Double bubble appearance in plain X-ray is seen in :

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 -bubble"sign, 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, Ladd's band/malrotation, 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.