Rheumatoid arthritis
Rheumatoid arthritis is a chronic, systemic
Systemic disease
Life-threatening disease redirects here.A systemic disease is one that affects a number of organs and tissues, or affects the body as a whole. Although most medical conditions will eventually involve multiple organs in advanced stage Life-threatening disease redirects here.A systemic disease is one...

 inflammatory disorder
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

 that may affect many tissues and organs, but principally attacks synovial joints. The process produces an inflammatory response of the synovium
Synovial membrane is the soft tissue found between the articular capsule and the joint cavity of synovial joints....

 (synovitis) secondary to hyperplasia
Hyperplasia means increase in number of cells/proliferation of cells. It may result in the gross enlargement of an organ and the term is sometimes mixed with benign neoplasia/ benign tumor....

 of synovial cells, excess synovial fluid, and the development of pannus
Pannus is a medical term for an abnormal layer of fibrovascular tissue or granulation tissue. Common sites for pannus formation include over the cornea, over a joint surface , or on a prosthetic heart valve...

 in the synovium. The pathology of the disease process often leads to the destruction of articular cartilage and ankylosis
Ankylosis or anchylosis is a stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint, which may be the result of injury or disease. The rigidity may be complete or partial and may be due to inflammation of the tendinous or muscular structures outside the joint or of...

 of the joints.