This largest joint in the human body forms the movable link between the femur and the tibia and consists of three sections: an inside and an outside section of the joint between the femur and the tibia (femorotibial joint). The articular space in between is occupied by pads of cartilaginous tissue (menisci). The third section of the joint lies between the knee-cap and the femur (femoropatellar joint).
All joint sections are covered with a cartilaginous layer and enclosed in a common joint capsule. The synovial membrane excretes a liquid that nurtures the cartilage; the function of the cartilage in combination with the menisci is largely comparable to that of a shock absorber. Ligament structures between the bones stabilize the joint (e.g. the cruciate ligament and the collateral ligament). Muscles and tendons ensure the movement of the joint, primarily straightening and bending. With bent knees, small rotational movements are also possible.