Arthritis is the name for irritation in a joint , which often becomes swollen, painful, and stiff.
The joint irritation that causes arthritis can occur for many reasons. Often the lining of the joint, the synovium, becomes inflamed . It reacts by producing extra synovial fluid , resulting in a swollen joint. The smooth white surface of the joint, the hyaline cartilage, can become thin, worn, and rough. Any joint in the body can be affected by one or another form of arthritis.