Reading an Abdominal X-ray

Key points

• • Assess the bowel gas pattern: small bowel (central, valvulae conniventes) vs large bowel (peripheral, haustra).
• • Small-bowel dilatation over 3 cm, large bowel over 6 cm and caecum over 9 cm suggest obstruction.
• • Look for free air (perforation - better on an erect chest X-ray), calcification and foreign bodies.
• • The AXR is used mainly for obstruction, toxic megacolon and stones; CT is more sensitive.