BACKGROUND: The ductus venosus (DV) and the intrahepatic branches of the portal vein are arranged as parallel vessels. Blood shunting through the DV ensures fetal survival during periods of stress. The availability of a suitable animal model with similar structure and function to the human fetus would greatly improve the understanding of DV function. The anatomical and histological structure of the DV has not been thoroughly investigated in non-human primate species. METHODS: Morphological investigations were performed on eight marmoset (Callithrix jacchus jacchus) at 112.5 +/- 5.5 days gestational age (mean +/- SEM) and four near-term (165 days) cynomolgus (Macaca fascicularis) fetuses. RESULTS: The DV drains into the collectus venosus. An asymmetrical muscular lip forms a contractile element of the isthmic portion of the DV. A spherical 'dividing' eminence was found on the dorsal wall of the venous collector just above the outlet of the DV in marmoset fetuses. CONCLUSIONS: Our findings regarding the structure of the DV in cynomolgus and marmoset fetuses were generally in agreement with previous descriptions of the morpho-histological structure of the DV in human fetuses.
