sinus venosus

Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
Related to sinus venosus: cardinal vein

sinus ve·no·sus

The first chamber in the heart of fish, amphibians, reptiles, and the embryos of birds and mammals, which receives blood from the veins and contracts to force the blood into the atrium.

[New Latin sinus vēnōsus : Medieval Latin sinus, sinus + Latin vēnōsus, venous.]
References in periodicals archive ?
1) Some authors believe that the cause is congenital, owing to persistent vitelline veins and the sinus venosus.
5 days after conception, cells from an embryonic cardiac structure called the sinus venosus, which directs blood into the developing heart, began to migrate across the surface of the muscle.
During normal development, the anterior cardinal veins, which drain the head, neck, and arm, unite with the posterior cardinal vein in the very early embryonic stage and enter the heart as the right and left horns of the sinus venosus.