Bursitis of the elbow. X-ray of the arm of a 59 year old man with olecranon bursitis. Bursitis is inflammation of a bursa, a fluid-filled sac that cushions and lubricates areas where tissues, such as muscles and tendons, move over bone. There are many bursae in the body; the olecranon bursa is over the point of the elbow. This case has been caused by a bone spur, or osteophyte (at base of elbow) that has put prolonged pressure on the bursa. Inflammation makes normal movement painful. Treatment is with rest and anti-inflammatory drugs. In severe recurrent cases the spur may be surgically removed.