Cavitas peritonealis

The peritoneal cavity is a potential space between the parietal peritoneum (the peritoneum that surrounds the abdominal wall) and visceral peritoneum (the peritoneum that surrounds the internal organs).

The parietal and visceral peritonea are layers of the peritoneum named depending on their function/location.

It is one of the spaces derived from the coelomic cavity of the embryo, the others being the pleural cavities around the lungs and the pericardial cavity around the heart. It is the largest serosal sac, and the largest fluid-filled cavity, in the body and secretes approximately 50 ml of fluid per day.

This fluid acts as a lubricant and has anti-inflammatory properties. The pericardial cavity is divided into two compartments – one above, and one below the transverse colon.