PROGRESS IN ORTHOPEDIC SURGERY FOR 1946 A Review Prepared by an Editorial Board of the American Academy of Orthopaedic Surgeons: II. CONDITIONS INVOLVING THE KNEE JOINT

Anatomy and Physiology.  —Haxton,⁶⁰ by using tensometers, found that the leverage of action of the extensor muscles on the knee and elbow becomes greater as the joints are extended from the flexed position. The leverage is greater in the knee, and it extends over a greater range of movement of the joint. This is because of the anatomic features of the joints which determine the relationship of the axis of the joint to the extensor tendons, for example, in the knee the combination of the patella and the posterior relationship of the femoral condyles and in the elbow the posterior projection of the olecranon process. Disadvantages of the mechanism of movement are discussed.In a short article, Brantigan and Voshell⁶¹ described the relationship of the ligament of Humphrey to the ligament of Wrisberg. The ligament of Wrisberg is behind the posterior cruciate ligament, while the ligament of Humphrey