Great cardiac vein

Where does the great cardiac vein run?

It starts at the apex and climbs the anterior interventricular sulcus beside the anterior interventricular artery, toward the base of the left auricle. (StatPearls, Heart Veins)

At the left margin of the heart it turns onto the back. There it meets the oblique vein of the left atrium, and the two form the coronary sinus. (StatPearls, Heart Veins and Coronary Sinus)

The valve of Vieussens sits at its end, where the coronary sinus begins. (StatPearls, Coronary Sinus)

What does the great cardiac vein drain?

It drains the area that the anterior interventricular artery supplies, carrying blood from both ventricles and the left atrium toward the right atrium. (OpenStax A&P 2e, 19.1; StatPearls, Heart Veins)

It belongs to the greater cardiac venous system, which drains most of the blood from the heart muscle, and it is one of the tributaries of the coronary sinus. (StatPearls, Heart Veins)

Which veins lie near the great cardiac vein?

The oblique vein of the left atrium, which it meets at the start of the coronary sinus, has no valve at its junction with the sinus, where the other tributaries have one. (StatPearls, Coronary Sinus)

Does the great cardiac vein vary?

It and the coronary sinus show the most notable variations among the cardiac veins. It runs along the anterior interventricular sulcus as a rule, but in some people it runs inside the heart wall, which can hinder its flow. (StatPearls, Heart Veins)

Where the sources differ

The sources disagree on where the middle and small cardiac veins end. OpenStax lists them, with the posterior cardiac vein, as branches the great cardiac vein receives; the StatPearls articles have them draining into the coronary sinus itself. (OpenStax A&P 2e, 19.1; StatPearls, Coronary Sinus and Heart Veins)