Posterior interventricular branch of right coronary artery

Where does the posterior interventricular artery run?

It follows the posterior interventricular sulcus down to the apex. (OpenStax A&P 2e, 19.1; StatPearls, Heart Veins; Gray 1918, 2. The Aorta)

It branches off at the crux cordis, where the right coronary artery also gives off the right posterolateral artery. Angiographers use the crux cordis as a landmark. (StatPearls, Heart Arteries)

What does the posterior interventricular artery supply?

Its branches supply the interventricular septum and parts of both ventricles. Its septal branches supply the back third of the septum. (OpenStax A&P 2e, 19.1; StatPearls, Heart Arteries)

It is a terminal branch of the right coronary artery, as is the right posterolateral artery. (StatPearls, Heart Arteries)

Where does the posterior interventricular artery meet other vessels?

Small branches of the anterior interventricular artery connect with its branches. The ends of the two arteries join in the posterior interventricular groove in about 90% of hearts. (OpenStax A&P 2e, 19.1; StatPearls, Heart Left Anterior Descending Artery)

The middle cardiac vein runs beside it in the posterior interventricular sulcus and drains the area it supplies. (OpenStax A&P 2e, 19.1; StatPearls, Heart Veins)

Which artery gives rise to the posterior descending artery?

The artery that gives rise to the PDA sets a heart’s dominance. The StatPearls article on the heart arteries has it come from the right coronary artery in at least 70% of hearts (right dominant), from the left coronary artery in about 10% (left dominant), and from both in 20% (codominant). (StatPearls, Heart Arteries)

Where the sources differ

The StatPearls articles give different shares for right dominance: at least 70% in the article on the heart arteries, over 70% in the article on the heart and pericardial cavity, and 85% in the article on cardiac muscle. (StatPearls, Heart Arteries, Heart and Pericardial Cavity and Cardiac Muscle)