Posterior Cruciate Ligament (PCL) Injuries
What Is It?
The posterior cruciate ligament (PCL) and the anterior cruciate ligament (ACL) are two tough bands of fibrous tissue that connect the thighbone (femur) and the large bone of the lower leg (tibia) at the knee joint. Together, the ACL and PCL bridge the inside of the knee joint, forming an "X" pattern that stabilizes the knee against front-to-back and back-to-front forces. In particular, the PCL prevents the lower leg from slipping too far back in relation to the upper leg, especially when the knee is flexed (bent).
A PCL injury is a sprain (stretch or tear of a ligament). The PCL most often is sprained when the front of the knee hits the dashboard during an automobile accident. During sports activities, the PCL also can tear when an athlete falls forward and lands hard on a bent knee, which is common in football, basketball, soccer and especially rugby.
Like other types of sprains, PCL injuries are classified according to a traditional grading system.