small pouch in the colon. These pouches are not painful or harmful unless they become infected or irritated.
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Biology Dictionary
Definition:
A small sac-like structure that sometimes forms in the walls of the intestines; diverticula can trap particles of food (especially small seeds and undigested grains) and become very inflammed and painful (this condition is called diverticulitis).
A diverticulum is a pouch or a sac formed at weak points in the muscular coat of the digestive tract (especially the small intestine). Inflammation of the diverticula is called diverticulitis.