On a plain abdominal radiograph, a dilated bowel loop shows fine lines crossing the entire width of the lumen at close regular intervals. This feature distinguishes it from another dilated segment whose wall markings are widely spaced, incomplete, and do not traverse the full lumen. The two findings respectively represent:

• A Haustrations in small bowel and valvulae conniventes in colon
• B Valvulae conniventes in small bowel and haustrations in colon ✓
• C Santorini's folds in small bowel and mucosal oedema in colon
• D Plicae circulares in stomach and taeniae coli in colon

Explanation

Valvulae conniventes (plicae circulares) are closely spaced mucosal folds that cross the entire lumen width, characteristic of small bowel, giving the stacked coin appearance. Haustrations are wider spaced, incomplete folds that do not span the full diameter, characteristic of large bowel. Distinguishing these patterns on plain films is essential to identify whether dilated loops are small or large bowel when assessing obstruction.

Reference: Bailey and Love's Short Practice of Surgery, 28th ed.

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Written and medically reviewed by the StethoPrep medical team.