Tibia they afford attachment to the anterior and posterior ligaments of the lateral malleolus. The medial surface -- see medial malleolus for details. Ankle fractures of the tibia have several classification systems based on location or mechanism: The tibia is supplied with blood from two sources: A nutrient artery, as the main source, and periosteal vessels derived from the anterior tibial artery. The tibia is a part of four joints; the knee, ankle, superior and inferior tibiofibular joint. In the knee the tibia forms one of the two articulations with the femur, often referred to as the "tibiofemoral components" of the
Femur the bone. Some species of whales, snakes, and other non-walking vertebrates have vestigial femurs. One of the earliest known vertebrates to have a femur is the "eusthenopteron", a prehistoric lobe-finned fish from the Late Devonian period. Structures analogous to the third trochanter are present in mammals, including some primates. In invertebrate zoology the name "femur" appears in arthropodology. The usage is not homologous with that of vertebrate anatomy; the term "femur" simply has been adopted by analogy and refers, where applicable, to the most proximal of (usually) the two longest jointed segments of the legs of the arthropoda. The two