A surgical approach to the motor branch of the ulnar nerve

Isolated injury to the motor branch of the ulnar nerve is a relatively rare injury, often initially misdiagnosed. If repair is attempted through the original laceration without complete motor branch exposure, results can be less than satisfactory. A recent case illustrates this injury and provides us with an opportunity to review the surgical anatomy of the motor branch of the ulnar nerve. The surgical approach to the motor branch has been detailed and specifically emphasizes complete motor branch exposure from the main ulnar nerve trunk to the most distal motor branch entry into the adductor pollicis muscle. This approach permits definition of the exact level of the nerve injury, preservation of any intact proximal fine motor branches, and facilitates the mechanics of nerve repair.