Ankylosing spondylitis. Coloured X-ray of a side- view of the cervical (neck) spine of a patient with ankylosing spondylitis. The base of the skull is at upper right. The spaces between the upper vertebrae (brown blocks) have shortened. This disease is a form of inflammatory arthritis that mainly affects the spine and is most common in men. The joints between the vertebrae become inflamed and then during the healing process extra bone forms between the vertebrae, eventually fusing them. This causes chronic neck pain and immobility. Treatment is with anti-inflammatory drugs, physical therapy, and in extreme cases, surgery.