What is a hemiazygos vein?

What is a hemiazygos vein?

The hemiazygos vein arises from the left ascending lumbar vein. It drains the lower left posterior intercostal veins and ascends on the vertebral bodies posterolateral to the descending aorta. At T8, it crosses to the right behind the aorta, thoracic duct, and esophagus, and joins the azygos vein.

What is the difference between Azygos and hemiazygos veins?

Thus, azygos means unpaired. The azygos vein is unpaired in that there is only one in the body, mostly on the right side. 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.

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.

Where is the hemiazygos?

The hemiazygos vein runs in the posterior mediastinum and drains into the azygos vein at the level of the eighth thoracic vertebra. Along its course, the hemiazygos vein receives several tributaries which include: ninth, tenth and eleventh left posterior intercostal veins, mediastinal and esophageal veins.

How does the Hemiazygos vein enter the thorax?

Azygos vein It enters the thorax via the aortic hiatus in the diaphragm and ascends posteriorly alongside the vertebral bodies, arching over the right main bronchus at T5-T6 and enters the superior vena cava (SVC) at T4 2.

What does the hemiazygos vein drain into?

The azygos vein drains into the superior vena cava. At approximately T8–T9 the hemiazygos veins join the azygos vein usually posterior to the aorta. The accessory hemiazygos joins the azygos at T7–T8 crossing posterior to the aorta [1].

What side of the body is the hemiazygos vein?

left
Anatomical terminology The accessory hemiazygos vein, also called the superior hemiazygous vein is a vein on the left side of the vertebral column that generally drains the fourth through eighth intercostal spaces on the left side of the body.

What does the accessory hemiazygos vein drain into?

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].

What is the hemhemiazygos vein?

hemiazygos vein. A vein running along the back wall of the lower thorax on the left side of the thoracic aorta.

What does hemiazygos mean in medical terms?

medical Definition of hemiazygos vein. : a vein that receives blood from the lower half of the left thoracic wall and the left abdominal wall, ascends along the left side of the spinal column, and empties into the azygos vein near the middle of the thorax.

What is the left equivalent of the azygos vein?

Hemiazygos vein (Vena hemiazygos) The hemiazygos vein (also known as the inferior hemiazygos vein) arises from the confluence of left lumbar ascending and subcostal veins. It is considered to be a left equivalent of the azygos vein.

What are the tributaries of the hemiazygos?

Along the way, the hemiazygos vein receives several tributaries including: Inferior three left posterior intercostal veins, which help to drain the muscles and skin of the posterior trunk, as well as the vertebral column. Mediastinal veins, which help to empty the mediastinum.