Sacral rib: a rare congenital anomaly.

A 45-year-old patient reported for a follow-up visit after a motor vehicle accident with a history of vague right flank pain. He underwent a pelvic radiograph which revealed a long bony protuberance arising from the right sacral region; the appearance was consistent with a sacral rib. However due to the limited nature of his complaints the patient denied any surgical treatment.