Abdominal x-ray review: bowel

Abdominal x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using ABDO X is a helpful and systematic method for abdominal x-ray review, where B refers to the assessment of the bowel loops.

Summary

• introduction
  • stomach, small bowel and large bowel may be differentiated on an abdominal x-ray
  • pathological features to detect include bowel dilatation, bowel loop displacement and bowel wall thickening
• procedure
  • the stomach usually appears thick-walled and lies in the left upper quadrant, and may contain the tip of a nasogastric tube
  • can you identify the small and large bowel? Use these features:
    • the small bowel usually lies centrally, has folds than run all the way across the diameter of the lumen (valvulae conniventes) and usually contains a small volume of air
    • the large bowel lies peripherally, has folds that run part of the way across the diameter of the lumen (haustral folds) and usually contains some air and fecal matter
  • is the bowel dilated? 
    • the 3-6-9 rule refers to the approximate allowable diameter (in centimeters) of the small bowel, large bowel and cecum
  • are the bowel loops are clustered centrally with hazy homogeneous opacification of the rest of the abdomen?
    • this is an indication that there may be ascites
  • is the wall of the large bowel thickened and undulating in its contour?
    • this is known as thumbprinting and indicates colonic wall edema which may be due to infection, inflammation or ischemia