During my middle school years, I recall hearing that someone had injured their ACL. At the time, I could discern that this “ACL” was in the knee but had no idea what its purpose was or where it was located. I’m fortunate to have a father who is a physical therapist that took the time to explain the function and the anatomy of the ACL to me. Most do not have this convenience and only know that an ACL injury “is bad” or is “season ending”. Additionally, many are unfamiliar with the other ligaments of the knee and may be caught off guard when hearing that a knee ligament injury occurred to the MCL, PCL or LCL but not the ACL. The purpose of this blog post is to provide a very basic explanation of the location and function of the major ligaments of the knee starting with the ACL. The anterior cruciate ligament attaches to the anterior portion of the femur and tibia thus playing a role in joining the two bones. The primary role of the ACL is to limit rotation and forward motion of the tibia. The posterior cruciate ligament is located on the posterior portions of the femur and tibia and serves to connect the two bones. The PCL limits backwards movement of the tibia. The medial cruciate ligament is located on the medial side of the knee and connects the femur to the tibia. The MCL serves to limit valgus movement of the knee (imagine someone pushing your knee inwards from the side while you were standing straight up. The MCL limits this). The lateral cruciate ligament is located on the lateral portion of the knee and connects the femur to the tibia. The LCL works to prevent varus movement of the knee (exactly the opposite function of the MCL). We see that the ligaments of the knee work opposite of each other to achieve total knee stabilization. Let us know what you think about this blog post by leaving a comment or by sending a tweet our way!