The anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL) work together to provide stability in the knee. They cross each other and form an 'X.'

Injuries to the cruciate ligaments of the knee are typically sprains. The anterior cruciate ligament is most often stretched, or torn by a sudden twisting motion while the feet remain planted. The posterior cruciate ligament is most often injured by a direct impact, such as in soccer or football.
Injuries to the cruciate ligaments of the knee are typically sprains.

 The anterior cruciate ligament is most often stretched, or torn by a sudden twisting motion while the feet remain planted. The posterior cruciate ligament is most often injured by a direct impact, such as in soccer or football.