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Hemiazygos vein



Vein: Hemiazygos vein
Diagram showing completion of development of the parietal veins. (Hemiazygos vein visible at center-left.)
The venæ cavæ and azygos veins, with their tributaries.
Latin vena hemiazygos
Gray's subject #172 667
Drains to azygos vein
Dorlands/Elsevier v_05/12850474

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.

Additional recommended knowledge

Structure

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

The structure of the hemiazygos vein is often variable. It usually begins in the left ascending lumbar vein or renal vein, and passes upward through the left crus of the diaphragm to enter the thorax. It continues ascending on the left side of the vertebral column, and around the level of the ninth thoracic vertebra, it passes rightward across the column, behind the aorta, esophagus, and thoracic duct, to end in the azygos vein.

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

It receives the 9th, 10th, and 11th posterior intercostal veins and the subcostal vein of the left side, and some esophageal and mediastinal veins.

Etymology

The name for this vein is derived from that of the azygos vein. Azygos means 'unpaired', and hemi means half. This vein mirrors the bottom half the azygos vein.

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Hemiazygos_vein". A list of authors is available in Wikipedia.
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