Resorption of the undersurface of the distal clavicle in rheumatoid arthritis.

An elongated erosion on the undersurface of the distal clavicle, adjacent to the coracoid process, may be seen in the shoulder of a patient with rheumatoid arthritis. This finding is apparently related to inflammatory changes in the coracoclavicular ligament. Such an erosion may occur with or without additional radiographic alterations and, although not entirely specific, suggests rheumatoid arthritis.