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.