The ulnar nerve supplies all the small muscles of the hand except for the lateral two lumbricals, opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis.
- inspection for claw hand and wasting of the small muscles - clawing is of the ring and little fingers due to hyperextension at the metacarpophalangeal joints and flexion of the interphalangeal joints. Clawing of the hand is greater with an ulnar nerve lesion at the wrist. If a lesion of the ulnar nerve occurs at or above the elbow then the loss of flexor digitorum profundus means that there is less of flexion of the interphalangeal joints.
- motor function: test for Froment's sign
- sensation: test for pin prick sensation over the palmar aspect of the ring finger - the ulnar nerve supplies the sensation over the palmar and dorsal aspect of the little finger and the medial half of the ring finger.