Brachial plexus/upper extremity nerve lesions

Question 1

what is the presentation of an axillary nerve lesion?

Answer 1

flattened deltoid
loss of arm abduction at shoulder (>15 deg)
loss of sensation over deltoid and lateral arm

Question 2

what is the presentation of a musculocutaneous nerve lesion?

Answer 2

decreased biceps reflex
weakness of forearm flexion and supination
loss of sensation over lateral forearm

Question 3

what is the presentation of a radial nerve lesion?

Answer 3

wrist drop (loss of elbow, wrist, and finger extension)
decreased grip strength (wrist extension necessary for max action of flexors)
loss of sensation over posterior arm/forearm and dorsal hand

Question 4

what is presentation of a proximal median nerve lesion?

Answer 4

Pope’s blessing (when asked to make a fist)
ape hand with atrophy of thenar eminence
loss of wrist flexion, flexion of lateral fingers, thumb opposition, lumbricals of index and middle fingers
loss of sensation over thenar eminence and dorsal and palmar aspects of lateral 3 1/2 fingers

Question 5

what is presentation of a distal median nerve lesion?

Answer 5

median claw (when asked to extend fingers or at rest)
ape hand with atrophy of thenar eminence
loss of wrist flexion, flexion of lateral fingers, thumb opposition, lumbricals of index and middle fingers

Question 6

what is presentation of a distal ulnar nerve lesion?

Answer 6

ulnar claw when asked to extend fingers
loss of wrist flexion, flexion of medial fingers, abduction and adduction of fingers (interossei), actions of medial 2 lumbrical muscles
loss of sensation over medial 1 1/2 fingers including hypothenar eminence

Question 7

what is presentation of a proximal ulnar nerve lesion?

Answer 7

OK gesture when asked to make a fist
radial deviation of wrist upon flexion
loss of wrist flexion, flexion of medial fingers, abduction and adduction of fingers (interossei), actions of medial 2 lumbrical muscles
loss of sensation over medial 1 1/2 fingers including hypothenar eminence

Question 8

what is presentation of an upper brachial plexus lesion?

Answer 8

Erb palsy/waiter/s tip
lesion affects axillary, musculocutaneous, and suprascapular nerves
deficit in: Deltoid, supraspinatous, Infraspinatous, Biceps (remember hERB gets DIBs on tips)
functional deficit in: abduction, lateral rotation, flexion, supination

Question 9

what is presentation of a lower brachial plexus lesion?

Answer 9

Klumpke palsy
lesion affects median and ulnar nerves
deficit in: intrinsic hand muscles
functional deficit: total claw hand

Question 10

what is presentation of compression of lower brachial plexus and subclavian vessels?

Answer 10

thoracic outlet syndrome
same as Klumpke’s palsy (intrinsic hand muscles–> total claw hand) with atrophy of intrinsic hand muscles, ischemia, pain, and edema due to vascular compression

Question 11

what is presentation of a lesion of the long thoracic nerve?

Answer 11

winged scapula
deficit in serratus anterior –> inability to anchor scapula to thoracic cage so can’t abduct arm above horizontal position