Ligament

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In anatomy, the term ligament is used to denote three different types of structures:

Fibrous tissue that connects bones (or two different parts of a single bone)
A fold of peritoneum or other membrane
The remnants of a tubular structure from the fetal period of life

1 Fibrous ligaments
2 Peritoneal ligaments
3 Remnants of fetal structures
4 List of major fibrous ligaments
5 External links

[edit] Fibrous ligaments

In its most common use, a ligament is a short band of tough fibrous connective tissue composed mainly of long, stringy collagen fibres. Ligaments connect bones to other bones to form a joint. (They do not connect muscles to bones; that is the function of tendons.) Some ligaments limit the mobility of articulations, or prevent certain movements altogether.

Capsular ligaments are part of the articular capsule that surrounds synovial joints. They act as mechanical reinforcements. Extra-capsular ligaments join bones together and provide joint stability.

Ligaments are slightly elastic; when under tension, they gradually lengthen. This is one reason why dislocated joints must be set as quickly as possible: if the ligaments lengthen too much, then the joint will be weakened, becoming prone to future dislocations. Athletes, gymnasts, dancers, and martial artists perform stretching exercises to lengthen their ligaments, making their joints more supple. The term double-jointed refers to people who have more elastic ligaments, allowing their joints to stretch and contort further. The medical term for describing such double-jointed persons is hyperlaxity and double-jointed is a synonym of hyperlax.

The study of ligaments is known as desmology.

The consequence of a broken ligament can be instability of the joint. Not all broken ligaments need surgery, but if surgery is needed to stabilise the joint, the broken ligament can be joined. Scar tissue may prevent this. If it is not possible to fix the broken ligament, other procedures such as the Brunelli Procedure can correct the instability. Instability of a joint can over time lead to wear of the cartilage and eventually to osteoarthritis.

[edit] Peritoneal ligaments

Certain folds of peritoneum are referred to as ligaments. For example, the hepatoduodenal ligament is the peritoneum that surrounds the hepatic portal vein and other vessels as they travel from the duodenum to the liver. The broad ligament of the uterus is also a fold of peritoneum.

[edit] Remnants of fetal structures

Certain tubular structures from the fetal period are referred to as ligaments after they close up and turn into cord-like structures. For example, the ligamentum arteriosum is the closed-up adult version of the ductus arteriosus.