Bladder with two diverticula
A bladder diverticulum is a pouch in the bladder wall that a person may either be born with ("congenital") or get later ("acquired").
A congenital bladder diverticulum forms when some of the bladder lining pokes through a weak part in the bladder wall. A congenital diverticulum is most often found when you are still a child, and there is often only one pouch. They often don't need to be treated.
Female urinary tract
Acquired bladder diverticula (more than one diverticulum) are most often caused by a block in the bladder outlet (such as from a swollen prostate or scars in the urethra), the bladder not working well because of nerve injury or, rarely, from prior bladder surgery. With acquired diverticula, many pouches often form. These are most often seen in older men, who tend to get bladder outlet blocks more often.
How Does the Bladder Usually Work?
Male urinary tract
The bladder is a balloon-shaped organ that stores urine, which is made in the kidneys. It is held in place by pelvic muscles in the lower part of your belly. When it isn't full, the bladder is relaxed. Nerve signals in your brain let you know that your bladder is getting full. Then you feel the need to pee. The brain tells the bladder muscles to squeeze (or "contract"). This forces the urine out of your body through your urethra.