The knee joint has four major parts: the femur (thigh bone), the tibia, the fibula, and the patella (knee cap). Other knee structures include muscles and ligament. These structures can support, move and strengthen the knee joint.
The knee muscles include the quadriceps and the hamstrings. The quadriceps are on the front, while the hamstrings are on the back. The knee ligaments are also important, because they connect the knee joint.
The meniscal cartilage is the important soft tissue, it helps the knee bones to slide on each other. On the other hand, the knee joint also has a small fluid sac, and this helps the muscles and tendons slide.