The anatomy of the proximal radioulnar joint.

This study is an anatomic investigation to define the architecture of and the stabilizing structures for the proximal radioulnar joint. Ten fresh-frozen cadaver elbows were dissected. Measurements of the radial head, annular ligament, radial fossa of the ulna, and interosseous membrane were made and were correlated to clinical observations of elbow stability. Sequential transection of the soft tissue constraints of the proximal radioulnar joint demonstrated the annular ligament and the central band of the interosseous membrane to be the main stabilizers in pronation and the central band to be the significant stabilizer in supination. Eccentric loading of the joint was noted on anterior-posterior shifting of the radial head during forearm rotation. The clinical relevance of these observations in relation to radial head dislocation, fracture pattern, and elbow stability is discussed.