“Cross-shaped” in Latin. In the knee joint are two ligaments that cross over each other, the anterior and posterior cruciate ligaments. These ligaments help stabilize the joint, in particular, to prevent the femur (thigh bone) from slipping too far forward or backward on the tibia (leg bone). The anterior cruciate ligament (ACL) is frequently torn in football injuries when a leg firmly planted in the turf encounters a flying tackle. The player typically experiences “excruciating” pain. Excruciating, crucify and crucifixion all share the same root meaning referring to a cross and to the associated pain and suffering.