ankylosing spondylitis

Ankylosing spondylitis, or AS, is a chronic inflammatory disease and a type of arthritis that primarily affects the spine. "Ankylosing" in medical terms means "fusing together". "Spondylo" is derived from the Greek word for "vertebra" and the ending, "itis" means inflammation, in the case of AS, of the spinal vertebrae. AS can cause inflammation between the vertebrae (the bones that make up your spine), and in the joints between the spine and hips. In some people, it may cause some of your vertebrae to fuse together, or affect other joints. AS is part of a larger grouping of arthritis-associated diseases called spondyloarthritis (SpA). The hallmark feature found in AS is the involvement of the sacroiliac (SI) joints. AS can also cause pain, stiffness and inflammation in other body areas like the shoulders, hips, ribs and small bones of the hands and feet. Ankylosing spondylitis can also affect other areas of the body like the eyes (iritis), and rarely the heart and the lungs.