[Origin of the common pulmonary vein, septation of the primary sinus venosus atrial situs and theory of the "sinus man"].

Situated at the entry to the heart, the sinus venosus regulates at an early stage the distribution of the veins. Originally symmetrical, it receives on either side an omphalomesenteric vein, a common cardinal vein (duct of Cuvieri, ductus cuvieri) and a common pulmonary vein. This symmetrical pattern disappears with the obliteration of the rough right pulmonary vein and the invagination of the left ductus cuvieri into the sinusal cavity.