The skin on the inside of the elbow is the olecranal skin. Bursae are sacs of fluid that protect the elbow joint, which is formed by the olecranon bone and is an extension of the ulna.
The bursa resides within the olecranal skin and on top of the olecranon bone. It protects the bone from impacts and stress, and it reduces friction during everyday movement of the arm. The bursa can become infected or inflamed if the applied pressure is too great or persistent. When the inflammation is severe, a temporary supportive device, such as a cast, is required, and a medical examination might also be necessary.