Trifurcated radial nerve in the spiral groove of the humerus.

A 62-year-old man presented with a nonunion of the humerus shaft. Using a standard triceps splitting approach, a longitudinal incision along the posterior aspect of the arm was created. Three independent radial nerves coursed posteriorly and inferolaterally around the humerus were identified in spiral groove. Three nerves resembled in the size, color, and course in the operative field. Although the prevalence of the anomaly is probably quite low, the possibility of identification of this anomalous condition of radial nerve should be kept in mind when performing posterior approach on the humerus.