[Observation of a distinct humeral spur formation].

A 23 year old male with a mirror right hand, duplicated ulna and aplasia of the radius is presented. A large deformity of the distal and anterior surface of the humerus was also noted. Based on clinical documentation and X-rays it was felt that this unusual bony formation probably represented a minimal rudiment of the radius and that the bone deformity at the distal end of the humerus did not represent a supracondylar humeral spur which is occasionally seen in humerus without any concommittent congenital deformities, as is nearly always seen in mammals.