What are azygos and hemiazygos veins?

What are azygos and hemiazygos veins?

The azygos vein transports deoxygenated blood from the posterior walls of the thorax and abdomen into the superior vena cava vein. A major tributary is the hemiazygos vein, a similar structure on the opposite side of the vertebral column.

Where does the hemiazygos vein join the azygos vein?

The hemiazygos vein ascends the thorax to the left of the vertebral bodies and passes behind the esophagus at the level of T9 to join the azygos vein.

What is the function of the hemiazygos and accessory Hemiazygos veins?

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.

Does the hemiazygos vein drain into the azygos vein?

The hemiazygos vein runs in the posterior mediastinum and drains into the azygos vein at the level of the eighth thoracic vertebra.

Do azygos veins have valves?

The azygos vein contains a valve halfway along the azygos arch (between the vertical azygos vein and the point where the azygos vein enters the SVC). This valve is a common place for the intravenously injected contrast agent to accumulate, which may simulate pathology on CT 3.

Where does the azygos vein empty?

The azygos vein originates at the junction of the right ascending lumbar and subcostal veins, entering the chest through the aortic hiatus. It ascends along the anterolateral surface of the thoracic vertebrae and arches ventrally to the right main bronchus at T5–T6, draining into the SVC.

What is between the esophagus and azygos vein?

The hemiazygos vein, which as a normal anatomical variation sometimes directly joins the sub- clavian vein, is also considered to be one of the pathways between the esophagus and the subclavian vein (16). These vessels were considered to constitute the pathways of drainage into the brachiocephalic venous sys tem .

What is the function of the hemiazygos vein?

The hemiazygos vein helps to drain the left mediastinum and left lower esophagus. The hemiazygos vein crosses from left to right at approximately the level of T9 and terminates by emptying into the azygos vein. The accessory hemiazygos vein connects the middle three or four intercostal veins.

Where does the accessory hemiazygos vein empty?

The accessory hemiazygos vein, also called the superior hemiazygos vein, drains the superior left hemithorax. In a majority of cases there is a small connection to the left superior intercostal vein, and rarely, 1–2% of the time, the accessory hemiazygos vein drains into the brachiocephalic vein [3].

Where are the azygos vein and the hemiazygos vein located?

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.

Where are the veins located on the left side of the body?

The vein is so named because it has no symmetrically equivalent vein on the left side of the body. The azygos system is considered to be the azygos vein located from rib number 2 to rib number 4 while the left part of the body has the hemiazygos vein and the accessory hemiazygos vein as the venous system.

Where does blood go after retrogression of the left common cardinal vein?

Following retrogression of the left common cardinal vein, the left azygos vein loses contact with the posterior cardinal vein. Thus, the blood drains into the right azygos line. 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.

Are there any animals that have paired azygos veins?

This terminology is only accurate in some species, such as the human, dog, and cat. Ruminants (such as sheep and cows) have paired azygos veins. Diagram showing completion of development of the parietal veins. The venæ cavæ and azygos veins, with their tributaries. Mediastinal surface of right lung.