The muscles, bursae, tendons, and bones must be healthy and functioning correctly for the body to move normally. Muscles, which contract to produce movement, are connected to the bones by tendons. Bursae are flat sacs containing joint (synovial) fluid. They reduce friction in areas where skin, muscles, tendons, and ligaments rub over bones. (See also Biology of the Musculoskeletal System.)
Often, muscles, bursae, and tendons are injured during sports activities. Injury, overuse, infection, and occasionally disease can temporarily or permanently damage these structures. Damage can cause pain, limit control over movement, and reduce the normal range of motion.
Disorders of the muscles, bursae, and tendons include