Ligament

From ArticleWorld

A ligament is a band of connective tissue that connects two bones or two parts of bone together. Its primary purpose is to stabilize the area around a joint although some ligaments, such as some in the pelvis, connect two aspects of the same bony structure.

Anatomy

Ligaments are made of collagen fibers that are densely interwoven to form a tough band of tissue. Fibroblasts are living cells that support the collagen fibers with the repair and maintenance they need. Elastin fibers can exist in some ligaments that need to be somewhat stretchable. These kinds of ligaments are called white connective tissue ligaments.

Ligaments often surround moveable joints and form a structure known as a joint capsule or articular capsule. Some ligaments attach two bones together but do not form a capsule. The connections between the bones of the skull are connected by minute ligamentous sheets that sometimes eventually calcify and form a fused bony structure.

Yellow elastic ligaments form a stable connection between the vertebrae in the spinal column. Ligamentous tissues exist outside of the skeletal system and are primarily found in the abdomen and pelvis. They support the liver, the diaphragm, the kidneys and the uterus. Ligaments also help form the shape of the breasts and help suspend the breast tissue.

Conditions

Ligaments support joints that sometimes become dislocated. Because ligaments are somewhat elastic, they often are over-stretched as they accommodate the dislocation. If not repaired immediately, the over-stretched ligament can become permanently elongated so that reinjury to the joint is likely. This is especially common with dislocations of the shoulder. A posterior dislocation stretches the posterior ligaments to the point where, even after the dislocation is repaired, the joint can easily dislocate again without any further trauma whatsoever.

Any ligament can rupture as a result of excessive stress around a joint. A commonly ruptured ligament is the anterior talofibular ligament in the lateral ankle. While its ability to stretch during an inversion injury (rotating inward) of the ankle, a severe injury can rupture the ligament. The anterior cruciate ligament inside the knee joint often ruptures as well. Sports injuries that result in a lateral hit to the knee can rupture this joint easily.