Cardiac dominance is based on ?
**Core Concept**
Cardiac dominance refers to the blood supply and innervation of the heart, with the majority of the heart muscle being supplied by a single coronary artery and receiving its innervation from the vagus nerve and sympathetic nervous system.
**Why the Correct Answer is Right**
The heart is dominated by the left coronary artery, which supplies approximately 80-85% of the heart muscle, including the left ventricle and the anterior two-thirds of the interventricular septum. The left coronary artery divides into the left anterior descending (LAD) and left circumflex (LCx) arteries, which further supply the heart muscle. The right coronary artery supplies the remaining 15-20% of the heart muscle, including the right ventricle and the posterior one-third of the interventricular septum.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to cardiac dominance.
**Option B:** This option is incorrect as the right coronary artery does not dominate the heart.
**Option C:** This option is incorrect as the left coronary artery, not the right, dominates the heart.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the left coronary artery is responsible for supplying the majority of the heart muscle, and its occlusion can lead to a larger area of myocardial infarction.
**Correct Answer: D. The left coronary artery.**