The subcardinal vein
provides the suprarenal segment.
The paired subcardinal veins
are the next to appear with the right subcardinal vein
forming the suprarenal segment of IVC and the left subcardinal system regressing.
Under normal circumstances, the prerenal division of the IVC is formed following the union of the hepatic segment, which itself is a vitelline vein derivative, with the right subcardinal vein
The one described by Shulman in 1997, which states the persistence of the subcardinal vein
as IVC, seems to be the most accepted one .
The right subcardinal vein
develops into the suprarenal segment by subcardinal-hepatic anastomoses.
The supra-renal segment develops from the right subcardinal vein
and the infra-renal segment develops from the right supracardinal vein.
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.
Right subcardinal vein
(Prerenal segment) receives right suprarenal vein.
In particular, the postcardinal veins appear and remain in the pelvis as the common iliac veins, the right supracardinal vein persists to form the infrarenal IVC, and the right subcardinal vein
persists to develop into the suprarenal segment by formation of the subcardinal-hepatic anastomosis while the left subcardinal vein
and the left supracardinal vein regress completely [2, 4, 6].
Azygos venous system embryologically derived from subcardinal veins
. The right subcardinal vein
forms azygos vein and the left subcardinal vein
forms hemiazygos vein.
The authors suggest the explanation for this varying pattern based on this step of the embryological development of the right renal vein: There was an error on the fusion of the branches to the dorsal mesonephros derived from the right postcardinal vein, the dorsal-medial branches of the right supracardinal vein and the ventral branches of the right subcardinal vein
(the latter represented by the IRRV, marked by the presence of its gonadal tributary (Gillot).
a) the mesonephric vein draining into the left subcardinal vein
, b) part of the left subcardinal vein
c) communicating channels between the subcardinal veins