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.