This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax: Aerial supply, Subject name: Anatomy
Cardiac dominance is determined by coronary aery 
Select and explain. 
A. Supplying circulation to the SA node, B. Supplying circulation to the inferior poion of the interventricular septum, C. Supplying circulation to the inteatrial septum, D. Supplying circulation to the anterior poion of the interventricular septum
B: Supplying circulation to the inferior poion of the interventricular septum
Answer: B: Supplying circulation to the inferior poion of the interventricular septum 
Explanation: Cardiac dominance is determined by posterior inter ventricular aery which supplies postero inferior pa of interventricular septum. Mostly this a branch of RCA so right cardiac dominance(65% of population) If posterior inter ventricular aery arise from left coronary aery, then it is left cardiac dominance in 10% of population(bad prognosis) Multiple PIVA one from right side one from left side that is co -dominance in 25% of population.