Anterior cruciate ligament: Meaning (information, definition, explanation, facts)

The anterior cruciate ligament (or ACL) is one of the four major ligaments of the knee. It connects from a posterio-lateral (back & outside) part of the femur to an anterio-medial (front & inside) part of the tibia.

Damage to the ACL frequently occurs with lateral blows to the knee (as happens with a tackle from the side in American football) and often is accompanied by injuries to the medial collateral ligament (MCL) and the medial meniscus, which is attached to the MCL; physicians are taught "...knee injuries come in threes - anterior cruciate, medial collateral, medial meniscus." A damaged ACL can be confirmed (clinically) by a physician with the anterior drawer test, the Lachman test, or an MRI.

Non-contact tears or ruptures of the ACL often occur when athletes moving quickly in one direction make a sharp or sudden change in direction (cutting). In jump sports, ACL failure has been linked to heavy or stiff landing as well as twisting or turning the knee while landing. Studies indicate that women in jumping and cutting sports such as basketball, volleyball, or football (soccer), are signifantly more prone to ACL injuries than men; this is generally believed to be due to differences between the sexes in the angle between the hip and knee, general muscular strength, and possibly training techniques.

ACL injuries are also common in Alpine skiing, partially because of improvements in boots. Today's boots have been successful in preventing many of the ankle and leg fractures once caused by accidents; however, the tradeoff has been that the stresses have been transferred to the knees, resulting in many ACL tears.