The large bowel lies more peripherally in the abdomen. It has haustra, or folds, which only partially extend into the lumen. Its width should not exceed 10cm. If the ileocaecal valve is competent, only the large bowel dilates and the caecum, which distends rapidly, is at risk of perforation. If the valve is incompetent the air passes backwards into the small bowel which will become dilated as well.
What can cause dilatation in the large bowel?
The causes are: