Ankylosing Spondylitis (AS) is a painful, progressive form of inflammatory arthritis.
It mainly affects the spine but can also affect other joints, tendons and ligaments.
Ankylosing means fusing together. Spondylitis means inflammation of the vertebrae. Both words come from the Greek language. Ankylosing Spondylitis describes the condition where some or all of the joints and bones of the spine fuse together.
Entire fusing of the spine is unusual. Many people will only have partial fusion, sometimes limited to the pelvic bones.
Other areas such as the eyes, bowel, lungs and heart can also sometimes be involved with AS.
What happens in AS
- Inflammation occurs at the site where certain ligaments or tendons attach to the bone. This area of the body is known as enthesis.
- The inflammation is followed by some erosion (wearing away) of the bone at the site of the attachment. This is known as enthesopathy.
- As the inflammation subsides, a healing process takes place and new bone develops. Movement becomes restricted where bone replaces the elastic tissue of ligaments or tendons.
- Repetition of this inflammatory process leads to further bone formation and the individual bones which make up your backbone (vertebrae) can fuse together.
The pelvis is most commonly affected first. The lower back, chest wall and neck may also become involved at different times.
AS is a very variable condition
Some people with AS have virtually no symptoms whereas others suffer more severely.
Ankylosing spondylititis and spondylosis
These two conditions do sound very similar but are actually very different.
While ankylosing spondylitis is a form of inflammatory arthritis, spondylosis is a medical term for the general wear and tear that occurs in the joints and bones of the spine as people get older.
Cervical spondylosis specifically refers to wear and tear occuring in the section of spine in the neck (the cervical spine). It causes periods of stiffness and pain in the neck that may spread to the shoulders and the base of the skull. The pain and symptoms vary from one person to another but usually follow a pattern of good days and bad days.
Spondylosis is an age related condition. It is estimated that almost everyone will have some symptoms of cervical spondylosis by the age of 70. This means that people with AS might also start to develop symptoms of spondylosis as they get older.
Last reviewed: May 2013