Knee bones and ligaments. Artwork of a frontal view of the knee joint, showing bones, ligaments, tendons, and cartilage. The bones are the femur (thigh bone, top), patella (knee-cap, upper centre), and the lower leg bones, the tibia (lower centre) and the fibula (lower right). The quadriceps femoris muscle tendon passes over the patella, becoming the patellar ligament of the tibia. At left and right are the medial and fibular collateral ligaments. Two short ligaments (centre) join femur and tibia: the posterior and anterior cruciate ligaments. The menisci (grey) are cartilage pads cushioning the joint. Posterior thigh muscles (hamstrings, red) are at upper left.