AZYGOS VEINS

Question 1

The azygos vein is present only on

Answer 1

The right side in the upper part of posterior abdominal wall and posterior mediastinum

Question 2

Azygos vein connects

Answer 2

SVC And IVC

Question 3

Functions Of Azygos Vein

Answer 3

1. It drains venous blood from the thoracic wall and upper lumbar region.
2. It forms an important collateral channel connecting the superior vena cava and inferior vena cava.

Question 4

How is Azygos Vein Formed

Answer 4

It is formed in various ways:
1. Union of right subcostal and right ascending lumbar vein at T12 Level
2. Arises from the posterior aspect of the inferior vena cava (IVC) near the renal veins.
3. As a continuation of right subcostal vein.
4. Occasionally, it may arise from right renal or right first
lumbar vein.

Question 5

Course of Azygos Vein

Answer 5

After the formation of Azygos vein it ascends upwards and passes thru aortic opening in diaphragm and enters the posterior mediastinum where it ascends vertically upwards in front of vertebral column and at T4 Level arches forwards above the Hilum of Right lung to terminate at level of 2nd costal cartilage

Question 6

Relations of Azygos Vein

Answer 6

Anterior: Esophagus (right edge).

Posterior:

1. Lower 8th thoracic vertebrae.
2. Right posterior intercostal arteries.

To the right:

1. Right lung and pleura.
2. Greater splanchnic nerves.

To the left:

1. Thoracic duct.
2. Descending thoracic aorta.
3. Esophagus (right border).

Question 7

The tributaries of the azygos vein are

Answer 7

1. Lower 7th right posterior intercostal veins except first.
2. Right superior intercostal vein (formed by union of 2nd, 3rd, and 4th right posterior intercostal veins).
3. Hemiazygos vein (at the level of T7 or T8 vertebra).
4. Accessory hemiazygos vein (at the level of T8 or T9 vertebra).
5. Right subcostal vein.
6. Right bronchial vein.
7. Right ascending lumbar vein.
8. Esophageal veins with the exception of those at its lower end.
9. Mediastinal veins.
10. Pericardial veins.