The azygos-hemiazygos system is a venous system in the thorax that drains the back, thoracoabdominal walls, and mediastinal organs.
Description
The azygos-hemiazygos system (from Greek, azygos meaning unpaired) is a venous network found in the posterior mediastinum on each side of the vertebral column.
- It begins in the thorax at the level of the 12th thoracic vertebra, as a collection of several veins, passing through the aortic opening under the right crus of the diaphragm.
- The azygos part of the system is located on the right side, while the hemiazygos system is located on the left
- In general, the azygos-hemiazygos system usually drains the following veins:
- Veins arising from the posterior aspect of the inferior vena cava
- Renal veins
- Posterior intercostal veins