Sternocostal joints. Anatomic, radiographic and pathologic features in adult cadavers.

Using radiographic-pathologic correlation, we studied the sternocostal joints derived from 27 consecutive cadavers and one additional cadaver with rheumatoid arthritis. Radiographic findings that were tabulated included joint space narrowing, sternal or costal osteophytes, articular calcification, vacuum phenomena, and the degree of ossification of the costal cartilages. The first sternocostal joint could be classified as either a synchondrosis or synostosis in every instance; however, a joint cavity lateral to the first sternocostal joint represented a normal variation and was seen radiographically in 10 specimens. The second sternocostal joint was synovial in type and intimately related to the manubriosternal joint; cavitation within this joint was present bilaterally in 36% of our specimens. Degenerative changes in the sternocostal articulations were characterized much more frequently by sternal osteophytes than by costal osteophytes or joint space narrowing. Calcification compatible with chondrocalcinosis was observed in two cadavers. Radiographic and pathologic evidence of synovial inflammation was evident in the sternocostal joints of the rheumatoid specimen.