What is ankylosing spondylitis (AS)?

What is ankylosing spondylitis (AS)?

Ankylosing spondylitis (pronounced ankle-oh-sing spon-dill-eye-tiss) is a form of arthritis that causes chronic (long-term) spine inflammation. Ankylosing spondylitis (AS) inflames the sacroiliac joints located between the base of the spine and pelvis. This inflammation, called sacroiliitis, is one of the first signs of AS. Inflammation often spreads to joints between the vertebrae, the bones that make up the spinal column. This condition is known as spondylitis.

Some people with AS experience severe, persistent back and hip pain and stiffness. Others have milder symptoms that come and go. Over time, new bone formations may fuse vertebrae sections together, making the spine rigid. This condition is called ankylosis.