Posterior descending artery
In the coronary circulation, the posterior descending artery, also called the posterior interventricular artery, is an artery running in the posterior [interventricular sulcus] to the apex of the heart where it meets with the left anterior descending artery also known as the anterior interventricular artery. The PDA supplies the posterior third of the interventricular septum. The remaining anterior two-thirds is supplied by the left anterior descending artery, which is a branch of left [coronary artery].
It is typically a branch of the right coronary artery. Alternately, the PDA can be a branch of the circumflex coronary artery which itself is a branch of the left coronary artery. It can also be supplied by an anastomosis of the left and right coronary artery.
Variants have been reported.
The anatomical position of the artery is not really posterior, but inferior. The terminology posterior is based on viewing the heart from the "Valentine" position, not by the heart's actual position in the body.