272 



THE DEVELOPMENT OF THE VASCULAR SYSTEM 



R. ant. cardinal vein 



R. post, cardinal vein 

 R. com. cardinal vein- 



Subclavian veini 

 R. vitelline vein 

 R. umbilical vein 

 R. post, cardinal vein. 



Mesonephros 

 R. subcardinal vein 



R. ischiadic vein 



Caudal vein' 



R. ant. cardinal vein 

 R. subclavian vei; 

 R. com. cardinal vek 



Inf. vena cava 



R. post, cardinal vein' 

 MesonepkroS' 

 R. subcardinal vein. 



Metanephros- 



R. ischiadic vein 

 R. caudal vein' 



Ext. jugtdar vein Int. jugular vein 



Suhclavian vein 



Com. cardinal vein 



Int. jugular vein L. vena anonyma 

 Ext. jugular vein I / Ant. hemi- 

 Subclavian vein\ )h!e''°h''y'°^ azygos vein 

 A \ Am J. / J'x/ Sup. vena 



Azygos vern^ Xi^ii I tWs^y cava 



Post, cardinal 



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 



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 .4, 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; 5, suprarenal gland; T, testis. 



tween the left vena anonyma and the right subclavian vein is known as the right 

 vena anonyma. The distal portions of the anterior cardinals become the internal 



