Role of the supinator muscle in the pathophysiological mechanism of a pulled elbow.

A pulled elbow is a common childhood orthopaedic injury that is usually caused by longitudinal traction on the hand. The pathophysiological mechanism of a pulled elbow involves interposition of the annular ligament into the radiohumeral joint. Recent ultrasonographic studies have shown that both the supinator muscle and annular ligament were trapped into the radiohumeral joint. This paper discusses why pulled elbows can occur during pronation and how a pulled elbow can be reduced either by hyperpronation or supination followed by elbow flexion based on the function of the supinator muscle.