Tuberosity of the tibia of the large structure that acts as a lever to extend the knee-joint and prevents the knee from collapsing when the foot strikes the ground. The two ligaments, the patella, and the tibial tuberosity are all superficial, easily palpable structures. Tibial tuberosity fractures are infrequent fractures, most common in adolescents. In running and jumping movements, extreme contraction of the knee extensors can result in avulsion fractures of the tuberosity apophysis. A cast is all that is required if the fragment is not displaced from its normal position on the tibia. However, if the fracture fragment is displaced, then surgery is
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