Healthy small intestine, coloured contrast barium enema X-ray. This X-ray of the abdomen shows a healthy coiled small intestine (centre and upper centre), part of the colon (to its immediate left) and the surrounding pelvic bone. The small intestine breaks down and absorbs partially-digested food from the stomach, before passing it on to the large intestine (colon), where excess water is absorbed. The banding within the small intestine is caused by circular folds, called plicae circulares,in its mucosal lining. The folds increase the surface area through which nutrients can be absorbed. The radio-opaque barium, introduced through an enema, enables the shape of the soft tissues of the small intestine to be seen.