Pathogenesis of discovertebral and manubriosternal joint abnormalities in rheumatoid arthritis: a cadaveric study.

The precise pathogenesis of discovertebral lesions in rheumatoid arthritis has long been debated with the emergence of 2 conflicting theories: discovertebral extension of synovial inflammation from a neighboring articulation (Luschka, costovertebral joint) and repetitive discal trauma with Schmorl's nodes. In order to address this controversy, we performed a radiographic-pathologic correlation of a rheumatoid cadaver and compared the alterations seen in the cervical and lumbar discovertebral junction; we further included an evaluation of the manubriosternal joint, another cartilaginous articulation. Our data confirmed that advanced discovertebral lesions in the cervical and lumbar spine are related primarily to endplate failure that itself is caused by apophyseal joint destruction and segmental spinal instability, although inflammatory rheumatoid lesions of the cervical intervertebral discs probably arising from the Luschka joints are also evident. Conversely, the lesions of the manubriosternal joint were produced by inflammatory changes related to the development of a synovial cavity in the articulation.