Upper limb anatomy

Question 1

Musculocutaneous nerve (C5-C7)

Answer 1

Elbow flexion (supplies biceps brachii) and supination

Lateral part of the forearm

Isolated injury rare - usually injured as part of brachial plexus injury

Question 2

Axillary nerve (C5,C6)

Answer 2

Shoulder abduction (deltoid muscle)
Inferior region of the deltoid muscle

Humeral neck fracture/dislocation

Results in flattened deltoid

Question 3

Radial nerve (C5-C8)

Answer 3

Extension (forearm, wrist, fingers, thumb)
Small area between the dorsal aspect of the 1st and 2nd metacarpals

Humeral midshaft fracture

Palsy results in wrist drop

Question 4

Median nerve (C6, C8, T1)

Answer 4

LOAF* muscles

Features depend on the site of the lesion:
wrist: paralysis of thenar muscles, opponens pollicis
elbow: loss of pronation of forearm and weak wrist flexion

Palmar aspect of lateral 3½ fingers

Wrist lesion → carpal tunnel syndrome

Question 5

Ulnar nerve (C8, T1)

Answer 5

Intrinsic hand muscles except LOAF*

Wrist flexion

Medial 1½ fingers

Medial epicondyle fracture

Damage may result in a ‘claw hand’

Question 6

Long thoracic nerve (C5-C7)

Answer 6

Serratus anterior

Often during sport e.g. following a blow to the ribs. Also possible complication of mastectomy

Damage results in a winged scapula