<prompt> Bone within a Bone appearance is seen in:Osteo-necrosisOsteoporosisOsteopetrosisOsteomyelitis  <response>: Ans. c OsteopetrosisRef: Harrison 19th ed. 426e-4 Bone within a bone describes the bones that appear to have another bone within them.Causes: P.O.S.T-C.G.D Pagets disease of bone Osteopetrosis Sickle cell disease Thalassemia Caffeys disease Gauchers disease Growth recovery lines after infancy Hypervitaminosis D 