The<unk>  (PIV), or<unk>  descending<unk>  (PDA), is an<unk>  running in the<unk><unk>  sulcus to the apex of the heart where it meets with the anterior<unk><unk> .  It supplies the<unk>  one third of the<unk>  septum.  The remaining anterior two thirds is supplied by the anterior<unk><unk>  which is a septal branch of the left anterior descending<unk> , which is a branch of left coronary<unk> .
It is typically a branch of the right coronary<unk>  (70%, known as right dominance). Alternatively, the PIV can be a branch of the circumflex coronary<unk>  (10%, known as left dominance) which itself is a branch of the left coronary<unk> . It can also be supplied by an anastomosis of the left and right coronary<unk>  (20%, known as co-dominance).  Variants have been reported.
Posterior interventricular artery
Internal carotid artery
Posterior communicating artery
Vertebral artery
Middle cerebral artery
Pontine arteries
Left circumflex artery
Left anterior descending artery