Pressure conditions which exist within the peritoneal cavity have received much less attention than that given to considerations of the pressure within other body cavities. Since one understands pressure to be the action of a force against an opposing force, it is possible to think of a pressure within the cleft between the parietal and the opposing visceral peritoneum.
Under normal conditions the peritoneal cavity, as it is known anatomically, is not a cavity but a cleft. However, in this discussion the term peritoneal cavity will, because of its wider usage, be used to denote the potential peritoneal space, or, more strictly speaking, the peritoneal cleft. The ramifications of this cleft extend, for the most part, throughout the abdominal cavity and between the various organs. Nothing is contained within this space except a small amount of peritoneal fluid which moistens its surfaces. There is no communication with the outside except