Short-segment incremental studies to localize ulnar nerve entrapment at the wrist.

Precise electrophysiologic localization of ulnar neuropathy at the wrist (UNW) is often problematic. In the last year, we evaluated only two patients who presented clinically with UNW. Routine electrophysiologic techniques were nondiagnostic for UNW. In contrast, short-segment incremental studies (SSIS) across the wrist demonstrated conduction block and segmental slowing of nerve conduction across the wrist in both patients. We conclude that SSIS is a valuable tool for diagnosis, precise localization, and prognosis of UNW.