Coronary sinus Information & Coronary sinus Links at HealthHaven.com

Vein: Coronary sinus
	Base and diaphragmatic surface of heart.
	Interior of right side of heart.
Latin	sinus coronarius
Gray's	subject #138 530
Source	great cardiac vein
Drains to	right atrium
Precursor	sinus venosus

The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the myocardium of the heart. It is present in humans and other animals.

The coronary sinus opens into the right atrium, between the inferior vena cava and the auriculo-ventricular opening. It returns the blood from the substance of the heart, and is protected by a semicircular fold of the lining membrane of the auricle, the coronary valve. ( valve of Thebesius). The sinus, before entering the auricle, is considerably dilated - nearly to the size of the end of the little finger. Its wall is partly muscular, and at its junction with the great coronary vein is somewhat constricted and furnished with a valve consisting of two unequal segments.- Gray 462

[edit] Location

It is located in the right atrium and runs transversely in the groove between the left atrium and ventricle on the posterior surface of the heart.

The coronary sinus orifice (opening) is just superior to the septal leaflet of the tricuspid valve. The coronary sinus orifice is also known as the ostium of the coronary sinus, and is guarded by the Thebesian valve.

[edit] Drainage

It receives blood mainly from the small, middle, great and oblique cardiac veins. It also receives blood from the left marginal vein and the left posterior ventricular vein. The anterior cardiac veins drain directly into the right atrium. (Some small veins drain into any of the four chambers of the heart.)

It drains into the right atrium on the posterior, inferior surface, medial to the inferior vena cava opening.