Diverticulosis in an unused colon.

It has been suggested that diverticulosis is the result of uncoordinated muscle activity of the colon in response to normal physiologic stimuli such as eating, emotions and the urge to defecate. This results in spasm of the longitudinal muscle with the heaping up of circular muscle bundles, creating interhaustral folds along the colonic wall adjacent to the mesentery. Narrowing of the lumen and shortening of the colon results which is enhanced by a low residue diet and prevented by a bulky diet. Segmentation results when muscular contraction approximates these interhaustral folds. Higher intraluminal pressure is produced in the areas of segmentation which enhances the development of diverticulosis in the bowel between interhaustral folds where there is a thinning of the circular muscles and where vessels pierce the colonic wall. The case presented herein supports these hypothesis in that the patient has experienced the extreme in a low residue diet for 50 years.