154 



EDWARD MCCRADY, JR. 



The two umbilical veins have fused into a single vessel from 

 the umbilicus craniad to the liver. Within the liver a new 

 vessel of hepatic origin, the ductus venosus, drains this 

 common umbilical into the postcava (right omphalomesenteric 

 portion). 



The left subcardinal anterior to the anastomosis is a very 

 small vessel which will be preserved only on account of its 



rtfht 



duct 



posfcardinal 

 postcava 



cardinal 

 collaterals 



external 

 iliac ~ 



renal 



spermatic or 

 ovar'ion (f>ubc.) 

 postcardinG I 

 r 



internal 

 iliac 



Fig. 50 Eeconstruction of principal veins in stage 33 (slightly modified from 

 McClure, '06). 



association with the developing left adrenal gland. The right 

 adrenal gland is drained by a branch directly from the 

 postcava which is at this level the right subcardinal. 



The fact that the right omphalomesenteric vein does not 

 become broken up into sinusoids as the left does, results in 

 its being transformed into most of the hepatic portion of the 



