
These sacs, called bursae, lie between
tendons or between
tendons and bones. Without these sacs, the
tendons would rub against each other. After an injury or infection, or because of overuse, the bursae sometimes becomes inflamed. Bursitis is very common in the shoulder and the knee. Treatment for mild cases includes resting that part of the body, heat, and painkillers. Injections of medicine, or surgery, are sometimes used in more serious cases.