What is a Bursa?
In many areas of the body, muscles and tendons must slide over and against one another during movement. At each of these places there is a bursa, which is a small sac of lubricating fluid, to help the muscles and tendons move without friction. When the bursa sac becomes inflamed, pain can result each time the tendon has to move over the bone. The pain may eventually be present at rest and may even cause a problem while sleeping.