accessory hemiazygous vein
The accessory hemiazygous vein is highlighted in a diagram of the thoracic venous system.
Noun: 1. A specific vein in the thoracic region: The accessory hemiazygos vein is a blood vessel that drains blood from the upper posterior part of the chest wall. It is formed by the joining of several posterior intercostal veins (typically from the fourth to the seventh spaces) and ultimately connects to the azygos vein.
The term is used exclusively in anatomical, medical, and biological contexts to describe this specific vascular structure. * The accessory hemiazygos vein is a key component of the venous drainage system of the thorax. * During the dissection, the surgeon carefully identified the accessory hemiazygos vein to avoid accidental injury.
- The accessory hemiazygos vein is part of the azygos system, which provides an important collateral pathway for venous blood to return to the heart if the main vessel (the superior vena cava) is blocked.
- Azygos vein (n.): The primary vein in the azygos system, which receives blood from the accessory hemiazygos vein and the hemiazygos vein before emptying into the superior vena cava.
- Hemiazygos vein (n.): A vein similar to the accessory hemiazygos vein but typically draining the lower posterior intercostal spaces (eighth to eleventh) on the left side.
- Posterior intercostal veins (n.): The veins that drain the intercostal spaces and unite to form the accessory hemiazygos, hemiazygos, and azygos veins.
- Accessory hemiazygos (n.): A common abbreviated form used in medical terminology.
- Superior hemiazygos vein (n.): An alternative name sometimes used, emphasizing its position relative to the hemiazygos vein.
This term has only one specific anatomical meaning. It is not used in general or figurative language.
The accessory hemiazygous vein is highlighted in a diagram of the thoracic venous system.
- a vein formed by the union of the 4th to 7th posterior intercostal veins; empties into the azygos vein