GI Radiology > Small Bowel > Disease Patterns > Small Bowel Obstruction

Structural Abnormalities

Small Bowel Obstruction

Radiographic - Plain Film

  • Supine
    • Distended loops of bowel
    • Valvulae conniventes are present
    • "Stepladder" pattern
    • Variable amount of gas in colon depending on severity and duration of obstruction
    • Gasless abdomen will be seen if distended loops are fluid-filled
  • Erect / Lateral Decubitus Plain Film
    • "String of pearls" sign from small collections of air
    • Air-fluid levels
    • Differential levels - air-fluid levels are at different heights
    • Closed-loop obstruction - entrapment of a loop of bowel by obstruction (can occur with adhesions, hernias, volvulus)

Supine abdominal plain film demonstrates dilated loops of small bowel from an inguinal hernia.