Functional disturbance of the inferior radio-ulnar joint due to hypoplasia of the lower end of the ulna.
Variations in the difference between the ulnar and radial length are described as the ulnar variance. The frequency of these variants are studied in a Greek population. It was found that the commonest is the neutral variant (51.7%) and less common the minus variant (33.6%). Five cases of an extreme bilateral minus variant is also reported. These cases were accompanied, except the hypoplasia of the ulna, by increased obliquity of the radial lower epiphysis. Functional disturbance from this abnormality was found to be minimal.