development of the venous system
Last reviewed 01/2018
The venous system is clearly differentiated by the end of the fourth week of gestation. At this stage, there are three pairs of key vessels returning blood to the sinus venosus of the heart:
- umbilical veins
- vitelline veins
- cardinal veins
Each of the these groups anastomoses with each other.
The development of each is considered in the submenu.