The space enclosed by the peritoneum. It is divided into two portions, the greater sac and the lesser sac or omental bursa, which lies behind the stomach. The two sacs are connected by the foramen of Winslow, or epiploic foramen.
the lower abdomen (belly) which contains the reproductive tract, bladder,kidneys and adrenals, small and large intestine, liver, pancreas and stomach. Endometriosis can be scattered all over the Peritoneal cavity