Fig. 3From: Upper gastrointestinal series in children: what surgeons need to knowTwo different patients with pyloric obstruction. Upper row neonate with infantile hypertrophic pyloric stenosis. a Plain AP view shows stomach with wave-like contour (caterpillar sign) and paucity of distal abdominal gas. b AP view shows distended stomach with delayed gastric emptying. c Ultrasound scan showing elongated and thickened pyloric canal. d, e Patient with idiopathic acquired gastric outlet obstruction. d AP view shows dilated stomach displacing the surrounding bowel loops. e Oblique view shows the dilated stomach with delayed gastric emptyingBack to article page