A ligament is a tough band of connective tissue that connects bones to other bones at a joint. They help stabilize and support the joints, allowing for movement while preventing excessive motion that could lead to injury. Ligaments are made primarily of collagen, which gives them strength and flexibility. In the human body, there are several important ligaments, such as the anterior cruciate ligament (ACL) in the knee, which plays a crucial role in maintaining stability during activities like running and jumping. Injuries to ligaments, such as sprains, can occur from sudden movements or overexertion, often requiring rest and rehabilitation.