The dorsal cutaneous branch of the ulnar nerve: an anatomical study.

There are significant variations in the anatomy of the dorsal cutaneous branch of the ulnar nerve. The dorsal cutaneous branch is at a risk of injury during a therapy for the ulnar side of the wrist. The purpose of this study is to measure the variations of the dorsal cutaneous branch. We studied 30 embalmed cadaver specimens. In its course, two division patterns of the dorsal cutaneous branch were identified, namely proximal and distal types. The proximal type went around the ulna proximal to the ulnar styloid process, and directed toward the ulnodorsal aspect. The distal type went around to the ulnodorsal aspect, distal to the styloid process. The proximal type was found in 21 of 30 cadavers, and the distal type was found in nine of 30 cadavers.