What is the purpose of the anterior cruciate ligament (ACL)?

The anterior cruciate ligament (ACL) plays a crucial role in knee stability and function. One of its primary purposes is to prevent anterior displacement of the tibia on the femur, which is essential for maintaining proper alignment and movement during activities that involve walking, running, or jumping. When the ACL is intact, it helps control the forward movement of the tibia relative to the femur, which is particularly important during activities that involve sudden stops or changes in direction.

If the ACL becomes injured or torn, this mechanism is compromised, leading to instability in the knee joint and an increased risk of further injury. This function of the ACL is fundamental to ensuring that the lower extremity can perform movements effectively and safely, making it a key component of the knee's structural integrity and mobility.