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Description

The knee joint is among the largest and also most complicated joints in the body. It is built by 4 skeletal and considerable network of ligaments and also muscles.

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Anatomy

Articulating Surfaces

The thigh bone (femur), the shin bone (tibia) and the kneecap (patella) articulate with tibiofemoral and patellofemoral joints. These three bones room covered in articular cartilage i beg your pardon is an extremely hard, smooth problem designed come decrease the friction forces. The patella lies in one indentation of the femur known as the intercondylar groove.<1>


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The smaller sized fibula runs alongside the tibia and also is enclosed via the remarkable tibiofibular joint is not directly associated in the knee joint, yet provides a surface for necessary muscles and also ligaments to attach to.<1><2>


The distal aspect of the femur creates the proximal articulating surface ar for the knee, i m sorry is created of 2 large condyles. The medial and also the lateral. These two condyles room separated inferiorly by the intercondylar notch although castle are linked anteriorly by a tiny shallow groove which is recognized as one of two people the femoral sulcus or the patella groove or patella surface. This engages the patella in early flexion.

The tibia also has 2 asymmetrical condyles (medial and also lateral) of i beg your pardon are relatively flat, these are also known together the tibial plateau. The medial tibial plateau is much much longer than the lateral anteroposteriorly, and the diameter that the proximal tibia is much higher than the shaft posteriorly i beg your pardon is sloped at approximately 7 come 10o come facilitate flexion that the femoral condyles ~ above the tibia.

The 2 tibial condyles are separated by the intercondylar tubercles, these space two bony spines which are roughened and also their role lies within knee extension. They end up being lodged in the intercondylar notch the the femur, adding to the security of the joint. All at once the tibiofemoral joint is a relatively unstable joint as the plateaus room slightly convex anteriorly and also posteriorly. This emphasizes the importance of the various other structures that the knee such together the menisci.

Menisci

There room two menisci in the room between the femoral and also tibial condyles. They space crescent-shaped lamellae, each v anterior and posterior horn, and also are triangle in cross-section. The surface of each meniscus is concave superiorly, offering a congruous surface to the femoral condyles and also is flat inferiorly to accompany the relatively flat tibial plateau.<3> The horns that the medial meniscus are more apart and also meniscus shows up ‘C’ shaped, 보다 those the the lateral one wherein meniscus appears much more ‘O’ shaped. This is because of the boosted size of the medial meniscus, i beg your pardon unfortunately pipeline a big exposed area the in turn deserve to be susceptible to injury.

The menisci correct the lack of congruence between the articular surfaces of tibia and femur, increase the area that contact and also improve weight distribution and shock absorption. Castle also aid to guide and coordinate knee motion, making them an extremely important stabilizers the the knee.<3>

The arrangement of the fibres in the menisci allows for axial tons to be dispersed radially to decrease the wear top top the hyaline articular cartilage. This is essential as the compressive lots through the knee deserve to reach 1-2 times human body weight during gait and stair climbing and an astonishing 3-4 times body weight during running. The menisci are associated with the tibia by coronary ligaments. The medial meniscus is much less mobile throughout joint motion than the lateral meniscus fan in big part to its firm attachment to the knee joint capsule and medial collateral ligament (MCL). On the lateral side, the meniscus is much less firmly attached come the joint capsule and has no attachments to the lateral collateral ligament (LCL). In fact, the posterior horn that the lateral meniscus is separated entirely from the posterolateral element of the share capsule through the tendon the the popliteus muscle together it descends native the lateral epicondyle the the femur.<4>


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During the very first year that life the menisci are completely vascularized yet once weight bearing commences the vascularity diminishes to the outer 3rd (red zone), the red zone gift the just area having actually a slight capability to heal. The inside non-vascularized part (white zone) receives nutrition through diffusion the synovial fluid.<3>

Ligaments & share Capsule

The joint capsule has thick and also fibrous layer superficially and also thinner layers deeper. This follow me side the capsule ligaments improves she security of the knee. Together with all of the structures that indigenous the knee they are under most tension therefore an ext stable in an extended (closed packed) place in comparison come the laxity existing in a flexed place (open packed). Inside this capsule is a devoted membrane recognized as the synovial membrane which gives nourishment to all the neighboring structures. The synovial membrane to produce synovial fluid which lubricates the knee joint. Various other structures include the infrapatellar fat pad and also bursa which role as cushions to exterior forces on the knee.

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<1> The synovial liquid which lubricates the knee share is moved anteriorly as soon as the knee is in extension, posteriorly when the knee is flexed and also in the semi flexed knee the liquid is under the the very least tension therefor being the many comfortable place if over there is a joint effusion.

The ligaments the the knee maintain the security of the knee. Every ligament has a particular duty in helping to maintain optimal knee stability.