<prompt> Which of the following condition can be responsible for heterotopic calcification in a 40 year old lady?Gouty ahritisOsteo ahritisReactive ahritisAnkylosing spondylitis  <response>: Heterotopic calcification means pathological calcification. It may be dystrophic or metastatic calcification. Calcification of the anterior spinal ligament occurs in ankylosing spondylitis which gives it the flowing wax appearance. Ref: Robbins pathology, 6th Edition, Page 1252; Harrison 17th Edition, Page 2112 