The posterior cruciate ligament (Ligamentum cruciatum posterius) connects the thigh bone (femur) and tibia. The posterior cruciate ligament serves as part of the ligamentous apparatus of the knee to stabilize the knee joint (Articulatio genus). Like the ligament structures of all joints, the posterior cruciate ligament consists mainly of collagen fibers, i.e. connective tissue.
Although the posterior cruciate ligament belongs to the holding apparatus of the knee joint, it is actually located outside the joint surface of the knee. It is separated from the joint cavity by a mucous membrane bag. The posterior cruciate ligament extends from the inner knot of the thigh bone (condyylus medialis) from the front/top/inside to the rear surface of the elevation in the middle of the tibial plateau, i.e. backwards/down/outside.
This means that it runs in exactly the opposite direction to the anterior cruciate ligament, thus achieving increased stability. Since the joint surface (the condyles) of the femur is significantly larger than the joint surface (tibial plateau) of the tibia, the knee joint requires a strong ligament stabilization. The cruciate ligaments serve as a passive guide during the movements of the knee joint and limit the extension in the knee joint.
The rear cruciate ligament also prevents the shin bone from sliding backwards. The rear cruciate ligament also makes rotation in the knee joint more difficult. At least parts of the cruciate ligaments are tightened in all positions of the knee joint.
This makes clear their important function in stabilizing the knee joint. A rupture (tear) of the posterior cruciate ligament (posterior cruciate ligament rupture) is relatively rare in isolation. It is usually a component of complex traumas caused by massive external violence.
The rupture of the rear cruciate ligament is also called dashboard injury because it is more common in car accidents in which the lower legs are pressed against the dashboard. A rupture of the rear cruciate ligament is accompanied by pain and instability of the knee joint. In the case of a rupture, this instability is impressively demonstrated by the so-called “drawer phenomenon”: with an angled leg and fixed thigh, the lower leg can be pushed backwards like a drawer.
