Ulnar nerve

Overview

• arises from medial cord of brachial plexus (C8, T1)

Motor to

• medial two lumbricals
• aDductor pollicis
• interossei
• hypothenar muscles: abductor digiti minimi, flexor digiti minimi
• flexor carpi ulnaris

Sensory to

• medial 1 1/2 fingers (palmar and dorsal aspects)

Patterns of damage

Damage at wrist

• 'claw hand' - hyperextension of the metacarpophalangeal joints and flexion at the distal and proximal interphalangeal joints of the 4th and 5th digits
• wasting and paralysis of intrinsic hand muscles (except lateral two lumbricals)
• wasting and paralysis of hypothenar muscles
• sensory loss to the medial 1 1/2 fingers (palmar and dorsal aspects)

Damage at elbow

• as above (however, ulnar paradox - clawing is more severe in distal lesions)
• radial deviation of wrist