Many people have small pouches in their colons that bulge outward through weak spots, like an inner tube that pokes through weak places in a tire. Each pouch is called diverticulum. Pouches (more than one) are called diverticula. The condition of having diverticula is called diverticulosis. About 10 percent of Americans over the age of 40 have diverticulosis.
When the pouches become infected or inflamed, the condition is called diverticulitis.