 Posterior interventricular sulcus

The posterior interventricular sulcus is an external groove marking the meeting of the right ventricle and left ventricle on the posterior/inferior aspect of the heart. It provides a surface route for the posterior descending artery and middle cardiac vein toward the cardiac apex.^[ref]

Three objects must be distinguished when reading an anatomical drawing: the posterior interventricular sulcus is the groove, the vessels are structures within or along it, and the interventricular septum is the partition inside the heart. Following the groove toward the cardiac apex locates a ventricular boundary on the surface; it does not open a communication between the two ventricular cavities.

A useful dissection exercise is to identify the middle cardiac vein by tracing it back toward the coronary sinus, then compare its route with the neighboring posterior descending artery. The two vessels can occupy a common corridor while transporting blood in different directions. The origin of the posterior descending artery also varies with coronary dominance; the position of the groove does not by itself identify the supplying coronary artery. The posterior interventricular sulcus is therefore a stable anatomical landmark for describing a variable vascular network.