Ulnar hemimelia: a report of four cases.

Ulnar hemimelia is a very rare skeletal abnormality characterized by the total or partial absence of the ulna. It is reported to occur in approximately 1 per 150,000 live births. Some shortening of the forearm, radial bowing, and tendency of the hand to drift to the ulnar side of the wrist usually accompany ulnar hemimelia. Other skeletal anomalies such as humeroradial synostosis, radial head dislocation, carpal or metacarpal coalition, and digital abnormalities may also be seen in cases of ulnar hemimelia. The patients may be asymptomatic in the presence of an isolated mild ulnar deficiency. On the other hand, cases of prominent ulnar deficiency accompanied by complex upper limb abnormalities leading to severe disability may also be observed. We herein present four patients with varying degrees of ulnar hemimelia. Our first case had an isolated ulnar hemimelia, whereas the other three had additional upper limb abnormalities of different types.