The function and mobility of each joint depends on its anatomical design. Joints that permit no movement or slight movement are common in the axial skeleton where basic structural support and protection is expected. Joints that are freely moveable are common in the appendicular skeleton where mobility is required. Is known as articulation.
The tibial collateral ligament reinforces the medial side of the knee joint and the fibular collateral ligament reinforces the lateral side of the knee joint. Two popliteal ligaments reinforce the posterior side of the knee joint.
