Bird feet and legs only a small extension of the cnemial crest. In grebes both a normal patella and an extension of the cnemial crest are found. The fibula is reduced and adheres extensively to the tibia, usually reaching two-thirds of its length. Only penguins have full-length fibulae. The bird knee joint between the femur and tibia (or rather tibiotarsus) points forwards, but is hidden within the feathers. The backward-pointing "heel" (ankle) that is easily visible is a joint between the tibiotarsus and tarsometatarsus. The joint inside the tarsus occurs also in some reptiles. It is worth noting here that the name "thick knee"
Stifle joint the joint into two functional units—the 'femoromeniscal joint' for flexion/extension movements and the 'meniscotibial joint' for rotation—a function analogous to that of the disc dividing the temporomandibular (jaw) joint. The menisci also contain nerve endings which are used to assist in proprioreception. The menisci are attached via a variety of ligaments: two meniscotibial ligaments for each meniscus, the meniscofemoral from the lateral meniscus to the femur, the meniscocollateral from the medial meniscus to the medial collateral ligament, and the transverse ligament (or intermeniscal) which runs between the two menisci. There are between one and four sesamoid bones associated with the