Palmaris brevis sign in ulnar neuropathy

A case of ulnar neuropathy, selectively affecting the deep branch and showing positive palmaris brevis sign, is reported. The palmaris brevis muscle was not only intact, but also showed excessive cocontraction with abductor digiti minimi. Palmaris brevis sign, when present, is useful in clinically localizing the site of the ulnar nerve lesion. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21:675–677, 1998.