![]() Each ligament has a particular function in helping to maintain optimal knee stability. The ligaments of the knee maintain the stability of the knee. The synovial fluid which lubricates the knee joint is pushed anteriorly when the knee is in extension, posteriorly when the knee is flexed and in the semi flexed knee the fluid is under the least tension therefor being the most comfortable position if there is a joint effusion. Other structures include the infrapatellar fat pad and bursa which function as cushions to exterior forces on the knee. The synovial membrane produces synovial fluid which lubricates the knee joint. Inside this capsule is a specialized membrane known as the synovial membrane which provides nourishment to all the surrounding structures. As with all of the structures that from the knee they are under most tension therefore more stable in an extended (closed packed) position in comparison to the laxity present in a flexed position (open packed). This along side the capsule ligaments enhances she stability of the knee. The joint capsule has thick and fibrous layer superficially and thinner layers deeper. The inner non-vascularized part (white zone) receives nutrition through diffusion of synovial fluid. ĭuring the first year of life the menisci are fully vascularized but once weight bearing commences the vascularity diminishes to the outer third (red zone), the red zone being the only area having a slight ability to heal. In fact, the posterior horn of the lateral meniscus is separated entirely from the posterolateral aspect of the joint capsule by the tendon of the popliteus muscle as it descends from the lateral epicondyle of the femur. On the lateral side, the meniscus is less firmly attached to the joint capsule and has no attachment to the lateral collateral ligament (LCL). The medial meniscus is much less mobile during joint motion than the lateral meniscus owing in large part to its firm attachment to the knee joint capsule and medial collateral ligament (MCL). The menisci are connected with the tibia by coronary ligaments. This is essential as the compressive loads through the knee can reach 1-2 times body weight during gait and stair climbing and an astonishing 3-4 times body weight during running. The arrangement of the fibres in the menisci allows for axial loads to be dispersed radially decreasing the wear on the hyaline articular cartilage. ![]() They also help to guide and coordinate knee motion, making them very important stabilizers of the knee. The menisci correct the lack of congruence between the articular surfaces of tibia and femur, increase the area of contact and improve weight distribution and shock absorption. This is due to the increased size of the medial meniscus, which unfortunately leaves a large exposed area that in turn can be prone to injury. The horns of the medial meniscus are further apart and meniscus appears ‘C’ shaped, than those of the lateral one where meniscus appears more ‘O’ shaped. The surface of each meniscus is concave superiorly, providing a congruous surface to the femoral condyles and is flat inferiorly to accompany the relatively flat tibial plateau. They are crescent-shaped lamellae, each with anterior and posterior horn, and are triangular in cross-section. There are two menisci in the space between the femoral and tibial condyles. This emphasizes the importance of the other structures of the knee such as the menisci. Overall the tibiofemoral joint is a relatively unstable joint as the plateaus are slightly convex anteriorly and posteriorly. They become lodged in the intercondylar notch of the femur, adding to the stability of the joint. ![]() The two tibial condyles are separated by the intercondylar tubercles, these are two bony spines which are roughened and their role lies within knee extension. The medial tibial plateau is much longer than the lateral anteroposteriorly, and the diameter of the proximal tibia is much greater than the shaft posteriorly which is sloped at approximately 7 to 10 o to facilitate flexion of the femoral condyles on the tibia. The tibia also has 2 asymmetrical condyles (medial and lateral) of which are relatively flat, These are also known as the tibial plateau. This engages the patella in early flexion. These two condyles are separated inferiorly by the intercondylar notch although they are connected anteriorly by a small shallow groove which is known as either the femoral sulcus or the patella groove or patella surface. The distal aspect of the femur forms the proximal articulating surface for the knee, which is composed of 2 large condyles.
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