Some vagaries of the lateral epicondyle.

The early roentgenographic characteristics of ossification of the epiphysis of the normal lateral epicondyle may be misinterpreted as being due to trauma. This is primarily due to the shape of the lateral epicondyle and its apparent separation from the associated metaphysis. The following points are noted. (1) The distal part of the epiphysis fuses with the capitellum before the proximal part unites with the adjacent humerus. This frequently results in the physis appearing like a fracture. (2) The epiphysis forms the most distal part of the lateral supracondylar ridge of the humerus. (3) Ossification of the epiphysis begins at the level of the capitellar physis and proceeds first to a typical silver shape and then to a triangular shape. To assist in distinguishing between the roentgenographic appearance of normal ossification and that of a fracture of a lateral epicondyle, various fractures involving the lateral epicondylar epiphysis, the capitellum, and the associated metaphyses are discussed.