Thorax: coronary dominance: practice question

A Anatomy question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Anatomy · Thorax: coronary dominance

Sample item

A 62-year-old man has chest pain with ST elevation in leads II, III and aVF. Coronary angiography shows occlusion of the artery that gives off the posterior interventricular branch. In about 70% of people this branch arises from which vessel?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Right coronary artery

Coronary dominance is defined by the artery that gives the posterior interventricular (descending) artery at the crux of the heart. In about 70% of people this is the right coronary artery (right dominant), in about 10% the left circumflex, and the rest are balanced. Occlusion therefore produces an inferior wall infarct.

Option by option

  • A. Left circumflex artery

    The left circumflex gives this branch in only about 10% (left dominant).

  • B. Right coronary artery (correct)

    Correct. The right coronary artery gives the posterior interventricular branch in right-dominant hearts.

  • C. Left anterior descending artery

    The left anterior descending artery runs in the anterior interventricular groove and supplies the anterior wall and septum.

  • D. Left marginal artery

    The left marginal branch supplies the obtuse margin of the left ventricle and is not the source of the posterior interventricular artery.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Anatomy questions

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is B, Right coronary artery. Coronary dominance is defined by the artery that gives the posterior interventricular (descending) artery at the crux of the heart.

Why is "Left circumflex artery" not the answer?

The left circumflex gives this branch in only about 10% (left dominant).

Why is "Left anterior descending artery" not the answer?

The left anterior descending artery runs in the anterior interventricular groove and supplies the anterior wall and septum.

Why is "Left marginal artery" not the answer?

The left marginal branch supplies the obtuse margin of the left ventricle and is not the source of the posterior interventricular artery.

What concept does this question test?

It tests Thorax: coronary dominance in Anatomy. In about 70% of people this is the right coronary artery (right dominant), in about 10% the left circumflex, and the rest are balanced. Occlusion therefore produces an inferior wall infarct.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Thorax: coronary dominance?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.