This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Orthopaedics
[{'content': 'Last joint to be involved in ankylosing spondylitis \nSelect and explain. \nA. Sacroiliac joint, B. Temporo mandibular joint, C. Costoveebral joint, D. Veebral aicular facet joint', 'role': 'user'}, {'content': "Answer: B \nExplanation: 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 appearance(Refer: Apley's System of Ohopedics and Fracture, 9th edition, pg no: 58-61)", 'role': 'assistant'}]