Sinus venosus

Sinus venosus
Interior of dorsal half of heart from a human embryo of about thirty days, frontal view. (Opening of sinus venosus labeled at center top.)
Human embryo with heart and anterior body-wall removed to show the sinus venosus and its tributaries. (Sinus venosus labeled at center left.)
Details
Carnegie stage	9
System	Cardiovascular system
Identifiers
Latin	sinus venosus cordis
TA98	A12.0.00.016
TA2	3911
TE	venosus_by_E5.11.1.3.2.0.4, E5.11.1.5.1.0.1 E5.11.1.3.2.0.4, E5.11.1.5.1.0.1
FMA	70303
Anatomical terminology [edit on Wikidata]

The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart.^{[1][verification needed]}

In mammals, the sinus venosus exists distinctly only in the embryonic heart where it is found between the two venae cavae; in the adult, the sinus venosus becomes incorporated into the wall of the right atrium to form a smooth part called the sinus venarum which is separated from the rest of the atrium by a ridge called the crista terminalis. In most mammals, the sinus venosus also forms the sinoatrial node and the coronary sinus.^{[1][verification needed]}