(B) Teres major
(C) Teres minor
(D) Infraspinatus
(E) Subscapularis
A

The answer is (D) Infraspinatus

The scapular notch transmits the suprascapular nerve below the superior transverse ligament, whereas the suprascapular artery and vein run over the ligament. The suprascapular nerve supplies the supraspinatus and infraspinatus muscles. The axillary nerve innervates the deltoid and teres minor muscles. The subscapular nerves innervate the teres major and subscapularis muscles.

66
Q 
66. If the structure indicated by the letter B is fractured, which of the following structures is most likely injured?
(A) Musculocutaneous nerve
(B) Radial nerve
(C) Deep brachial artery
(D) Posterior humeral circumflex artery 
(E) Scapular circumflex artery
A

The answer is D. Fracture of the surgical neck of the humerus occurs commonly and damages the axillary nerve and the posterior humeral circumflex artery.

67
Q
  1. Destruction of this area would most likely cause weakness of supination and flexion of the forearm.
A

The answer is B. The radial tuberosity is the site for tendinous attachment of the biceps brachii muscle, which supinates and flexes the forearm. When the tuberosity is destroyed, the biceps brachii is paralyzed.

68
Q
  1. Destruction of this area would most likely cause weakness of pronation of the forearm and flexion of the wrist joints.
A

The answer is E. The medial epicondyle is the site of origin for the common flexor tendon and pronator teres. The common flexors include the flexor carpi radialis and ulnaris and palmaris longus muscles, which can flex the elbow and wrist joints. Thus, destruction of this area causes weakness of pronation because the pronator teres is paralyzed but the pronator quadratus is normal. Similarly, destruction of this area causes paralysis of the flexors of the wrist. However, it can be weakly flexed by the flexor pollicis longus, flexor digitorum superficialis, and profundus muscles.

69
Q
  1. A lesion of the radial nerve would most likely cause paralysis of muscles that are attached to this area.
A

The answer is D. The olecranon is the site for insertion of the triceps brachii, which is inner- vated by the radial nerve. When the olecranon is destroyed, the triceps brachii is paralyzed

70
Q 
70. Destruction of the structure indicated by the letter E most likely causes weakness of which of the following muscles?
(A) Flexor carpi radialis
(B) Palmaris longus
(C) Flexor carpi ulnaris
(D) Brachioradialis
(E) Flexor digitorum superficialis
A

The answer is C. The hook of hamate and the pisiform provide insertion for the flexor carpi
ulnaris.

71
Q
  1. If the floor of the anatomic snuffbox and origin of the abductor pollicis brevis are dam- aged, which of the following bones is most likely to be involved?
    (A) A (B) B (C) C (D) D (E) E
A

The answer is B. The scaphoid forms the floor of the anatomic snuffbox and provides a site for origin of the abductor pollicis brevis.

72
Q
  1. The patient is unable to abduct her middle finger because of paralysis of this structure.
A

The answer is D. This is the second dorsal interosseous muscle, which abducts the middle finger.

73
Q
  1. A lesion of the median nerve causes paraly- sis of this structure.
A

The answer is A. This is the flexor pollicis longus, which is innervated by the median nerve.

74
Q
  1. The patient is unable to adduct her little fin- ger because of paralysis of this structure.
A

The answer is G. This is the third palmar interosseous muscle, which adducts the little finger.

75
Q
  1. Atrophy of this structure impairs extension of both the metacarpophalangeal and interpha- langeal joints.
A

The answer is E. The extensor digitorum extends both the metacarpophalangeal and interpha- langeal joints.

Anatomy (9 decks)

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