Coronary sinus

The coronary sinus is the major coronary vein. It returns the majority of the left ventricular blood flow to the right atrium.

The coronary sinus courses along the posterior wall of the left atrium into the left atrioventricular groove. It normally drains into the right atrium. The ostium of the coronary sinus is partially covered by the thebesian valve.

Veins draining into the coronary sinus are highly variable, but usually include:

The coronary sinus develops from one of the two sinus horns of the sinus venosum. The other horn becomes part of the right atrium. The right venous valve of the sinus venosum develops into the thebesian valve and the Eustachian valve.

  • the coronary sinus may act as a conduit between a persistent left superior vena cava and the right atrium
  • rarely, the coronary sinus may drain into the left atrium, causing a left-to-right shunt (or right-to-left in cases of right heart failure)

The coronary sinus may be involved in a number of different procedures or pathologic processes:

Thoracic anatomy
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Article information

rID: 32061
Systems: Cardiac, Vascular
Section: Anatomy
Synonyms or Alternate Spellings:

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