<prompt> Last joint to be involved in ankylosing spondylitisSacroiliac jointTemporo mandibular jointCostoveebral jointVeebral aicular facet joint  <response>: Ankylosing spondylitisTypically a young man who presents with lower back pain and stiffness.HLA 27 association Clinical features Stiffness is usually worse in the morning and improves with activityEnthesopathy is characteristicApical fibrosisAnterior uveitisAoic regurgitation Achilles tendinitisAV node blockAmyloidosisCauda equina syndromeX-rays features - Sacroiliitis, Subchondral erosions, Sclerosis, Squaring of lumbar veebrae, Bamboo spine appearanceRefer: Apleys System of Ohopedics and Fracture, 9th edition, pg no: 58-61 