The posterior cruciate ligament (PCL) is one of four major stabilizing ligaments in the knee. It prevents the tibia from moving backwards beneath the femur and plays an important role in stabilizing rotational motion.
Together with the anterior cruciate ligament (ACL), the PCL prevents the knee from buckling and giving way during side-stepping and pivoting motions. It is about twice as strong and thick as the ACL, and therefore tends to be injured less often. The PCL may be stretched, torn partially, or torn into two distinct portions.