The Facts
Bursitis is an inflammation of a bursa, which is a fluid-filled sac located near the bones around the joints and between muscle attachments at a joint. Their purpose is to cushion and lubricate the movement of tendons and muscle over bone.
The joint most commonly affected with bursitis is the shoulder. Other joints that may develop bursitis include the elbow, the knee (this is also known as housemaid's knee), and the base of the big toe (called a bunion). Bursitis may be acute or chronic. The chronic form tends to come and go over cycles of weeks or months.