Anatomy of the coronary circulation

Our hearts are responsible for sending blood throughout our body and bringing it back to our lungs in a constant exchange of oxygenated and deoxygenated blood.

Here at Osmosis, we also think your hearts are responsible for ‘starting with the heart’ and showing us love every time you watch one of our videos!

But remember, the heart itself also needs its own blood supply, called the coronary circulation, which it gets from the right and left coronary arteries.

The coronary arteries are embedded in fat, and course across the surface of the heart just deep to the epicardium.

Let’s begin with the right coronary artery or RCA, which has its origin in the right aortic sinus and passes to the right side of the pulmonary trunk.

Close to its origin, the RCA gives a sinoatrial nodal branch, which supplies the sinoatrial node. The RCA then descends in the coronary sulcus.

Along the way, it gives off the right marginal branch, which gets close to the apex, but doesn’t reach it and supplies the right border of the heart.

After giving this branch, the RCA turns to the left and continues its journey in the coronary sulcus posteriorly.

Here, the RCA gives yet another branch, the atrioventricular nodal branch, which supplies the AV node.

The RCA usually gives the posterior interventricular branch which descends in the posterior interventricular groove.

This branch supplies areas of both ventricles and sends perforating interventricular septal branches into the IV septum.

Finally, the terminal branch of the RCA continues for a short distance in the coronary sulcus.

The left coronary artery or LCA originates from the left aortic sinus and passes between the left auricle and the left side of the pulmonary trunk and gets in the coronary sulcus.

At the superior end of the anterior interventricular or IV groove, the LCA divides into two branches: the anterior interventricular or IV branch, sometimes called the left anterior descending or LAD and the circumflex branch.

The anterior IV branch passes through the anterior IV groove to the apex, where it turns around the inferior border of the heart and typically anastomoses with the posterior IV branch of the RCA.