leg

Generally, the whole of the hind limb; anatomically the portion between the knee and the ankle. The anatomy of the hind limb is similar in all mammals. The thigh has one main bone, the femur, which also forms part of the hip joint and the knee joint. The leg proper contains two bones, the larger tibia (shin bone) and the smaller fibula. The upper part of the tibia forms, with the lower part of the femur, and with the patella (knee-cap), the knee joint; but both tibia and fibula enter into the formation of the ankle joint. The main difference in structure of the hind limb in mammals compared with lower vertebrates is that in the course of evolution it has rotated inwards. The main arterial blood supply of the leg is from the common femoral artery; the main nerve supply is the great sciatic nerve and its branches.