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 i ...

, the coronary sinus () is a collection of

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated ...

s joined together to form a large vessel that collects

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...

from the

heart The heart is a muscular Organ (biology), 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 ca ...

muscle (

myocardium Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle tha ...

). It delivers deoxygenated blood to the right atrium, as do the

superior Superior may refer to: *Superior (hierarchy), something which is higher in a hierarchical structure of any kind Places *Superior (proposed U.S. state), an unsuccessful proposal for the Upper Peninsula of Michigan to form a separate state *Lake ...

and inferior venae cavae. It is present in all

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...

s, including humans. The coronary sinus drains into the right atrium, at the coronary sinus orifice, an opening between the inferior vena cava and the right atrioventricular orifice or tricuspid valve. It returns blood from the heart muscle, and is protected by a semicircular fold of the lining membrane of the auricle, the valve of coronary sinus (or valve of Thebesius). The sinus, before entering the atrium, 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 cardiac vein is somewhat constricted and furnished with a valve, known as the valve of Vieussens consisting of two unequal segments.

Structure

The coronary sinus starts at the junction of the great cardiac vein and the

oblique vein of the left atrium The oblique vein of the left atrium (oblique vein of Marshall) is a small vessel which descends obliquely on the back of the left atrium The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from ...

. The junction of the great cardiac vein and the coronary sinus is marked by the Vieussens valve. It is present in 65% to 87% of the population. The coronary sinus runs transversely in the left atrioventricular groove on the posterior aspect of the heart. The coronary sinus then drains into the posterior wall of right atrium. The orifice of the coronary sinus is located to the left of the orifice of inferior vena cava in the right atrium. The

valve of the coronary sinus In the anatomy of the heart, 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, at the orifice of the coronary sinus. It is situate ...

(also known as "Thebesian valve" is a thin, semilunar (half moon shape) valve located on the anteroinferior part of the opening into the right atrium. It is present in 73% to 86% of autopsied heart. * Tributaries : ** Great cardiac vein (run upwards in the anterior interventricular sulcus to the left

atrioventricular groove The coronary sulcus (also called coronary groove, auriculoventricular groove, atrioventricular groove, AV groove) is a groove on the surface of the heart at the base of right auricle that separates the atria from the ventricles. The structure c ...

to form the coronary sinus; ** Middle cardiac vein (ascends posterior interventricular sulcus to drain into coronary sinus); ** Small cardiac vein (accompanies right coronary artery in the right atrioventricular groove to drain into the right side of the coronary sinus; ** Posterior vein of left ventricle (acccompanies the left marginal artery, ascends the posterior wall of left ventricle to drain into the coronary sinus); ** Oblique vein of left atrium

Function

The coronary sinus receives blood mainly from the

small Small may refer to: Science and technology * SMALL, an ALGOL-like programming language * Small (anatomy), the lumbar region of the back * ''Small'' (journal), a nano-science publication * <small>, an HTML element that defines smaller text ...

, middle,

great Great may refer to: Descriptions or measurements * Great, a relative measurement in physical space, see Size * Greatness, being divine, majestic, superior, majestic, or transcendent People * List of people known as "the Great" *Artel Great (born ...

and oblique cardiac veins. It also receives blood from the

left marginal vein The great cardiac vein receives tributaries from the left atrium and from both ventricles: one, the left marginal vein, is of considerable size, and ascends along the left margin of the heart The heart is a muscular organ in most anima ...

and the left posterior ventricular vein. It drains into the right atrium. The anterior cardiac veins do not drain into the coronary sinus but drain directly into the right atrium. Some small veins known as Thebesian veins drain directly into any of the four chambers of the heart.

Clinical significance

Electrodes can be inserted into and through the coronary sinus to study the

electrophysiology Electrophysiology (from Greek , ''ēlektron'', "amber" etymology of "electron"">Electron#Etymology">etymology of "electron" , ''physis'', "nature, origin"; and , ''-logia'') is the branch of physiology that studies the electrical properties of bi ...

of the heart. This includes for a coronary sinus electrogram. The coronary sinus connects directly with the right atrium. It will dilate as a result of any condition that causes elevated right atrial pressure, such as pulmonary hypertension. Dilated coronary sinus is also seen in some congenital cardiovascular conditions, such as persistent left supervisor cava, and total anomalous pulmonary venous return.Gupta A, Mishra A, Shrivastava Y. "Repair of intracardiac total anomalous pulmonary venous return". ''Multimed Man Cardiothorac Surg.'' 2021 Mar 8;2021. .

Additional images

File:Gray480.png, Diagram showing completion of development of the parietal veins. File:Blausen 0261 CoronaryVessels Posterior.png, Posterior view of coronary circulation

References

External links