Abstract
1. Two cases are reported of the uncommon condition of simple anterior dislocation of the head of the ulna at the inferior radio-ulnar joint.
2. The literature concerning the condition and its treatment is reviewed.
3. The mechanism of the inferior radio-ulnar joint is discussed with particular reference to the function of the triangular fibrocartilage.
4. The mechanism of injury is discussed and a new idea of this mechanism is put forward.