The azygos venous system returns blood from the posterior walls
of the thorax and the abdomen and dumps directly into the superior
vena cava. The origin of this system begins at the various
capillaries, it is a large and very variable network of veins.
the azygos vein is situated on the rightside. embryologically
the azygos vein must commences from the postrior surface of the
inferior venacava at the level of renal veins. this azygos vein is
called lumbar azygos vein.
azygos vein may also commences by the fusion of the right
subcostal vein and right ascending lumbar vein.
development from the azygos line of veins of the right side and
right posterior cardinal vein.
this forms the azygos system of veins including others like,
hemiazygos vein, accessory hemiazygos vein.
