Some vagaries of the medial epicondyle.

Roentgenographic data on the maturing epiphysis of the medial epicondyle of the humerus are prone to misinterpretation for the following reasons. First, fractures of the medial epicondyle may not be associated with joint effusion or metaphyseal avulsion fragments. Second, in the medial epicondyle the center of ossification, which lies posteromedial to the distal end of the humerus and is the last of the elbow epiphyses to unite with the humerus, may be quite distant from the humeral metaphysis, and differentiation of this normal characteristic from minimum avulsion is necessary. Also, multicentric ossification, although uncommon, will give the epiphysis a fragmented appearance. Finally, just before ossification of the medial epicondylar epiphysis, on its metaphyseal surface on the distal end of the humerus a sharp, straight sclerotic edge develops.