<prompt> Bamboo spine appearance is seen in -Ankylosing spondylitisRheumatoid arthritisOsteoarthritisDISH  <response>: Ans. is a i.e., Ankylosing spondylitis Radiological features of ankylosing spondylitis Radiographic evidence of sacroiliac joint is the most consistent finding in ankylosing spondylitis and is crucial for diagnosis. The findings are -i Sclerosis of the articulating surfaces of SI jointsii Widening of the sacroiliac joint spaceiii Bony ankylosis of the sacroiliac jointsiv Calcification of the sacroiliac ligament and sacro-tuberous ligamentsv Evidence of enthesopathy - calcification at the attachment of the muscles, tendons and ligaments, particularly around the pelvis and around the heel. X-ray of lumbar spine may showi Squaring of vertebrae : The normal anterior concavity of the vertebral body is lost because of calcification of the anterior longitudinal ligament.ii Loss of the lumbar lordosis.iii Bridging osteophytes syndesmophytesiv Bamboo spine appearance 