Upper Extremity Nerves

Question 1

Axillary (C5, C6)

Answer 1

Typical injury: Fractured surgical neck of humerus, dislocation of humeral head

Motor deficit: Deltoid - arm abduction at shoulder

Sensory deficit: Over deltoid muscle

Sign: Atrophied deltoid

Question 2

Radial (C5-T1)

Answer 2

Typical injury: Fracture at midshaft of humerus; “Saturday night palsy” (extended compression of axilla by back of chair or crutches)

Motor deficit: “BEST extensors”-
Brachioradialis, Extensors of wrist and fingers,
Supinator, Triceps

Sensory deficit: Posterior arm and dorsal hand and thumb

Sign: Wrist drop

Question 3

Median (C5-C8, T1)

Answer 3

Typical injury: Fracture of supracondylar humerus (proximal lesion)

Motor deficit: Opposition of thumb
Lateral finger flexion
Wrist flexion

Sensory deficit: Dorsal and palmar aspects of lateral 31/2 fingers, thenar eminence

Sign: “Ape hand”; “Pope’s blessing” (hand)

Question 4

Ulnar (C8, T1)

Answer 4

Typical injury: Fracture of medial epicondyle of humerus, “funny bone” (proximal lesion)

Motor deficit: Medial finger flexion
Wrist flexion

Sensory deficit: Medial 11/2 fingers, hypothenar eminence

Sign: Radial deviation of wrist upon wrist flexion

Question 5

Musculocutaneous

Answer 5

Typical injury: Upper trunk compression

Motor deficit: Biceps, brachialis, coracobrachialis
Flexion of arm at elbow

Sensory deficit: Lateral forearm

Sign: