Final answer:
Rheumatoid arthritis (RA) is an autoimmune disorder that causes inflammation, swelling, and pain in the joints, particularly affecting the synovial joints. It involves the immune system mistakenly attacking the body's own tissues, leading to joint damage and decreased mobility.
Step-by-step explanation:
Rheumatoid arthritis (RA) is a chronic autoimmune disorder known for primarily affecting the joints, specifically the synovial joints such as those found in the hands, feet, and cervical spine. In RA, the immune system, which usually protects the body by attacking pathogens, mistakenly targets the synovium—the lining of the membranes surrounding the joints. This leads to inflammation, causing the joints to become swollen, stiff, and painful. The progression of the disease can lead to the breakdown of cartilage, causing bones to rub against each other and resulting in further pain and decreased joint function. Rheumatoid arthritis is more prevalent in women, with onset commonly between 40 to 50 years of age. Diagnosis of RA is often through clinical symptoms, supplemented by imaging techniques like X-rays, MRI, and specifically arthrography, which can reveal early degenerative changes in the joint cartilage.