<prompt> Double bubble appearance in plain X-ray is seen in :Annular pancreasLobular pancreasCa pancreasPancreatitis  <response>: Ans: a Annular pancreas Ref: Bailey and Love, 24th ed, p. 1120Annular pancreas is due to failure of rotation of ventral pancreatic bud. On abdominal radiograph it shows double -bubblesign, due to interrupted gastro duodenal shadow produced by rigid ring of pancreatic tissue.Double bubble sign is also seen in: Duodenal atresia Duodenal stenosisRemember Single bubble sign- in pyloric stenosisDouble bubble sign- duodenal atresia, Ladds bandmalrotation, annular pancreasTriple bubble sign- is seen in jejunal atresiaGasless abdomen on X-ray Acute pancreatitis Annular pancreas Bowel malrotation Congenital hypertrophic pyloric stenosis Congenital diaphragmatic hernia Duodenal atresia Mesenteric infarctionOther important signs String of beads appearance-intestinal obstruction Coffee bean sign-closed loop obstruction Bird of prey sign in Barium enema-sigmoid volvulus Chain of lakes in ERCP-chronic pancreatitis Crow foot, Mercedes Benz sign-gall stones. 