Palmar cutaneous branch of the ulnar nerve.

With recent attention being placed on the median palmar cutaneous nerve, a surgical approach, ulnar to the axis of the ring finger ray, has been advocated for median nerve decompression at the wrist. Painful hypothenar neuromas have developed in two patients with this type of incision. After dissecting 21 cadaver forearms and hands, three classic and two variants of the ulnar palmar cutaneous nerve were identified and found to emerge in the subcutaneous tissue ulnar to the ring finger ray. The terminal branches supplied the hypothenar skin and extended radially to the ring finger ray axis. Because of these anatomic findings, we recommend an incision in line with the ring finger ray axis in an attempt to avoid injury to both ulnar and median palmar cutaneous nerves.