The term Arthritis was derived from the Greek words for joint (arthro) and inflammation (itis).

In fact it's an overall term used to represent what is actually over 100 forms of the condition.

There are several forms of arthritis but only a handful of common ones.

The most common forms, include osteoarthritis, a degenerative joint disease usually accompanied by age or joint trauma, septic arthritis, caused by joint infection, rheumatoid arthritis (RA) which is a chronic, systemic inflammatory disorder that often attacks synovial joints, and psoriatic arthritis another type of inflammatory arthritis affecting around 10-30% of people suffering from the chronic skin condition psoriasis, and related autoimmune diseases.

Ongoing research to improve the quality of life for people affected by arthritis is constantly producing a greater understanding of it's causes and better treatment methods.
 

Prevalence of  Arthritis Among Americans