This can result from a compression of the nerve on a hard surface (like a chair arm, desk, operating table, etc).

Numbness and tingling wherever the ulnar nerve is distributed in the hand.

Interosseous muscle wasting between the thumb and index finger is seen.

Abduction and adduction by interosseous muscles is diminished, and then lost.

Patient experiences numbness and tingling in the little finger, and the medial half of the ring finger.

In ulnar palsy, the opposite of the optimal position of the hand for the ring finger and the pinky will happen. The ring finger and pinky will have extension of the metacarpophalangeal joints and flexion of the proximal interphalangeal joint and distal interphalangeal joint.

Patient will have what is known as “ulnar claw”

Interosseous muscles affected, and you cannot cup your hand.