Mesentery, omentum, peritoneum: Embryology, normal anatomy and anatomic variants

Abstract

The abdominal cavity is divided into the peritoneal and extraperitoneal compartments, separated by the posterior parietal peritoneum. It extends from the diaphragm to the pelvic floor. The visceral peritoneum covers the intraperitoneal and part of the pelvic organs. The parietal and visceral layers of the peritoneum are in contact; the potential space between them is called the peritoneal cavity and is a part of the embryologic abdominal cavity or primitive coelomic duct. This abdominal cavity is a very complex structure and spreading of different diseases is dependent not only on the force of the gravity and negative pressure, but also on the numerous peritoneal recesses and folds. A total of 11 large ligaments and mesenteries comprise the complex structures within the abdominal cavity, the peritoneal recesses and folds, or compartments. After the completion of embryologic development of organs within the peritoneal cavity, they come to lie either intra- or extraperitoneally. The organs that remain intraperitoneal retain a so-called free mesentery.