The surgical anatomy of the radial nerve and the triceps aponeurosis.

The radial nerve passes around the posterior aspect of the humerus where it is prone to injury in both humeral fractures and surgical exploration of this region. We examined 55 cadaveric limbs to determine whether the exact position of the radial nerve could be reliably predicted on the basis of superficial anatomical markings. We found that when there is considerable variability in the position of the nerve in relation to the lateral epicondyle, the nerve consistently passed adjacent to the lateral border of the triceps aponeurosis at a distance of 22-27 (+/-2) mm. It was never found to be closer than 13 (+/-1) mm to the aponeurosis. The lateral border of the triceps aponeurosis is easy to identify and our findings may help avoid iatrogenic injury to the radial nerve during exploration.