Anatomical Study of the Motor Branches of the Radial Nerve in the Forearm.

To analyze the anatomical variations of the motor branches of the radial nerve in the elbow region. The origin, course, length, branches, motor points and relationships with neighboring structures were evaluated.  Thirty limbs from15 adult cadavers were dissected and prepared by intra-arterial injection of a 10% glycerin and formaldehyde solution.  The first branch of the radial nerve in the forearm went to the brachioradialis muscle (BR), originating proximally to the division of the radial nerve into superficial branch of the radial nerve (SBRN) and posterior interosseous nerve (PIN) in all limbs. The branches to the extensor carpi radialis longus muscle (ECRL) detached from the proximal radial nerve to its division into 26 limbs, in 2, at the dividing points, in other 2, from the PIN. In six limbs, the branches to the BR and ECRL muscles originated from a common trunk. We identified the origin of the branch to the extensor carpi radialis brevis muscle (ECRB) in the PIN in 14 limbs, in the SBRN in 12, and in the radial nerve in only 4. The branch to the supinator muscle originated from the PIN in all limbs.  Knowledge of the anatomy of the motor branches of the radial nerve is important when performing surgical procedures in the region (such as the approach of the proximal third and the head of the radius, release of compressive syndromes of the posterior interosseous nerve and radial tunnel, and distal nerve transfers) in order to understand the order of recovery of muscle function after a nerve injury.