AAEE case report #18: Ulnar neuropathy in the distal forearm.

A 66-year-old professional golf instructor developed pain, numbness, and weakness in an ulnar distribution, but the lesion could not be localized to either elbow or wrist by routine nerve conduction techniques. Stimulation along serial 1-cm increments in the distal forearm disclosed a point of focal conduction block approximately 7 cm proximal to the ulnar styloid. At surgery, the flexor carpi ulnaris was enlarged, with muscle fibers extending all along the normally tendinous distal portion. A dense fibrovascular band coursed from the ulnar artery to the abnormal muscle, compressing the adjacent ulnar nerve. Intraoperative electroneurography precisely localized the area of conduction abnormality and helped identify the band as the compressing structure. Within 2 months following surgical decompression there was complete resolution of conduction block with excellent clinical recovery.