What is the MCL and what are the types of MCL injury?

The posterior cruciate ligament is one of the cruciates in the middle of the knee along with the anterior cruciate ligament.  It is less commonly injured than the ACL.  Its main function is to stop posterior translation or backwards movement of the tibia on the femur.  It is most commonly injured in dashboard injuries and during road traffic accidents when the flexed knees of the passenger hit the dashboard and cause a forceful backward movement of the tibia resulting in a PCL rupture.  It can however be injured in other mechanisms.

What is the PCL and what are the types of PCL injury?

The posterior cruciate ligament is one of the cruciates in the middle of the knee along with the anterior cruciate ligament.  It is less commonly injured than the ACL.  Its main function is to stop posterior translation or backwards movement of the tibia on the femur.  It is most commonly injured in dashboard injuries and during road traffic accidents when the flexed knees of the passenger hit the dashboard and cause a forceful backward movement of the tibia resulting in a PCL rupture.  It can however be injured in other mechanisms.