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"
Tuberosity of the tibia necessary to allow for normal function. Tenderness in the tibial tuberosity can arise from Osgood-Schlatter’s syndrome or deep infrapatellar bursitis. A bony prominence on the tibial tuberosity can be the result of ongoing Osgood-Schlatter’s irritation in an adolescent with open growth plates, or what remains of Osgood-Schlatter’s in adults. Tuberosity of the tibia The tuberosity of the tibia or tibial tuberosity or tibial tubercle is a large oblong elevation on the proximal, anterior aspect of the tibia, just below where the anterior surfaces of the lateral and medial tibial condyles end. It gives attachment to the patellar ligament, which attaches