Ligaments are tough fibrous cords composed of connective tissue that contains both collagen and elastic fibers. The elastic fibers allow the ligaments to stretch to some extent. Ligaments surround joints and bind them together. They help strengthen and stabilize joints, permitting movement only in certain directions. Ligaments also connect one bone to another (such as inside the knee).
Last full review/revision July 2007 by Pekka Mooar, MD