The superficial branch of the radial nerve: an anatomic study with surgical implications.

Twenty fresh cadaver extremities were dissected to delineate and quantify the course of the superficial branch of the radial nerve. This branch bifurcated from the radial nerve at the level of the lateral humeral epicondyle in eight specimens, and in all specimens the bifurcation was no more than 2.1 cm from the lateral epicondyle. It continued distally, deep to the brachioradialis and became subcutaneous a mean of 9.0 cm proximal to the radial styloid, traversing between the tendons of the brachioradialis and extensor carpi radialis longus. The superficial branch of the radial nerve branched a mean of 5.1 cm proximal to the radial styloid. Distally, at the level of the extensor retinaculum, the closest branches to the center of the first dorsal compartment and to Lister's tubercle were mean distances of 0.4 and 1.6 cm, respectively. In the hand, the superficial branch of the radial nerve most commonly supplied branches to the thumb, the index finger, and the dorsoradial aspect of the long finger. Knowledge of the course of the superficial branch of the radial nerve will help prevent injury during operative procedures on the radial side of the hand, wrist, and forearm and will aid in its localization in treatment of traumatic injuries or performance of nerve blocks in its distribution.