Ankylosing spondylitis (AS) is a common inflammatory rheumatic disease with a prevalence of 0.5-1.0%. Men are more commonly affected by the disease as compared to women, ratio 2.6-4:1. Pain in the back is a frequent symptom of debut. This pain is often associated with sacroilitis. In later stages also the lumbar, thoracic and cervical spine are hit by the disease. Peripheral joints, eyes, heart, lungs and urinary tract may also be influenced.