[Functional neuroanatomy of the radial nerve in the region of the long wrist and finger joint extensors and the supinator groove].

Basing on electrophysiological data measured by us we studied the course of the radial nerve or its motoric branches with regard to anatomically conditioned bony contractions and their possible significance for pain experienced at the radial epicondyle of humerus, the pain being known under several synonymous designations. To differentiate between the various pathomechanisms discussed in the literature, we performed longitudinal and transversal dissections on a total of 40 cadaveric arms. We found as constant variations to the topographic anatomy published in the standard literature a regularly extended and (in relation to the other muscles we examined) exposed course of the nerve branch proceeding towards the m. extensor carpi radialis brevis. As the only long wrist extensor muscle this is innervated in most cases from the superficial end branch of the radial nerve. The origin of the muscle projected regularly over the common aponeurosis of the extensor tendon and delimitated in most of the preparations the distal end of the tunnel of the deep radial nerve. Since the deep radial branch and the muscular branches parallel to that branch cross this part of the tendon at an obtuse angle we believe that the repeatedly discussed possibility of a dynamic nerve compression without structural influences is the triggering mechanism for the observed nerve damage.