Exposure of posterior interosseous branch of the radial nerve for repair or decompression in radial tunnel syndrome. A, Line of incision, forearm prone, elbow flexed. B, Nerve exposed. C, Diagram of course of nerve with arm in position A. D, Line of incision, elbow extended. ECU, extensor carpi ulnaris; ECRB, extensor carpi radialis brevis; ECRL, extensor carpi radialis longus; EDC, extensor digitorum communis.