Arthritis is a joint disorder featuring inflammation. A joint is an area of the body where two different bones meet. A joint functions to move the body parts connected by its bones. Arthritis literally means inflammation of one or more joints.Arthritis is frequently accompanied by joint pain. Joint pain is referred to as arthralgia. The causes of arthritis depend on the form of arthritis. Causes include injury (leading to osteoarthritis), abnormal metabolism (such as gout and pseudogout), inheritance, infections, and unclear reasons (such as rheumatoid arthritis and systemic lupus erythematosus).