Cardiovascular: Korotkoff sounds: practice question

A Physiology 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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Physiology · Cardiovascular: Korotkoff sounds

Sample item

While measuring blood pressure with a cuff, the examiner hears tapping sounds that begin when cuff pressure falls to 120 mmHg and disappear when it falls to 80 mmHg. Why do the sounds vanish below 80 mmHg?

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

The answer and the reasoning

A. Flow through the artery returns to laminar and silent when the cuff no longer narrows it

Between systolic and diastolic pressures the cuff partly compresses the brachial artery, and blood jets through the narrowed segment at high velocity, giving a high Reynolds number, turbulence and Korotkoff sounds. When cuff pressure falls below diastolic the vessel stays open, flow is laminar and silent. The point at which the sounds vanish marks diastolic pressure.

Option by option

  • A. Flow through the artery returns to laminar and silent when the cuff no longer narrows it (correct)

    Correct. Laminar flow in an unobstructed artery is silent.

  • B. Blood flow stops during diastole

    Flow continues through diastole in a normal peripheral artery.

  • C. The artery collapses completely below diastolic pressure

    Collapse of the artery happens when cuff pressure is above systolic and stops flow, so no sounds are heard.

  • D. The pulse pressure becomes zero

    Pulse pressure is the difference between 120 and 80 and does not become zero.

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.

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Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is A, Flow through the artery returns to laminar and silent when the cuff no longer narrows it. Between systolic and diastolic pressures the cuff partly compresses the brachial artery, and blood jets through the narrowed segment at high velocity, giving a high Reynolds number, turbulence and Korotkoff sounds.

Why is "Blood flow stops during diastole" not the answer?

Flow continues through diastole in a normal peripheral artery.

Why is "The artery collapses completely below diastolic pressure" not the answer?

Collapse of the artery happens when cuff pressure is above systolic and stops flow, so no sounds are heard.

Why is "The pulse pressure becomes zero" not the answer?

Pulse pressure is the difference between 120 and 80 and does not become zero.

What concept does this question test?

It tests Cardiovascular: Korotkoff sounds in Physiology. When cuff pressure falls below diastolic the vessel stays open, flow is laminar and silent. The point at which the sounds vanish marks diastolic pressure.

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 Cardiovascular: Korotkoff sounds?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.