Cranial caval vein 



Thoracoabdominal network 



Intercostal veins 



Internal mammary vein 



Caudal caval vein 

 Portal vein 



Epigastric superficial vein "^Ka% 



Epigastric internal vein 



\ Dural and cerebral sinuses 



') 

 J) 



y 



SI 



J^V- Vertebral vein system 



Segmental communications 



, I AJ7 " rt 8 I Thoracic longitudinal 



lf.Ql left \ veins 



Tubo-ovarian pampiniform 

 plexus 



S}\ Caudal caval vein 



Ascending lumbar vein 

 Mesenteric inferior 



^t\ VI -A Sacral vein 



\WJjjf~ |~ " ~ Superior rectal 



Medial rectal j plexuses 

 Inferior rectal I 

 Pudendal vein 



Caudal caval system. 



Uterovenal visceral circulation. 



Portal circulation. 



The anterior parietal abdomino-thoracal communications. 



Retroperitoneal and retropleural communications to the cranial caval system. 



Vertebral vein system to the cerebral sinuses. 



fig. 4. See legend on facing page. 



