Abstract

The active muscles and passive ligaments combine to form an anatomically precise structure which stabilizes the knee joint in all three planes. A. Stability in the sagittal plane is largely assured by the cruciate ligaments and by mutually antagonistic action of the flexor and extensor muscles. B. Stability in the coronal plane is mainly sustained by the active and passive structures on the medial and lateral sides of the knee joint (the collateral ligaments, the lower ends of the sartorius, gracilis and semitendinosus muscles and the lower ends of biceps femoris and the fascia lata). C. Rotatory stability in the horizontal plane is maintained by the synergistic action of the active and passive elements in such a way that the structures around the knee joint may be thought of as an antitorsional system. Verf.-Referat