In the

anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having it ...

of the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...

, the valve of the coronary sinus (also called the Thebesian valve, after Adam Christian Thebesius) is a semicircular fold of the lining membrane of the right

atrium Atrium may refer to: Anatomy * Atrium (heart), an anatomical structure of the heart * Atrium, the genital structure next to the genital aperture in the reproductive system of gastropods * Atrium of the ventricular system of the brain * Pulmona ...

, at the orifice of the

coronary sinus In anatomy, the coronary sinus () is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena ...

. It is situated at the base of the

inferior vena cava The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of th ...

. The

valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...

may vary in size, or be completely absent.P. Felle, J. G. Bannigan. ''Anatomy of the valve of the coronary sinus (thebesian valve)''. Clinical Anatomy. Vol. 7 (1), 10-12
Abstract
/ref> It may prevent the regurgitation of blood into the sinus during the contraction of the atrium. This valve may be double or it may be cribriform (containing numerous small holes).

References

{{Authority control Cardiac anatomy