Some vagaries of the capitellum.

The capitellum is the first epiphyseal center of the elbow to ossify. Its normal position is easily subject to misinterpretation as a separation fracture because: (1) the ossification center for the capitellum is situated anteriorly, (2) it is often tilted downward during development, and (3) its epiphysis tends to be wider posteriorly than anteriorly. The capitellum frequently fuses with the trochlea and lateral epicondyle before uniting with the humerus. We reviewed the normal anatomical configuration of the elbow. Some useful methods for evaluating the position of the normally situated and minimally displaced capitellum and distal end of the humerus are presented.