Ligaments are fibrous connective tissue located at joints within the body.
The tissue is very durable and dense in nature, made from collagenous fibers. Ligaments connect one bone to another. This feature separates them from other connective tissues such as tendons - which connect muscle to bone and fasciae which connect muscles to other muscles.
The function of ligamnets is to provide stability at the joint whilst allowing a range of movement, hence their elastic nature - they shrink when under tension, and return to their original shape when the tension is removed. This reduces the chance of dislocation at the joint.
The ligaments in the knee include the anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament and the lateral colateral ligament. They all have varying roles within the knee. The anterior cruciate ligament (commonly known as the ACL) is important in stopping the femur from sliding backward onto the tibia .