The right coronary artery usually bifurcates in an area of the posterior aspect of the heart known as the "crux cordis" giving origin to two terminal branches: the posterior interventricular artery (anatomical term) and the posterolateral artery. The posterior interventricular artery is better know to clinicians as the "posterior descending artery" or PDA.
The PDA descends towards the apex cordis where it ends. It gives off several small ventricular branches, but its most important branches are the septal perforators. These branches dive deep and provide blood supply to the posterior 1/3rd of the interventricular septum.
The PDA may present with a number of anatomical variations, including:
|• arising from the circumflex artery (and absence of the posterolateral artery)
• arising from the first septal perforator of the anterior interventricular artery
• arising from the second diagonal artery
• arising from anterior interventricular artery
• being double, with one PDA arising from the circumflex artery, and another from the right coronary artery, etc.
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