Overview

What Is Ankylosing Spondylitis?

Ankylosing spondylitis (AS) is a type of arthritis that affects the spine. AS is a disease that causes inflammation of the spine and large joints, resulting in stiffness and pain.

The disease may result in erosion and the formation of bony bridges at the joint between the spine and the hip bone (the sacroiliac joint) and between vertebrae in the spine, fusing those bones. In addition, bones in the chest may fuse.

AS is more common among young people between ages 17 and 35, but it can occur in children and older adults as well. The disease affects young men two to three times more than women, and it tends to run in families.