supinator crest

Examining the skeleton, Dr. Kennedy said he saw the "hyperdevelopment" of the supinator crest on the ulna of the left forearm.

The radiohumeral articulation, however, suggests a greater mobility in pronation/supination and the bowed shaft and strong supinator crests suggest more powerful pronation/supination than in non-hominoids.

Subsequently, he studied the skeletons of Ice Age people found in central India and noted a high incidence of the same hyperdeveloped supinator crests in the right arms of the males, but not in the females.

The two planes arise in common - the superficial one by tendinous (the initial portion of the muscle is actually just tendon) and the deeper by muscular fibers - from the supinator crest of ulna, the lateral epicondyle of humerus, the radial collateral ligament, and the annular radial ligament.