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.
What are the hemiazygos veins?
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 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.
What does Azygos fissure mean?
azygos fissure is a developmental abnormality caused by the right posterior cardinal vein (one of the precursors of the azygos vein) failing to migrate over the right lung apex, and instead penetrating and grooving it.
Where does the hemiazygos vein drain?
superior vena cava
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].
Where is the azygos and hemiazygos veins located?
The azygos venous system is located on either side of the vertebral column and drains the viscera within the mediastinum, as well as the back and thoracoabdominal walls. This system consists of the azygos vein and its two main tributaries: the hemiazygos vein and the accessory hemiazygos vein.
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.
Where do hemiazygos veins drain?
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 causes Azygos fissure?
An azygos lobe is a normal variant that develops when a laterally displaced azygos vein creates a deep pleural fissure into the apical segment of the right upper lobe during embryological development.
