Upper extremity nerves

Question 1

Axillary nerve ( C5-C6)

Answer 1

Cause of injury: fractured surgical neck if humerus; anterior dislocation of humerus

Presentation: Flattened deltoid. Loss of arm abduction at shoulder and loss of sensation over deltoid muscle and lateral arm.

Question 2

Musculocutaneous (C5-C7)

Answer 2

Cause of injury: Upper trunk compression

Presentation: Loss of forearm flexion and supination and loss of sensation over lateral forearm.

Question 3

Radial (C5-T1)

Answer 3

Cause of injury: Midshaft fracture of humerus; compression of axilla due to crutches or saturday night palsy.

Presentation: Wrist drop: loss of elbow, wrist, and finger extension, decreased grip strength and loss of sensation over posterior arm/forearm and dorsal hand.

Question 4

Median (C5-T1)

Answer 4

Cause of injury: Supracondylar fracture of humerus (proximal lesion); carpal tunnel syndrome and wrist laceration (distal lesion)

Presentation: “ape hand” and “pope’s blessing”. Loss of wrist flexion, flexion of lateral fingers, thumb opposition, lumbricals of 2nd and 3rd digits. Loss of sensation over thenar eminence and dorsal aspects of lateral 3 1/2 fingers with proximal lesion. Tinel sign.

Question 5

Ulnar (C8-T1)

Answer 5

Cause of injury: Fracture of medial epicondyle of humerus “funny bone”; fractured hook of hamate

Presentation: “Ulnar claw” on digit extension. Radial deviation of wrist upon flexion. Loss of wrist flexion, flexion of medial fingers, abduction and adduction of fingers, actions of medial two lumbricals. Loss of sensation over medial 1 1/2 fingers including hypothenar eminence.

Question 6

Recurrent branch of median nerve ( C5-T1)

Answer 6

Cause of injury: Superficial laceration on palm

Presentation: “Ape hand”, loss of thenar muscle group: opposition, abduction, and flexion of thumb. No loss of sensation.