Dr. Rollin Daniel: The subject of the clinic today is diaphragmatic hernia.
The development of the diaphragm is complicated, and as a result of irregularities in its development, herniation of abdominal organs may occasionally occur into the thoracic cavities. The diaphragm is a strong muscle in the normal person. It has a central tendon into which muscle fibers which radiate toward this tendon insert. It is perforated normally by three foramens, through which the aorta, the esophagus and the vena cava extend.
The aorta is retroperitoneal, and there is never, so far as I know, protrusion of viscera through that opening. The vena cava is surrounded by strong muscles and tendons, and if herniation occurs through that foramen, it certainly does so extremely rarely.
The esophagus, on the other hand, is surrounded by circular muscle and connective tissue which varies in thickness and in strength, and the esophageal foramen varies
DIAPHRAGMATIC HERNIA. Arch Surg. 1950;60(3):618-632. doi:10.1001/archsurg.1950.01250010637015