Upper limb nerve lesions

Question 1

numbness over lateral forearm, elbow help in extension with forearm pronated
(weak elbow flexion and forearm supination)
no biceps reflex
wasting of anterior compartment of arm

Answer 1

musculocutaneous nerve palsy

Question 2

What might cause a radial nerve palsy?

Answer 2

fractures - humerus or radius
stab wounds to antecubital fossa, forearm, wrist
crutch palsy
saturday night palsy (=pt falls asleep w arm hanging over back of chair)
honeymoon palsy (=some falls asleep w head on pt’s arm)
very tight plaster casts, wristbands, handcuffs
prolonged tourniquet use

Question 3

What might cause a musculocutaneous nerve palsy?

Answer 3

stab wound to the upper arm

N.B. this nerve injury is very rare, as the nerve is protected by the overlaying biceps muscle

Question 4

numbness over upper outer arm
shoulder adducted and internally rotated
(very weak shoulder abduction, flexion, extension and external rotation)
shoulder bones very prominent (deltoid wasting)

Answer 4

axillary nerve palsy

Question 5

What might cause an axillary nerve palsy?

Answer 5

fracture of surgical neck of humerus
stab wound to posterior shoulder
anterior shoulder dislocation
crutch palsy (pressure of crutches on armpits)

Question 6

numbness over thenar eminence and lateral aspect of hand
weak forearm pronation, wrist flexion and abduction and weak finger flexion (of first 3 fingers), weak pincer grip
can’t make a fist - hand of benediction deformity
wasting of anterior forearm and thenar eminence

Answer 6

median nerve palsy

Question 7

What might cause an ulnar nerve palsy?

Answer 7

humerus fracture
stab wounds to antecubital fossa, forearm, wrist –> including venepuncture and cannulas!
compression of cubital tunnel in elbow
compression of Guyon’s canal in wrist

Question 8

numbness of skin on posterior arm and forearm and back of hand
arm and wrist flexed
(weak elbow, wrist, thumb, MCPJ extension)
no triceps + supinator reflexes
wasted triceps and posterior forearm
WRIST drop

Answer 8

radial nerve palsy

Question 9

What might cause a median nerve palsy?

Answer 9

humerus fracture
stab wounds to antecubital fossa, forearm, wrist –> including venepuncture and cannulas!
self harm wrist lacerations
carpal tunnel syndrome

Question 10

numbness over hypothenar eminence and two medial fingers
weak wrist flexion and adduction
weak flexion of ring and little fingers
claw hand

Answer 10

ulnar nerve palsy

Question 11

atrophy of supraspinatus and infraspinatus muscles

Answer 11

suprascapular nerve palsy

Question 12

winging of scapula on arm abduction

Answer 12

long thoracic nerve palsy

Question 13

claw hand in all digits atrophy of intrinsic hand muscles

sensory loss along ulnar border of hand and forearm

Answer 13

lower trunk of brachial plexus (C8/T1) = Klumpske’s palsy

Question 14

limp arm, medially rotated, extended at elbow and pronated with hand pointing backwards (Waiter’s tip)
loss of sensation over lateral arm and forearm

Answer 14

upper brachial plexus (C5/C6) = Erb’s palsy

Question 15

What might cause an upper brachial plexus injury?

Answer 15

motorcycle accidents

doctor pulling on baby’s arm during birth

Question 16

What might cause a lower brachial plexus injury?

Answer 16

motorcycle accidents
breech birth (baby's arm above head)