Sprain refers to damage or tearing of ligaments or a joint. Strain refers to damage or tearing of a muscle.

When too much force is applied to a joint, the ligaments that hold the bones together may be torn or damaged. This causes a sprain, and its seriousness depends on how badly the ligaments are torn. Any joint can be sprained, but the most frequently injured joints are the ankle, knee, and finger.

Strains are tears in the muscle. Sometimes called "pulled muscles," they usually occur because of overexertion or improper lifting techniques.

Children under age 8 are less likely to have sprains than are older people because their ligaments are tighter and their bones are more apt to break before a ligament tears. People who are active in sports suffer more strains and sprains than less active people. Repeated sprains in the same joint...