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"
Douzhanopterus then the fourth, which is still about 80% the length of the second. Fused entirely to the sacrum is the pelvic girdle. The portion of the pelvic girdle in front of the femoral joint appears to consist of two unfused prepubes, which are longer than they are wide. The femur is slightly curved, and the femoral head and neck form an angle of about 150° with the shaft. On the lower leg, the relatively straight tibia is about 180% the length of the femur; the fibula, which is about 45% the length of the tibia, is fused to it at