Ankylosing spondylitis (AS) is the commonest expression of SpA. It is 2-3 times more common in men than women. IBP in a young patient is the most frequent symptom, but peripheral arthritis and/or enthesopathy may be found in some patients. Uveitis, positive family history for AS, impaired spinal mobility or chest expansion, all supports the diagnosis of AS [1].Axial involvement is one of the disease characteristics and 90% of patients have radiographic sacroiliitis during the course of the disease. Currently, a patient can be classified as having definite AS, if at least one clinical criterion (IBP, limitation of lumbar spine or limitation of chest expansion) plus a radiologic criterion (bilaterally grade 2 or unilateral grade 3-4 sacroiliitis) are fulfilled [9].