The posterior cruciate ligament (PCL) primarily stabilizes the knee by resisting excessive posterior translation of the tibia relative to the femur.
The PCL is one of the main ligaments responsible for knee joint stability. Its primary function is to prevent the tibia (shin bone) from sliding backward under the femur (thigh bone). In addition to preventing posterior tibial translation, the PCL also plays a role in controlling rotation, particularly when the knee is flexed between 90° and 120°.
Here's a breakdown of how the PCL provides stability:
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Resists Posterior Tibial Translation: The PCL's strong, thick fibers directly oppose the tendency of the tibia to move backward in relation to the femur. This is especially important during activities that place stress on the knee, such as decelerating or squatting.
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Secondary Stabilizer for Rotation: While not the primary stabilizer for rotation, the PCL assists in preventing excessive rotation of the tibia on the femur, especially at higher degrees of knee flexion.
In essence, the PCL acts as a crucial anchor, preventing the tibia from sliding too far backward and contributing to overall knee stability, especially during high-stress activities.
