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.