A diverticulum (plural: diverticula) is medical or biological term for an outpouching of a hollow (or a fluid filled) structure in the body.
In medicine the term usually implies that the structure is not normally present, i.e. pathological. However, embryologically, some normal structures begin development as a diverticulum arising from another structure.
An alphabetical listing of some frequently encountered diverticula follows:
Pathological
Bladder diverticulum: Balloon-like growths on the bladder commonly associated with a chronic outflow obstruction, such as benign prostatic hypertrophy in older males. Usually found in pairs on opposite sides of the bladder, bladder diverticula are often surgically removed to prevent infection, rupture, or even cancer.
Cardiac diverticulum: A very rare congenital malformation of the heart that is usually benign [1]
Colonic diverticula: These can become infected (see diverticulitis) and can perforate, requiring surgery
Large bowel (sigmoid colon) showing multiple diverticula. Note how the diverticula appear on either side of the longitudinal muscle bundle (taenium).
Diverticulum of Kummerall: unusual nomenclature, in that focal dilatations of a blood vessel are properly referred to as aneurysms
Duodenal & Jejunal diverticul(um|a): congenital lesions, may be a source of bacterial overgrowth, may perforate and may result in abscesses
Epiphrenic diverticulum: due to dysfunction of the lower esophageal sphincter, as in achalasia