272 



THE DEVELOPMENT OF THE VASCULAR SYSTEM 



R. ant. cardinal vein 



R. post, cardinal vein 

 R. com. cardinal vein 



Subdavian vein' 

 R. vitelline vein 

 R. umbilical vein 

 R. post, cardinal vein 



Mesonephros 

 R. subcardinal vein 



R. isM.ai.ic vein 



Caudal vein 



R. ant. cardinal vein 

 R. subclavian vei, 

 R. com. cardinal vei; 



Inf. vena cava 



R. post, cardinal vein 

 Mesonephros 

 R. subcardinal vein 



Metanephros- 



R. ischiadic vein 

 R. caudal vein' 



Int. jugular vein L. vena anonyma 

 Ext. jugular vein t / /Ace. hemi- 

 $ubclavian vein 

 Azygos vein. 



Ext. jugular vein Int. jugular vein 



Subdavian vein 



Com. cardinal vein 



Azygos 

 vein 



Inf. vena 

 'cava 



Supracardinal 



vein 



Metanephros' 



Coronary sinus 

 Inf. vena cava 



Hepatic vein 



Hemi-azygos vein 



R. suprarenal vein 



R. renal vein 



L. renal vein 



Spermatic veins' 



Ext. iliac vein 

 Com. iliac vein 



azygos vein 

 Sup. vena 

 cava 



Ischiadic vein 



Caudal vein 



Hypogastric vein 



C Median sacral vein D 



FIG. 282. 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, vein of the plica 

 venae cavae:*, anastomosis between subcardinal veins; X, in C, anastomosis between anterior 

 cardinal veins which forms the left vena anonyma; *, in C, cranial anastomosis between the 

 azygos veins; z, caudal anastomosis between supracardinal veins; K, kidney; S, suprarenal 

 gland; T, testis. 



