Hand surgeon Steven H. Goldberg, MD explains olecranon bursitis:
Olecranon bursitis is a common problem that causes pain and swelling near the point of the elbow. There are several causes of olecranon bursitis. In some people we never know what causes this problem. In other people it can begin with trauma or injury to the area. Blood can fill the area, inflammation can occur, or infection can cause the problem. Infections can be either sudden or can slowly grow and become very long lasting. Depending on the cause of the bursitis, the treatment may vary considerably and may just include observation or could require surgery to clean the area.
The olecranon is the pointy part of your elbow. The olecranon bursa is one of many bursas in your body. A bursa is a type of tissue below the skin that produces fluid and helps the skin or deeper tissues move across areas where a lot of motion occurs. The olecranon bursa, for example, helps the skin slide over the olecranon as you bend or straighten the elbow. Other areas where there are bursae include the subacromial and subdeltoid (shoulder) bursa, the greater trochanteric (hip) bursa, and the prepatellar (knee) bursa. Bursitis can occur at any of these areas.