Any condition of joints of the limbs or spine associated with inflammatory or structural change. It is distinguished from ARTHRALGIA which simply means joint pain. The two main categories of arthritis are osteoarthritis, in which the primary change is thought of as mechanical failure of articular cartilage; and rheumatoid arthritis, in which the primary problem is a chronic inflammation of the synovial lining of joints, tendon sheaths and bursae. Other, less common forms of inflammatory arthritis include psoriatic arthritis, Reiter's syndrome, colitic arthritis and Behçet's syndrome. Spondyloarthritis refers to an inflammatory arthritis with involvement of the spine and is often associated with the HLA B27 tissue type. (See OSTEOARTHRITIS; RHEUMATOID ARTHRITIS; RHEUMATIC FEVER.)