What is the function of the hemiazygos and accessory hemiazygos veins?
What is the function of the hemiazygos and accessory hemiazygos veins?
The accessory hemiazygos vein drains the superior left hemithorax. It arises from the 4th to 8th left posterior intercostal veins and lies longitudinally on the left side of the vertebral bodies. It also drains the left bronchial vein and some veins from the oesophagus.
What drains into the hemiazygos vein?
The azygos vein arises from the right ascending lumbar vein. It drains blood from the right posterior intercostal veins. It travels close to the right side of the inferior 8 thoracic vertebrae. It arches anteriorly just above the hilum of the right lung and drains into the superior vena cava.
What is accessory hemiazygos vein?
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.
Where does accessory hemiazygos drain into?
brachiocephalic vein
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].
How is accessory hemiazygos vein formed?
The accessory hemiazygos vein is formed by the confluence of the middle left posterior intercostal veins. It descends to the left of midline, adjacent to the thoracic vertebrae and crosses posteriorly to the aorta at the level of T7-8 to drain into the azygos vein.
Why is it called Hemiazygos?
The name for this vein is derived from that of the azygos vein. Azygos means ‘unpaired’, and hemi means half. This vein mirrors the bottom half of the azygos vein.
Where does the left superior intercostal vein drain into?
left brachiocephalic vein
The left superior intercostal vein forms by the union of the 2nd to 4th left posterior intercostal veins. It courses superiorly to the left of the midline, arches posteriorly lateral to the aortic arch to drain into the left brachiocephalic vein. It typically communicates with the accessory hemiazygos vein.
Is azygos vein normal?
IVC interruption with azygos or hemiazygos vein continuation is considered to be a rare congenital anomaly. The estimated prevalence is 0.6% to 2% in the presence of congenital heart disease (CHD) and less than 0.3% in otherwise normal fetuses.
Why is it called hemiazygos?
What is the vertebra level of termination of accessory hemiazygos vein into the azygos vein?
T7 vertebra
The accessory hemiazygos vein usually crosses the midline and terminates by draining into the azygos vein at the level of the T7 vertebra.
Where do anterior intercostal veins drain into?
The anterior intercostal veins originate from the intercostal space just inferior to anterior aspects of their respective ribs and drain into the internal thoracic and musculophrenic veins.
Where do intercostal veins drain?
The intercostal veins are a group of veins which drain the area between the ribs (“costae”), called the intercostal space. Posterior intercost veins that drain into the Superior intercostal vein – 2nd, 3rd, and 4th intercostal spaces. The superior intercostal vein then drains into the Azygous vein.