Ulnar-median and median-ulnar anastomoses in the forearm: a patient report.

Reports of an ulnar-median anastomosis in the forearm (UMAF) are rare and its existence has been questioned. A patient with clinical and electrophysiologic evidence of ulnar neuropathy at the elbow (UNE) had unexpected fibrillations in the abductor pollicis brevis muscle (APB). Additional nerve conduction studies suggested both ulnar-median and median-ulnar anastomoses in the forearm. The unexpected finding of APB fibrillations in a patient with UNE should raise the possibility of the rare UMAF.