The ACL, or Anterior Cruciate Ligament, is one of the four major ligaments in your knee that helps stabilize it. It connects the femur to the tibia and is important for knee stability, particularly in sports like soccer, football, basketball, and tennis. An ACL injury occurs when this ligament is stretched too far or torn, and is common in athletes, weekend warriors, or anyone who enjoys physical activity. Read on to learn more about ACL injuries, including the types of tears, causes, symptoms, and treatments.