A PCL injury is a sprain or tear of the posterior cruciate ligament (PCL). The PCL is a band of tissue that crosses inside the center of the knee joint. It connects your thighbone to the bone of your lower leg. The PCL keeps your knee stable when it moves forward or backward.

A direct blow to the knee can injure your PCL. For example, the PCL can be injured in a car crash when your bent knee hits the dashboard. You can also hurt your PCL during sports, such as football, soccer, or skiing. Or you can hurt it while doing other activities if you fall on your bent knee with your foot or toes bent downward or if the front of your knee is hit.

A PCL injury can also happen if you stretch or straighten your knee beyond its normal limits (hyperextend the knee).