Diverticular Disease
A structural consequence of high intraluminal pressure forcing mucosa out through weak points in the colonic wall, so a low-fibre Western diet, the sigmoid colon's narrow calibre, and the complications of diverticulitis all follow from one mechanical principle.
First principles
Diverticula form where high pressure meets a structurally weak wall
A low-fibre diet produces small-volume, low-bulk stool, which the colon must squeeze harder to propel: segmental contraction generates exaggerated intraluminal pressure, most so in the sigmoid colon, which has the narrowest lumen and highest resting pressure of the whole large bowel. The colonic wall is structurally weakest where the vasa recta perforate the muscularis to supply the mucosa. Sustained high pressure pushes mucosa and submucosa out through these points, herniating outward as pseudodiverticula (lacking a muscular coat). This is why diverticulosis is overwhelmingly a disease of the sigmoid colon and of populations eating a low-fibre diet.
Educational content pending clinical review. Not medical advice.