'Olecranon bursitis' (also informally known as 'student's elbow';, 'baker's elbow';, 'swellbow';, or 'water on the elbow' is a condition characterised by pain, redness and swelling around the olecranon, caused by inflammation of the elbow's bursa. This bursa is located just over the extensor aspect of the extreme proximal end of the ulna. In common with other bursae, it is impalpable and contains only a very small amount of fluid in its normal state, and fulfills the function of facilitating the joint's movement by enabling anatomical structures to glide more easily over each other.