What is Coronary Sinus?

Coronary Sinus

The coronary sinus is one of the blood vessels that carries deoxygenated blood to the right atrium of the heart. Once blood enters the right atrium, it can be pumped through the heart and lungs to receive oxygen to return to the circulatory system to supply oxygen to the cells. The circulatory system relies on this cycle, in which blood is constantly moved through the body to remove waste and deliver essential nutrients and oxygen. In the case of a coronary sinus, the vein is drained from the coronary veins that run through the heart muscle, more formally known as the myocardium.

Anatomy of the coronary sinus

The coronary sinus is where the blood that flows into the coronary arteries passes when it returns to the right atrium.

As an image of running, it starts near the back side of the heart, turns under the mitral valve in the left atrium, and turns to the front side of the heart.

Then, we will join the right atrium from just below the atrioventricular node of the right atrium!

Function of Coronary Sinus valves

At the site where the coronary sinus connects to the right atrium, a valve known as the Phoebus valve controls blood flow to the heart and prevents blood from supporting the coronary sinus. The Thebian valve is also sometimes called the coronary sinus valve and takes the form of a small fold of tissue that allows blood to flow one way rather than another. The heart relies on a series of such one-way valves to maintain constant pressure and prevent backflow in the circulatory system.

At the point where it reaches the Thebis valve, the coronary sinus is quite large as a result of all the coronary veins that come together to drain into it. Depending on the person and circumstance, the vein may extend as far as the middle finger. Some patients may have larger or smaller veins in and around the heart, and heart muscles of varying sizes. Sometimes these changes can be dangerous, while other times they are not cause for concern.


Some people are born with birth defects that include the coronary sinus. These birth defects may require surgical correction in order for the heart to function. Most often, the coronary sinus is involved in an atrial septal defect, a medical problem that can lead to complications for the patient if not resolved.

Congenital anomalies of the CS had been categorized into following sorts:

Enlargement of the coronary sinus

Enlargement of the CS can also additionally end result from many received reasons, together with ventricular systole of the cardiac phase, coronary failure, cardiomyopathy, or fibrillation. Meanwhile, expanded blood waft quantity via anomalous congenital communications additionally reasons growth of the CS. Such anomalies are regularly divided into  groups, relying on the life of a left-to-proper shunt into the CS.

Without Left-to-Right Shunt into the coronary sinus

When the CS gets anomalous systemic venous go back, it turns into enlarged. Possible anatomic versions at some stage in this subgroup consist of a) continual left advanced vein (PLSVC) confluent with the CS, b) partial anomalous hepatic venous go back to the CS, and c) continuity of the inferior vein with the left advanced vein via the hemiazygos vein.

Persistent Left Superior vein

PLSVC is the most common thoracic venous anomaly. The incidence of PLSVC is stated to be 0.3% in healthy people and 4.4% in sufferers with congenital coronary heart circumstance. This anomaly outcomes from continual patency of the left anterior vein, which commonly obliterates at some stage in development. A PLSVC commonly drains into the right atrium via a dilated CS; however, it will additionally drain without delay into the right atrium in a few instances.

This anomaly commonly happens as an remoted lesion, however it are regularly associated with different congenital cardiac lesions, together with the PLSVC draining into the left atrium of the coronary heart, interatrial congenital coronary heart disorder, or unmarried atrium. The absence of the right advanced vein additionally accounts for approximately 20% of PLSVC. At some stage in this case, each of the left and proper brachiocephalic veins drain into the PLSVC.

Partial Anomalous Hepatic venous Return to the Coronary Sinus

An anomalous venous channel springing up from the liver pierces the diaphragm and consequently the pericardium. It then passes via the posterior factor of the center to join the CS.

Continuity of the Inferior vein with the Left Superior vein via the Hemiazygos Vein

In this circumstance, as opposed to connecting to the hepatic section, the suprarenal section of the growing inferior vein joins the hemiazygos vein, which reciprocally joins a PLSVC. The PLSVC in addition drains into the coronary sinus , main to growth. This circumstance also can be associated with different cardiac anomalies, together with extraordinary positioning of the center, partial inversion of the stomach viscera, or polysplenia.

Read also: Precordial Catch Syndrome: Symptoms, Cause and Treatments

With Left-to-Right Shunt into the CS

The CS also can emerge as enlarged while oxygenated blood shunts via anomalous communications. These communications are regularly divided into  groups: low- and high-pressure, left-to-proper shunts.

Communication of the sinus coronarius with the left atrium of the coronary heart

This communique can also additionally arise both not directly or without delay. In instances of oblique communique, an anomalous vein passes over the lateral wall of the left atrium of the coronary heart, and connects the CS with the left atrium of the coronary heart. Embryologically, this anomalous vein is taken under consideration to be a continual vessel connecting the left atrium of the coronary heart or vena pulmonalis to the cardinal venous machine in reaction to a partially obstructed CS ostium. Blood waft at some stage in this channel is expected to be at some stage in a left-to-proper route beneath neath physiological pressure.

Unroofed coronary sinus can be an unprecedented anomaly at some stage in which communique among the CS and consequently the left atrium of the coronary heart is made without delay as a result of the partial or entire absence of the CS roof. This entity is the rarest kind of atrial congenital coronary heart disorder and is commonly associated with PLSVC. This circumstance commonly happens with a left-to-proper shunt; however, if the PLSVC is attached to the CS, systemic blood can also be diverted to the left atrium of the coronary heart through the fenestration. This diversion can also additionally result in a proper-to-left shunt, which can also additionally cause cerebral emboli or mind abscesses.

Pulmonary venous Connection to the CS

This anomaly is both overall or subtotal bureaucracy, however overall anomalous pulmonary venous connection to the CS is that the greater not unusual place form. Under this circumstance, every of the pulmonary veins bureaucracy a pulmonary venous confluence that connects the CS.

Coronary Artery-Coronary Sinus Fistula

Coronary artery-coronary sinus fistula can be an unprecedented coronary arteriovenous fistula. This circumstance results in a high-pressure, left-to-proper shunt into the CS that is commonly dilated. The affected artery turns into elongated and tortuous, and an aneurysm can also additionally from time to time.

Absence of the coronary sinus

This circumstance is usually amid different anomalies, like a PLSVC linked to the left atrium of the coronary heart or an atrial congenital coronary heart disorder. There are 3 subdivisions supporting the kind of atrial congenital coronary heart disorder and consequently the life of extra anomalies.

The coronary arteries and associated sinuses can also become blocked. When this happens, the cause of the blockage must be determined through examination and screening so that the doctor can correct it. Testing often includes angiography, which injects tags and traces information about a patient’s vascular problems. Failure to correct the occlusion can damage the heart.

Leave a Comment

Your email address will not be published.