Ligament vs Tendon

The musculoskeletal system of organisms is what assists in the movement of the locomotive organs - the limbs - as well as other parts of the body as and when required. The musculoskeletal system is composed of the bones and muscles of the organism and these various bones are connected to each other and to muscles with the help of structures known as connective tissues. Ligaments and tendons are the two chief connective tissues besides fascia. The major difference with relation to ligament vs tendon is the fact that ligaments connect two separate bones to each other whereas tendons connect muscles to bones. Fascia connect muscles to muscles. Let's look at each of these connective tissues separately in order to understand the structural as well as functional differences between ligaments and tendons better.

What is a Ligament?

Ligaments are fibrous connective tissues that connects one bone to another. Being connective tissues that facilitate movement, ligaments are extremely elastic to allow stretching and bending of joints and limbs for producing motion. Ligaments can be classified under three major categories - Articular Ligaments, Fetal Remnant Ligaments and Peritoneal Ligaments.

Articular Ligaments are those bone-to-bone connective tissues that connect bones to form joints. These ligaments are very tough and densely fibrous, which is necessary for enduring the wear and tear that is undergone by joints. These ligaments are majorly composed of very dense clusters of extremely thin collagen fibers. The ligaments that are present in the head-and-neck region (cricothyroid ligament, periodontal ligament, ocular suspensory ligament, etc.), the wrist area (dorsal radiocarpal ligament, radial collateral ligament, palmar radiocarpal ligament, ulnar radiocarpal ligament, etc.), the thoracic region (suspensory breast ligament), ligaments of the knees\ (patellar ligament, anterior cruciate ligament, caudal cruciate ligament, lateral collateral ligament, cranial cruciate ligament, posterior cruciate ligament, medial collateral ligament, etc.) and the pelvic region.

Fetal Remnant Ligaments are those ligament like structures that have remained in the organism's body since its fetal stage and have developed into ligament resembling tissues. These structures include the ligamentum venosum, ligamentum arteriosum, cord of umbilical artery and the round ligament of the liver.

Peritoneal Ligaments are folds of connective tissues that form in and around the membranous lining of the abdominal cavity. These ligaments are the hepatoduodenal ligament and the uterine ligament.

What is a Tendon?

Tendons are connective tissues having very high tensile strength which connect muscles to bones. Similar to ligaments, tendons are also chiefly composed of collagenous fibers. Tendons are structurally designed for withstanding high amounts of muscular tension and they work in conjunction with muscles to exert an inward force which is used to pull things towards the body. Besides dense collagen fibers, tendons are also composed of elastin, heavily glycosylated glycoproteins, calcium, manganese and copper.

Difference Between Ligament and Tendon

Given below are the major differences between tendons and ligaments in terms of composition, placement, functions and types of injury.

Points of Difference	Ligaments	Tendons
Composition	Clusters of small packets of soft collagen fibers	Collagen fibers, elastin, proteoglycans, copper, calcium, manganese
Placement	Between bone joints, around the abdominal cavity and uterus	Between Muscles and bones of the hands and arms, feet, legs, thighs, hips, fingers, etc.
Functions	Connects bones with bones	Connects muscles with bones
Injuries	Sprains, torn ligament	Tendonitis, Avulsion, Tenosynovitis

That was a brief snapshot with regards to major structural and functional differences between ligament vs tendon. Most injuries of these connective tissues occur due to overexertion and higher-than-normal wear and tear caused by sports and athletics as well as due to sudden, jerks or forceful, spasmodic movements. Treatment and healing process usually includes application or oral intake of pain killers and anti-inflammatory medications and complete rest to enable the tissues to recover from the damage.