Injuries of the medial epicondylar ossification center of the humerus.

The complex nature of the ossification centers makes elbow injuries in a child or adolescent difficult to evaluate. The medial epicondylar ossification center is involved in a significant proportion. Injuries vary from simple avulsions to wide displacement with entrapment in the elbow. When entrapment occurs, it may be mistaken for the trochlear ossification center and the true nature of the injury overlooked. Radiographic findings are presented. The anteroposterior view was found to be diagnostic in minimal or marked avulsions of the medial epicondyle because of the characteristic inferior displacement. The anteroposterior view may not always be diagnostic in cases of entrapment of the medial epicondyle; the lateral view is usually diagnostic. In elbow dislocation, the presence and position of the medial epicondyle must be ascertained. Comparison and oblique views are often of value.