aortic foramen
aortic hiatus

The area behind this arch is known as the aortic hiatus.

The aortic hiatus is a hole in the human diaphragm.

This fibrous arch forms the anterior aspect of the aortic hiatus, through which the aorta, thoracic duct, and azygos vein pass.

The crura connect to form an arch, behind which is the aortic hiatus, through which pass the aorta, the azygos vein, and the thoracic duct.

It begins at the level of the diaphragm, crossing it via the aortic hiatus, technically behind the diaphragm, at the vertebral level of T12.

It is placed superior, anterior, and slightly left of the aortic hiatus, and transmits the esophagus, the vagus nerve, the left inferior phrenic vessels, and some small esophageal arteries from left gastric vessels.

Structures passing through the inferior thoracic aperture between the thorax and abdomen include the inferior vena cava and esophagus, both of which pass through the diaphragm, and the abdominal aorta and thoracic duct which pass posterior to the diaphragm through the aortic hiatus.

It begins at the lower border of the fourth thoracic vertebra where it is continuous with the aortic arch, and ends in front of the lower border of the twelfth thoracic vertebra, at the aortic hiatus in the diaphragm where it becomes the abdominal aorta.