The knee joint is the site of junction and articulation between the thigh and the leg. It is composed of three bones; the distal portion of femur, the proximal end of tibia, and the patella. These three bones are attached to one another by a series of ligaments and tendons, such as the cruciate ligaments, the menisci, fibular collateral ligament, tibial collateral ligament, capsular ligament, and the quadriceps femoral tendon and the patellar ligament. They allow the leg to fold backwards on the femur/thigh lower end, like a hinge.
The articular surfaces of the femur intercondyle are ellipsoid, with the medial condyle being more complex than the lateral one; meanwhile, the patellar surface is located right on the lower anterior surface of the bone, which is called facies patellaris in Latin. The superior articular surfaces of the tibial condyles are slightly concave, and they are incongruent with the convex articular surfaces of the femur condyles. This incongruence is corrected by the interarticular cartilages called menisci (the medial meniscus and the lateral meniscus), which lie on top of the tibia, being fused to the articular capsule.
The anterior and the posterior cruciate ligaments, which form a cross, provides the knee joint with rotary stability. The anterior cruciate ligament extends forwards from the lateral condyle of femur to the anterior intercondylar region of tibia. The posterior cruciate ligament, on the other hand, runs backwards from the medial surface of medial femoral condyle to the posterior intercondylar area of tibia, crossing anterior C. L.
Below, anterior view of right knee joint, exhibiting its ligaments and tendons.
Below, a radiographic picture of the knee joint region. Here, ligaments and tendons cannot be seen. Only the distal portion of femur and the proximal extremity of tibia and fibula can be observed.
