Arthritis is a term for any of more than one hundred diseases that produce swelling in a joint, accompanied by pain and stiffness. The most common forms of arthritis are osteoarthritis (the degeneration of a joint) and rheumatoid arthritis ("the great crippler," inflammation of a joint that erodes bone and cartilage). Other forms include gout (caused by too much uric acid accumulating in the blood and most often affecting the big toe joint), ankylosing spondylitis (inflammation of spinal joints, mainly affecting young men), infectious arthritis (caused by invading microorganisms), and chronic Lyme arthritis (which appears in some people who contract Lyme disease). Lupus, an autoimmune disease, also has elements of arthritis, with painful and often swollen joints.

Neanderthal skeletons show signs of arthritis, as do Egyptian mummies. Ancient Greek and Roman physicians wrote detailed descriptions of arthritic conditions and methods of treatment. In fourteenth- and fifteenth-century Europe, gout...