A patient with rheumatoid arthritis is likely to show TMJ changes. Which component is affected FIRST in the disease process?

Correct answer: C. The synovial membrane, with secondary destruction of the articular cartilage and condyle

• A. The coronoid process is an extra-articular muscular attachment site and is not part of the TMJ articulation.
• B. Muscle insertions are not the primary target of RA; this is a joint-lining disease.
• C. CORRECT. Rheumatoid arthritis is a SYNOVIAL disease. Inflamed synovium forms a pannus that then erodes the ARTICULAR CARTILAGE and, later, the underlying condylar bone — producing the classic radiographic picture of a flattened, eroded, 'sharpened pencil' condyle and, in advanced cases, an anterior open bite from bilateral condylar resorption.
• D. Retrodiscal tissue can become inflamed secondarily, but the disease does not spare the articulating surfaces — cartilage and bone destruction is the defining feature.

Note: Source keyed 'articular cartilage,' which is the correct articular TARGET. The initiating tissue is the synovium — both framings appear on exams, so know the sequence: synovium → pannus → cartilage → bone.