Abstract
As we advance our knowledge in understanding abdominal compartment syndrome, it is worth going back to revisit our basic embryologic development of the main determinant of the abdominal and thoracic cavities, i.e., the diaphragm. The abdominal and thoracic cavities used to be one cavity at some stage of the embryonic life — “intraembryonic coelom” — before the “septum transversum” — diaphragmatic origin — divided it into two cavities. Therefore, if a condition develops that will impair the diaphragm from separating the cavities, leading to the possibility of pressures to transmit from one cavity to another, this becomes relevant as abdominal compartment syndrome. Diaphragmatic eventration is a congenital developmental defect in the muscular portion of the diaphragm with preserved attachments to the sternum, ribs, and dorsolumbar spine, leading to a semi-membranous diaphragm that anatomically separates the two cavities, but not physiologically. In the case of high abdominal pressure, the pressure will transmit to the thoracic cavity, causing derangement in both the anatomy and physiology. This was reported and named “Thoracoabdominal Compartment Syndrome”.