Which condition is characterized by inflammation of the synovial membrane?

Rheumatoid arthritis is characterized by inflammation of the synovial membrane, which lines the joints. This autoimmune condition leads to the abnormal immune response that attacks the synovium, resulting in swelling, pain, and deterioration of the joint structures. Typically, this inflammation not only affects the synovial membrane but can also extend to the cartilage and surrounding tissues, thereby causing joint damage and deformities over time. The chronic inflammation seen in rheumatoid arthritis distinguishes it from other musculoskeletal conditions, which may involve different tissues or mechanisms.

In contrast, conditions like sciatica primarily involve nerve pain due to irritation of the sciatic nerve, a meniscus tear refers to damage to the cartilage in the knee joint, and tendinitis is an inflammation of a tendon, not the synovial membrane. Each of these conditions affects different structures in the musculoskeletal system, but they do not center on synovial membrane inflammation like rheumatoid arthritis does.