Knee the cartilage both on the femur and the tibia, but on the femur, the suprapatellar bursa or recess extends the joint space proximally. The suprapatellar bursa is prevented from being pinched during extension by the articularis genus muscle. Behind, the synovial membrane is attached to the margins of the two femoral condyles which produces two extensions similar to the anterior recess. Between these two extensions, the synovial membrane passes in front of the two cruciate ligaments at the center of the joint, thus forming a pocket direct inward. Numerous bursae surround the knee joint. The largest communicative bursa is the
Vancleavea of archosaurs as well as the internal trochanter of basal archosauriforms. The midshaft of the femur is circular in cross-section. The lower portion of the femur includes both a medial condyle (which connects to the tibia) and a lateral condyle (which connects to the fibula), although neither of these knobs are particularly strongly developed. In general, the femur of Vancleavea is intermediate in structure between basal archosauriforms and archosaurs. The tibia and fibula (lower leg bones) are both slightly curved away from the center of the leg. They are also thinnest at their respective midshafts. The front edge of the