&Ankylosing Spondylitis=AS is a chronic inflammatory arthritis of the back, involving the SI joints and articular joints of the spine. Additionally, AS may be associated with peripheral arthritis of the knees, hips, and shoulders as well as extraarticular manifestations involving the eyes, heart, and lungs.  The principal clinical manifestation of AS is enthesitis (which is pain and swelling at the insertion of the tendon on bone e.g. Achilles). The usual presenting symptom is inflammatory back pain that presents with more than one hour of morning stiffness, is insidious in onset, and usually persists for more than 3 months. It is worsened by rest and improved with exercise.  Sacroiliitis, causes pain in the buttocks. A minority of patients present with oligoarthritis or enthesitis that particularly affects the heel or hip.