CORONARY ARTERIES

From: Ascending aorta
To: Myocardium

Right coronary artery.

Originates from the
anterior aortic sinus. It passes anteriorly
between the pulmonary trunk and the
right auricle to reach the atrioventricular
sulcus in which it runs down the anterior
surface of the right cardiac border and
then onto the inferior surface of the
heart.

It terminates at the junction of the
atrioventricular sulcus and the posterior
interventricular groove by anastomosing
with the circumlex branch of the left
coronary artery and giving off the posterior
interventricular (posterior descending)
artery. It supplies the right atrium and
part of the left atrium, the sinuatrial node
in 60% of cases, the right ventricle, the
posterior part of the interventricular septum
and the atrioventricular node in 80% of
cases.


Left coronary artery.

Arises from the left
posterior aortic sinus. It passes laterally,
posterior to the pulmonary trunk and
anterior to the left auricle to reach the
atrioventricular groove where it divides
into an anterior interventricular (formally
left anterior descending) artery and
circumlex branches. The circumlex
artery runs in the atrioventricular sulcus
around the left border of the heart to
anastomose with the right coronary
artery. The anterior interventricular artery
descends on the anterior surface of the
heart in the anterior interventricular
groove and around the apex of the
heart into the posterior interventricular
groove where it anastomoses with the
posterior interventricular branch of the
right coronary artery. The left coronary
artery supplies the left atrium, left
ventricle, anterior interventricular septum,
sinuatrial node in 40% of cases and the
atrioventricular node in 20%.


Dominance.

In approximately 10% of
hearts the posterior interventricular artery
arises from the circumlex artery (left
coronary) and then most of the left ventricle
and interventricular septum are supplied by
the left coronary artery. The heart is said to
have
left cardiac dominance.


Madusanka Bibile

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