Localizing the Course of the Radial Nerve Based on Anatomical Landmarks: A Cadaveric Study

Purpose: Iatrogenic radial nerve injury during the posterior approach to the humerus is a well-documented complication. The aim of this study is to define the course and variability of the radial nerve along the posterior humerus in relationship to the medial and lateral epicondyles. Methods: With the cadaver in a lateral position, the shoulder and elbow were flexed to 90 degrees and supported as done intraoperatively. The epicondyles of the humerus were aligned and tensioned to be held parallel to the operating table. The forearm was clamped in neutral to the supporting pipe. A posterior incision was made over the humerus to expose the triceps muscle. Dissection was continued to the bone and exposure of the radial nerve was completed with care. The location where the radial nerve intersected the medial and lateral edges of the humerus was marked. Images, with a ruler placed on the humerus, were taken of the posterior arm from a standard camera setup. ImageJ was utilized to measure the distance from the epicondyles to where the radial nerve crossed the humerus. Results: Measurements are currently being performed and analyzed in arms of 25 cadavers. Conclusion: Identification of the radial nerve allows for protection of the nerve during a posterior surgical approach to the humerus. This study allows for simple guidelines for orthopedic surgeons to identify the radial nerve and limit iatrogenic injury.