Great cardiac vein

The great cardiac vein originates near the cardiac apex in the anterior interventricular sulcus, running alongside the anterior interventricular (left anterior descending) artery. It ascends in this groove toward the base of the heart, then curves leftward at the coronary sulcus, where it forms the base of the triangle of Brocq and Mouchet with the bifurcating branches of the left coronary artery. In this region, the vein is usually superficial to the arteries in the majority of cases.

The great cardiac vein continues posteriorly in the left atrioventricular (coronary) sulcus, where it becomes the main tributary of the coronary sinus. Along its course, it receives blood from the left atrium and both ventricles, including the left marginal vein (which drains the lateral wall of the left ventricle) in most cases.

The diameter of the great cardiac vein varies, with reported measurements around 5–7 mm at the level of the Vieussens valve, and it is often in close proximity to the mitral valve annulus and the left atrium.