Ossific irregularities and densities near the acetabulum are often noted on radiographs that are made for the evaluation of pain in the hip in athletes. Often, these findings are normal variants that complicate the evaluation, as they may be confused with fractures. We saw a patient who had traumatic separation of the os acetabuli marginalis supenor. which is a normal secondary center of ossification along the superolateral margin of the acetabulum. To our knowledge, this lesion has not been reported previously as a cause of pain in the hip.