Anatomy of the Posterior Antebrachial Cutaneous Nerve, Revisited

To describe the branching pattern of the posterior antebrachial cutaneous nerve (PABCN) and to corroborate measurements and observations reported by previous authors.

Using 28 fresh-frozen cadaver specimens, we dissected the PABCN from its origin from the radial nerve to its terminal arborization in the distal forearm. Measurements relative to the lateral humeral epicondyle were recorded. The course of the nerve over the muscles of the mobile wad and its branching pattern in the proximal forearm were noted.

The PABCN originated from the radial nerve at a mean of 14.2 cm proximal to the lateral epicondyle. The fascial hiatus through which the PABCN emerged to become superficial was a mean of 8.2 cm proximal to the lateral epicondyle. All specimens had at least 1 longitudinal branch that passed a mean of 2.8 cm anterior to the lateral epicondyle. Thirty-two percent of specimens had a lesser proximal branch in the distal third of the lateral arm; 86% had an epicondylar branch to the lateral epicondyle; and 21% had a second longitudinal branch. Ninety-three percent had a longitudinal branch coursing over the interval between the brachioradialis and the extensor carpi radialis longus in the proximal forearm.

After becoming superficial in the distal brachium, the PABCN typically gives off a discrete epicondylar branch and then continues distally in the forearm as 1 or 2 longitudinal branches. In addition, in the proximal third of the forearm, a consistent longitudinal branch of the PABCN courses over the interval between the brachioradialis and the extensor carpi radialis longus. This review confirms previous observations of the PABCN.

Knowledge of the course of the PABCN will assist surgeons in identifying and avoiding injury in clinical situations such as plating the proximal radius or releasing the radial tunnel.