azygos vein

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azygos vein

[ā′zī·gəs ‚vān]
(anatomy)
A branch of the right precava which drains the intercostal muscles and empties into the superior vena cava.
References in periodicals archive ?
sup][9] For example, the azygos vein would act as the bypass collateral to the right atrium during the insertion under the condition that SVC obstruction lies below the azygos vein.
Azygos vein is formed by the union of the ascending lumbar veins with the right subcostal veins at the level of the 12th thoracic vertebra, ascending in the posterior mediastinum, and arching over the right main bronchus at the root of the right lung to join the superior venacave.
Caption: Figure 1: Enhanced axial chest CT image (a) and oblique axial thin-slab maximum-intensity-projection (MIP) images (b, c) inferior to (a) show thrombosed and stenosed SVC (arrowhead) and distended and occluded azygos vein (black block arrow).
It contains the heart enclosed in the pericardium, the ascending aorta, the lower half of the superior vena cava with the azygos vein opening into it, the bifurcation of the trachea and the two bronchi, the pulmonary artery dividing into its two branches, the right and left pulmonary veins, the phrenic nerves, and some bronchial lymph glands.
Contrast abdominopelvic CT showed an old complete thrombosis of the left common iliac vein, recent complete thromboses of the left venous junctions (external and internal iliac veins, common femoral deep and superficial veins, ascending lumbar vein and various presacral collaterals), dilated azygos vein, partial eccentric thrombosis of the IVC, approximately 18 mm lower than the flow level of the right renal vein, with a 5mm clot on a length of 27mm, with a reduced caliber on almost its entire length from the origin to the level of the caudate lobe.