hemiazygos vein

The structure of the hemiazygos vein is often variable.

It may also communicate with the accessory hemiazygos vein.

A major tributary is the hemiazygos vein, a similar structure on the opposite side of the vertebral column.

Specifically, the hemiazygos vein mirrors the bottom part of the azygos vein.

The hemiazygos may or may not be continuous superiorly with the accessory hemiazygos vein.

The accessory hemiazygos vein varies inversely in size with the left superior intercostal vein.

It also drains, although with less significance, to the hemiazygos vein, posterior intercostal vein and bronchial veins.

The remaining posterior intercostal veins drain into the azygos vein on the right, or the hemiazygos vein on the left.

The hemiazygos vein (vena azygos minor inferior) is a vein running superiorly in the lower thoracic region, just to the left side of the vertebral column.

The supracardinal veins form part of the inferior vena cava, the intercostal veins, hemiazygos vein and azygos vein.

While there is the hemiazygos vein and its accessory on the left side of the body, they are considered tributaries of the azygos vein rather than its left-side equivalent.

The hemiazygos vein and the accessory hemiazygos vein, when taken together, essentially serve as the left-sided equivalent of the azygos vein.

The azygos system of veins is considered to be the azygos vein, along with its left-sided counterparts, the hemiazygos vein and the accessory hemiazygos vein.

The accessory hemiazygos vein is a vein on the left side of the vertebral column that generally drains the fifth through eighth intercostal spaces on the left side of the body.

The contents of posterior mediastinum can be remembered using the mnemonic, "DATES", for Descending aorta, Azygous vein and hemiazygos vein, Thoracic duct, Esophagus, Sympathetic trunk/ganglia.

It receives the posterior intercostal veins from the 4th, 5th, 6th, and 7th intercostal spaces between the left superior intercostal vein and highest tributary of the hemiazygos vein; the left bronchial vein sometimes opens into it.

More rarely, vascular abnormalities are found, including interrupted inferior vena cava, bilateral superior or inferior venae cavae, intrahepatic interruption of the inferior vena cava with connection to the azygos or hemiazygos veins, and aberrant portal veins.

The left aortic intercostals run backward on the sides of the vertebrae and are covered by the left lung and pleura; the upper two vessels are crossed by the left superior intercostal vein, the lower vessels by the hemiazygos vein.

That is, the azygos vein serves to drain most of the posterior intercostal veins on the right side of the body, and the hemiazygos vein and the accessory hemiazygos vein drain most of the posterior intercostal veins on the left side of the body.