Unilateral os hamuli proprium simulating a fracture of the hook of the hamate: a case report.

The authors present a case of os hamuli proprium, a congenital anomaly of the hook of the hamate. A unilateral presentation of this anomaly is rare--this is the first to be reported in the literature. The lesion could easily be mistaken for a fracture of the hook of the hamate. Radiologists and orthopaedists should be aware of the possibility of such a misdiagnosis.