A sprain, also known as a torn ligament, is the stretching or tearing of ligaments within a joint, often caused by an injury abruptly forcing the joint beyond its functional range of motion. Ligaments are tough, inelastic fibers made of collagen that connect two or more bones to form a joint and are important for joint stability and proprioception, which is the body's sense of limb position and movement. Sprains can occur at any joint but most commonly occur in the ankle, knee, or wrist. An equivalent injury to a muscle or tendon is known as a strain.