Library · Anatomy
Coronary dominance
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The heart is supplied by two coronary arteries, the right and the left. So far, everyone is alike. The difference lies lower down, on the inferior surface of the heart, the one resting against the diaphragm: that area is supplied by the posterior descending artery, and it does not arise from the same side in everyone.
This is called dominance. If the posterior descending artery comes off the right coronary artery, the person is said to be right dominant, and that is the case in seven or eight out of ten. If not, the person is left dominant, and when both arteries supply that area, codominant.
It matters because of a subtle detail: small branches come off the dominant artery to supply the atrioventricular node, the electrical relay that passes the impulse from the atria to the ventricles. Each person's dominance is seen when the coronary arteries are studied at catheterization.
In brief
Dominance names which coronary artery gives off the posterior descending artery and supplies the inferior wall of the heart.
The underside of the heart is not supplied by the same side in everyone.
It can be right, left or codominant: in 70 to 80 percent of people the posterior descending artery arises from the right coronary artery.
Small branches of the dominant artery supply the atrioventricular node.
Dominance is determined by viewing the coronary arteries at catheterization.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingCardiac Dominance, StatPearlsPublished
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