The dog stifle (knee) is anatomically very similar to a human knee. There are two long bones, the femur (thigh bone) and the tibia (shin bone), and a small bone, the patella, which articulate together. There are also four ligaments primarily responsible for the stability of the stifle – the cranial cruciate, caudal cruciate, medial collateral, and lateral collateral. Finally, there are two menisci, medial and lateral, which help act as a cushion between the femur and the tibia and help to provide congruency and further stability to the joint. The dog stifle differs from the human knee in that the top of a dog tibia has a more significant slope (tibial plateau slope or TPS) than that of a human knee.