Aberrant positioning of the ulnar nerve found during carpal tunnel release: A case report

Aberrant positioning of the ulnar nerve volar to the carpal tunnel is a rare anatomic variation. We present the case of a 55-yearold female with unique ulnar nerve anatomy that was discovered intraoperatively during carpal tunnel release. The ulnar nerve was running directly adjacent to the median nerve in the distal forearm and as the median nerve traversed dorsal to the transverse carpal ligament (flexor retinaculum) to enter the carpal tunnel the ulnar nerve continued directly volar to this structure before angling towards Guyon’s Canal. The unique ulnar nerve anatomy was successfully identified, carefully dissected and managed with a successful patient outcome. Variations of the anatomy at the level of the carpal tunnel are rare but do exist. Awareness of these anatomic variations and adequate visualization of the ulnar nerve along with the surrounding structures is crucial to avoid iatrogenic injuries during carpal tunnel release.