280 



THE DEVELOPMENT OF THE VASCULAR SYSTEM 



The Posterior Cardinal Veins and the Origin of the Inferior Vena Cava. 



The posterior cardinal veins course cephalad along the dorsal side of the mesone- 

 phroi and open into the common cardinal veins (Fig. 274, A). Each receives an 



R.Ar/t. cardinal vein 



R.Posi. cardinal vein. 

 Ream-Cardinal 



ubclar/'an Vein 

 R.vitelline ve, 

 ft. Umb'fcat 



fl.fbst.f ordinal 

 vein 



Exl.juqular Vein 

 Subclavian vein 



fat. 

 Card. Ve, 



Ischiadic vein 



Caudal vein 





Int. iliac veins 



Median sacra/ vein , 



FIG. 274. Four diagrams showing the development of the superior and inferior venae cavae and the 

 fate of the cardinal veins (modified after Kollmann). X in A, anastomosis between hepatic and sub- 

 cardinal vein; *, anastomosis between subcardinal veins; X in C, anastomosis between anterior car- 

 dinal veins which forms the left vena anonyma; * in C, cranial anastomosis between the posterior car- 

 dinal veins; z, caudal anastomosis between the same veins; K, kidney; S, suprarenal gland; T, testis. 



