Henry Gray (18251861). Anatomy of the Human Body. 1918.
renal veins join the cardinals, and at the same level a cross communication is established on either side between the cardinal and subcardinal (Fig. 478).
FIG. 479 Diagram showing development of main cross branches between jugulars and between cardinals. (See enlarged image)
FIG. 480 Diagram showing completion of development of the parietal veins. (See enlarged image)
The portion of the right subcardinal behind this cross communication disappears, while that in front, i.e., the prerenal part, forms a connection with the ductus venosus at the point of opening of the hepatic veins, and, rapidly enlarging, receives the blood from the postrenal part of the right cardinal through the cross communication referred to. In this manner a single trunk, the inferior vena cava(Fig. 480), is formed, and consists of the proximal part of the ductus venosus, the prerenal part