Sprains and strains are types of minor injuries to the soft tissues and connective tissues of the musculoskeletal system. Sprains usually refer to injuries to ligaments, but sometimes to other connective tissues, such as tendons and the capsules surrounding joints. Strains usually refer to injuries to muscles or to the areas where muscles become tendons. 

Sprains and strains may occur together, and occasionally are quite severe, requiring immobilization of the body part in a rigid cast for weeks, long-term rehabilitation programs, and sometimes surgery.