A ligament is a tough band of white, fibrous, slightly elastic tissue.

This is an essential part of the skeletal joints; binding the bone ends together to prevent dislocation and excessive movement that might cause breakage. Ligaments also support many internal organs; including the uterus, the bladder, the liver, and the diaphragm and helps in shaping and supporting the breasts. Ligaments, especially those in the ankle joint and knee, are sometimes damaged by injury. A "torn" ligament usually results from twisting stress when the knee is turned while weight is on that particular leg. Minor sprains are treated with ice, bandages and sometimes physical therapy, but if the ligament is torn, the joint may be placed in a plaster cast to allow time to heal or it may require surgical repairs.

If a ligament is made up of several thick bands of fibrous branches, it is called a "collateral ligament."

The word "ligament" comes from the Latin word, "ligamentum," meaning a band or tie.