Coronary Circulation Quiz: Arteries, Dominance and Venous Drainage

Review the vessels that supply and drain the myocardium. Coronary anatomy varies, so distinguish common patterns from the definition of coronary dominance.

8 questions · Estimated 6–8 minutes. Select your answer mentally, then open the explanation to check your reasoning.

1. Which coronary artery typically runs in the anterior interventricular sulcus?

  1. Left circumflex artery
  2. Right coronary artery
  3. Left anterior descending artery
  4. Posterior interventricular artery
Show answer and explanation

Answer: C. Left anterior descending artery

The left anterior descending (LAD), also called the anterior interventricular artery, runs in the anterior interventricular sulcus. It typically supplies much of the anterior left ventricular wall and anterior two-thirds of the interventricular septum.

2. Coronary dominance is principally defined by which artery gives rise to which vessel?

  1. Posterior descending artery
  2. Left anterior descending artery
  3. Left main coronary artery
  4. Ascending aorta
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Answer: A. Posterior descending artery

Dominance is principally determined by the origin of the posterior descending, or posterior interventricular, artery. It usually arises from the right coronary artery in right-dominant circulation and from the circumflex artery in left-dominant circulation.

3. The coronary sinus normally empties directly into which chamber?

  1. Left atrium
  2. Left ventricle
  3. Right ventricle
  4. Right atrium
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Answer: D. Right atrium

The coronary sinus collects much of the heart's venous blood and empties into the right atrium. Not all cardiac venous blood passes through it; some veins drain directly into cardiac chambers.

4. The right and left coronary arteries normally originate from:

  1. The pulmonary trunk
  2. The descending thoracic aorta
  3. The right and left aortic sinuses
  4. The coronary sinus
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Answer: C. The right and left aortic sinuses

The coronary arteries normally arise from the right and left aortic sinuses at the aortic root, just above the aortic valve. The coronary sinus is a venous channel and is not their source.

5. The left main coronary artery typically divides into which two major branches?

  1. LAD and left circumflex arteries
  2. Right marginal and posterior descending arteries
  3. Pulmonary and bronchial arteries
  4. Internal thoracic and intercostal arteries
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Answer: A. LAD and left circumflex arteries

The usual major branches of the left main coronary artery are the LAD and left circumflex arteries. Some people also have an intermediate branch, called the ramus intermedius, so branching is not identical in everyone.

6. Which artery typically follows the left atrioventricular groove?

  1. LAD
  2. Posterior descending artery
  3. Right marginal artery
  4. Left circumflex artery
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Answer: D. Left circumflex artery

The left circumflex artery follows the left AV groove between the left atrium and ventricle. Its branches commonly supply the lateral left ventricular wall; the extent of its territory varies with anatomy and dominance.

7. Blood flow through the coronary vessels supplying the left ventricular myocardium is generally greatest during:

  1. Atrial depolarization only
  2. Ventricular diastole
  3. Peak ventricular contraction
  4. A period when aortic pressure is zero
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Answer: B. Ventricular diastole

Left ventricular contraction compresses intramyocardial vessels, especially in the subendocardium. During diastole, this compression decreases while aortic pressure continues to drive coronary flow. The pattern differs somewhat in the lower-pressure right ventricle.

8. Which vein accompanies the LAD in the anterior interventricular sulcus?

  1. Small cardiac vein
  2. Middle cardiac vein
  3. Great cardiac vein
  4. Superior vena cava
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Answer: C. Great cardiac vein

The great cardiac vein accompanies the LAD in the anterior interventricular sulcus and ultimately drains into the coronary sinus. The middle cardiac vein instead follows the posterior interventricular sulcus.

Further reading