These are diverticula, are pockets that stick off the colon to the outside. They are not to be confused with polyps which are solid structures that project to the inside or lumen of the colon.
Diverticulosis is an anatomical condition found frequently in the elderly.
The greatest risk is that of perforation of a diverticulum which may allow bacteria to cause an infection on the outside of the colon. This usually clears up with IV fluids and antibiotics but, rarely, surgery is required. This may mean resection of some large intestine or even a colostomy. Diverticulosis has been considered a degenerative disorder in the past. Many patients with diverticulosis have, unfortunately, been the recipients of bad advice regarding their diets.