features of an ulnar nerve lesion at the elbow

Last reviewed 01/2018

The clinical features of an ulnar nerve lesion at the elbow include:

• wasting of the flexor carpi ulnaris and the ulnar half of the flexor digitorum:
• is apparent on the inner aspect of the flexor surface of the forearm
• weakness of flexor carpi ulnaris causes the hand to deviate to the radial side as the wrist is flexed

• wasting of the small muscles of the hand except the thenar eminence and the first two lumbricals

• clawing of the ring and little fingers (main en griffe):
• loss of the 3rd and 4th lumbricals and all the interossei results in:
• hyperextension of the metacarpophalangeal joints
• flexion of the interphalangeal joints

• paralysis of the hypothenar muscles:
• abolishes abduction of the little finger

• paralysis of the interossei:
• abolishes abduction and adduction of the fingers

• paralysis of the adductor pollicis:
• weakens adduction of the thumb which is most evident when a piece of paper is grasped in a pincer grip between thumb and index finger (Froment's sign)

• numbness and tingling:
• over the two ulnar fingers and the ulnar border of the palm