Cardiovascular system: Kussmaul sign: 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 system: Kussmaul sign

Sample item

In constrictive pericarditis the jugular venous pressure rises, instead of falling, during inspiration. What is the reason?

ALoss of atrial contraction flattens the venous waveformBThe tricuspid valve closes completely during inspirationCThe rigid pericardium isolates the heart from the fall in intrathoracic pressureDInspiration compresses the superior vena cava and obstructs venous drainage

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

The answer and the reasoning

C. The rigid pericardium isolates the heart from the fall in intrathoracic pressure

Normally inspiration lowers intrathoracic pressure, which is transmitted to the right atrium and draws more blood in, so the jugular pressure falls. In constrictive pericarditis the thickened pericardium prevents transmission of the pressure change, and the stiff heart cannot accommodate the extra venous return, so the jugular venous pressure rises (Kussmaul sign).

Option by option

A. Loss of atrial contraction flattens the venous waveform
Atrial contraction is preserved in sinus rhythm, and its loss would not make the pressure rise on inspiration.
B. The tricuspid valve closes completely during inspiration
The tricuspid valve remains functional, and the problem is the stiff, restricted filling.
C. The rigid pericardium isolates the heart from the fall in intrathoracic pressure (correct)
Correct. The rigid pericardium blocks the transmission of the inspiratory pressure fall.
D. Inspiration compresses the superior vena cava and obstructs venous drainage
Inspiration does not compress the vena cava in this way.

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.

Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is C, The rigid pericardium isolates the heart from the fall in intrathoracic pressure. Normally inspiration lowers intrathoracic pressure, which is transmitted to the right atrium and draws more blood in, so the jugular pressure falls.

Why is "Loss of atrial contraction flattens the venous waveform" not the answer?

Atrial contraction is preserved in sinus rhythm, and its loss would not make the pressure rise on inspiration.

Why is "The tricuspid valve closes completely during inspiration" not the answer?

The tricuspid valve remains functional, and the problem is the stiff, restricted filling.

Why is "Inspiration compresses the superior vena cava and obstructs venous dr…" not the answer?

Inspiration does not compress the vena cava in this way.

What concept does this question test?

It tests Cardiovascular system: Kussmaul sign in Physiology. In constrictive pericarditis the thickened pericardium prevents transmission of the pressure change, and the stiff heart cannot accommodate the extra venous return, so the jugular venous pressure rises (Kussmaul sign).

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 system: Kussmaul sign?

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.