Caudally, they join the corresponding subcardinal vein close to the inter-cardinal anastomosis thus the azygos vein
originates as the ascending lumbar vein on both sides.
The lymphadenpathy was more subtle than the sarcoid case above, but can be confidently called because of the adjacent azygos vein
and aortic enhancement.
Inadvertent port: Catheter placement in azygos vein
. Int J Angiol 2012;21:103-6.
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).
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.
Dilated collateral paravertebral veins were draining into the dilated azygos vein
that joins the SVC at the normal location.