Anatomy, Bony Pelvis and Lower Limb: Knee Posterior Cruciate Ligament

Excerpt

The posterior cruciate ligament (PCL) derives its name from its attachment to the posterior aspect of the tibia and the 'cross' structure formed with the anterior cruciate ligament (ACL) inside the joint capsule of the knee. Like the other ligaments in the knee, the function of the PCL is to provide stability to the knee joint. The PCL is one of two cruciate ligaments of the knee that acts primarily to restrict posterior tibial translation relative to the femur. The PCL is the functional counterpart of the ACL, which prevents excessive anterior tibial translation relative to the femur. Together, the cruciate ligaments act as static stabilizers that hold the knee joint together throughout its full range of motion.

The PCL is the largest and strongest ligament in the knee and consists of two bundles: the anterolateral bundle and the posteromedial bundle. The PCL is susceptible to injury by a posterior force to the proximal tibia when the knee is in the flexed position. For example, in motor vehicle collisions with anterior impact, the driver's knee hits the dashboard causing posterior displacement of the proximal tibia and injuring the PCL. PCL injuries rarely occur in isolation and most commonly involve damage to other ligaments of the knee as well. The posterior drawer test is useful to assess the stability of the PCL clinically, and magnetic resonance imaging can confirm a PCL injury or tear.