Thumb Arthritis

Arthritis in your thumb occurs when the protective cartilage cushioning your thumb joints starts to wear out and deteriorate. This type of arthritis is called osteoarthritis. In your thumb, osteoarthritis develops most often in the basal joint at the base of your thumb. This is also called your thumb carpometacarpal (CMC) joint. The CMC joint is located near your wrist at the fleshy part of your thumb. It helps your thumb move around in different directions so you can grip things in your hand.

Thumb arthritis is the second-most common kind of arthritis that affects your hand, after arthritis that affects the last joint in your fingers.

Another name for thumb arthritis is basal joint arthritis.