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cru·ci·ate lig·a·ments(krū'shē-āt lig'ă-mĕnts)
See also: Lachman test
cruciate ligamentstwo intracapsular ligaments of the knee, forming an X-shape, linking the femur to the tibia, strong but not elastic, which are crucial for the stability of the knee joint. The anterior cruciate ligament runs upwards, backwards and laterally from the front of the upper end of the tibia to attach to the medial aspect of the lateral femoral condyle; it limits forward movement of the tibia relative to the femur and tightens with extension at the knee. It is short and thick with a poor blood supply. The posterior cruciate ligament arises from the posterior intercondylar area of the tibia and runs forwards, upwards and medially to attach to the anterolateral surface of the medial femoral condyle. It limits backwards movement of the tibia relative to the femur and tightens with flexion at the knee. cruciate ligament injury (especially anterior) can result in a rapid accumulation of blood in the knee joint (haemarthrosis) and is often associated with damage to other structures, especially the medial meniscus. Treatment depends on the sport involved, the degree of instability and of other damage. In sportspeople complete rupture usually requires surgical repair, resulting in a lengthy (up to 9 months) rehabilitation programme, before return to sport. Disruption of only the posterior ligament may result in significant instability but may be hard to diagnose clinically. See also drawer sign, Lachman test.
cruciate ligamentspaired X-shaped intra-articular ligaments linking femur and tibia within the knee joint, passing from the tibial intercondylar area to the distal femur intercondylar fossa; both ligaments are relatively tensed throughout knee movement
anterior cruciate ligament passes upwards and backwards from anterior part of tibial intercondylar area to posterior part of medial surface of femoral lateral condyle; action: prevention of posterior slip of femur on tibial platform; becomes increasingly tense towards end of knee extension, allowing medial femoral condyle to continue to rotate on tibial platform, to lock knee joint during extension
posterior cruciate ligament passes upwards and forwards from posterior part of tibial intercondylar area to anterior part of lateral surface of femoral medial condyle; it receives slips from posterior part of lateral meniscus; action: prevention of anterior slip of femur on tibial platform