Ligament

A ligament is a band of fibrous connective tissue that connects bones to other bones across a joint. Ligaments help stabilize joints and guide movement. They are distinct from tendons, which connect muscles to bones.

Most ligaments are composed of dense regular connective tissue rich in type I collagen arranged in parallel fibers, giving high tensile strength. Some ligaments also contain elastin and proteoglycans that provide limited elasticity and viscoelastic properties.

Function: by spanning joints, ligaments stabilize articulations, limit undesired motions, and contribute to proprioception via mechanoreceptors that sense stretch and position.

Anatomy: ligaments can be extracapsular (outside the joint capsule) or intracapsular (inside the capsule, such as the anterior and posterior cruciate ligaments in the knee).

Vascularization and healing: ligaments have relatively poor blood supply, especially in adults, which slows healing after injury. Healing often occurs with scar tissue and remodeling over months; severe injuries may require surgery or prolonged rehabilitation.

Injury: Ligament injuries are common in sports and include sprains and tears. They are graded by severity I–III. Treatment typically involves rest or immobilization, followed by controlled mobilization and physical therapy; severe tears may require surgical reconstruction.

Examples: knee ligaments such as the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL); ankle ligaments such as the anterior talofibular and calcaneofibular ligaments.