Frontal view of the abdomen with<unk> sign, patient was found to have duodenal atresia. In radiology, the<unk> sign is a feature of pediatric imaging seen on radiographs or prenatal ultrasound in which two air filled bubbles are seen in the abdomen, representing two discontiguous loops of bowel in a proximal, or 'high,' small bowel obstruction. The finding is typically pathologic, and implies either duodenal atresia, duodenal web, annular pancreas, and on occasion midgut volvulus, a distinction that requires close clinical correlation and, in most cases, surgical intervention. Distal gas is more often seen with midgut volvulus, duodenal stenosis and duodenal web, though this not always present. In such cases, distinguishing the diagnoses depends on clinical presentation.
Double bubble 
Companion shadow
Bio-secure bubble
Bird fancier's lung
No reflow phenomenon
Apex beat
Parasternal heave
Grand Rounds