Upper Limb Nerve Lesions

Question 1

upper trunk compression (Erb-Duchenne syndrome) and herniation of disk between C4 and C5 can cause C5 root lesion. what is the location of the dermatome affected? what muscles are affected?

Answer 1

posterior shoulder, upper lateral arm

deltoid, rotator cuff, biceps, brachioradialis

Question 2

upper trunk compression (Erb-Duchenne syndrome) and herniation of disk between C5 and C6 can cause C6 root lesion. what is the location of the dermatome affected? what muscles are affected?

Answer 2

lateral forearm, thenar eminence, dorsal and palmar sides of the thumb and index finger

biceps, brachiradialis, brachialis, supinator

Question 3

what reflex is suppressed with a lesion to root C5 or C6?

Answer 3

biceps tendon

Question 4

cervical spondylosis or herniation of disk between C6 and C7 can cause lesion of root C7. what is the location of the dermatome affected? what muscles are affected?

Answer 4

midpalm, dorsal and palmar sides of middle finger

latissimus dorsi, pectoralis major, triceps, wrist extensors

Question 5

what reflex is suppressed with lesion to root C7?

Answer 5

triceps tendon

Question 6

a lower trunk compression by cervical rib or pancoast tumor (Klumpke’s paralysis) can cause lesion to root C8. what is the location of the dermatome affected? what muscles are affected?

Answer 6

hypothenar eminence, dorsal and palmar sides of ring and little finger

finger flexors, wrist flexors, intrinsic hand muscles

Question 7

a lower trunk compression by cervical rib or pancoast tumor (Klumpke’s paralysis) can cause lesion to root T1. what is the location of the dermatome affected? what muscles are affected?

Answer 7

medial arm and medial forearm to wrist

intrinsic hand muscles

Question 8

what can cause a lesion to the axillary nerve (C5, C6)?

Answer 8

fracture of surgical neck of humerus, dislocated humeral head

Question 9

a lesion to axillary nerve causes altered cutaneous sensation where? and weakness of what muscle actions?

Answer 9

over deltoid insertion

abduction at shoulder

Question 10

what can cause a lesion to the radial nerve (C5-C8)?

Answer 10

fracture midshaft of humerus, subluxation of radial head, dislocated humeral head, dislocated humeral head, compression in axilla

Question 11

a lesion to radial nerve causes altered cutaneous sensation where? and weakness of what muscle actions?

Answer 11

over first dorsal interosseous, anatomic snuffbox

extension at wrist, extension of all fingers at MP joint, supination, thumb extension and abduction

Question 12

wrist drop is a common sign of lesion to what nerve?

Answer 12

radial nerve

Question 13

ape hand is a common sign of a lesion to what nerve?

Answer 13

distal lesion to median nerve

Question 14

what are common causes of distal lesions to the median nerve (C6-T1)?

Answer 14

carpal tunnel syndrome, dislocated lunate

Question 15

a distal lesion to the median nerve causes altered cutaneous sensation where? and weakness of what muscle actions?

Answer 15

lateral 3 1/2 digits

opposition of thumb

Question 16

ulnar deviation of wrist and hand of benediction are common sign of lesions to what nerve?

Answer 16

proximal lesion to median nerve

Question 17

what are common causes of proximal lesions to the median nerve?

Answer 17

fracture of supracondylar humerus, compression between heads of pronator teres

Question 18

a proximal lesion to the median nerve causes altered cutaneous sensations where? and weakness of what muscle actions?

Answer 18

lateral 3 1/2 digits, thenar eminence

distal muscles and flexion at wrist, flexion of lateral fingers, flexion of thumb, pronation

Question 19

claw hand is a common sign of lesion to what nerve?

Answer 19

distal lesion to ulnar nerve, and proximal lesion to ulnar nerve

Question 20

what is a common cause of a distal lesion to the ulnar nerve (C8, T1)?

Answer 20

fracture of hook of hamate

Question 21

a distal lesion to the ulnar nerve causes altered cutaneous sensation where? and weakness of what muscle actions?

Answer 21

medial 1 1/2 digits, hypothenar eminence

abduction and adduction of fingers, adduction of thumb (ex. holding paper between fingers), extension of fingers

Question 22

radial deviation of wrist is a common sign of lesion to what nerve?

Answer 22

proximal lesion to ulnar nerve

Question 23

what are common causes of proximal lesions to the ulnar nerve?

Answer 23

fracture of or trauma at medial epicondyle of humerus, fracture of clavicle

Question 24

a proximal lesion to the ulnar nerve can cause altered cutaneous sensation where? and weakness of what muscle actions?

Answer 24

medial 1 1/2 digits, hypothenar eminence

distal muscles and flexion of medial fingers, flexion at wrist

Question 25

trauma and upper trunk compression can cause lesion to musculocutaneous nerve (C5-C7). where are sites of altered cutaneous sensation? what muscle actions are weakened?

Answer 25

lateral forearm

flexion at elbow, supination