The knee consists of the distal femur and the proximal part of the femur (OG 7S). Xinggu (knee) broad joint is the largest synovial joint in human body, and it is also a modified hinge joint. When the knee is in the flexion position, he can rotate the knee inward and outward (3) ° and the knee also includes the bone (kneecap) and the proximal fibula. The bony surface of the knee is shallow. It's easy to touch. Xing bone and fibula are the bones of the leg. Metabony (small bone) is located in the layer. It extends from the knee to the ankle. Just as the ulna extends from the elbow along the ξ l