Small bowel obstruction due to hernia

Small bowel obstruction. This CT shows moderately dilated small bowel in the left side of the abdomen (you can see the valvulae conniventes). The cause was the small paraumbilical hernia in the midline (arrow). CT is an excellent tool for the evaluation of small bowel obstruction; not only will it tell us the location of the obstruction (known as the ‘zone of transition’), in some cases we can see the actual cause, as in this example. However, you should note that adhesions are not visible on CT; when we don’t see another reason for obstruction, in a patient who we know has had previous abdominal surgery, we usually suggest that adhesions are the cause.