Vascular surgery: why aneurysms favour the infrarenal aorta: practice question

A General Surgery 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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General Surgery · Vascular surgery: why aneurysms favour the infrarenal aorta

Sample item

The infrarenal segment of the abdominal aorta is the most common site of atherosclerotic aneurysm. Which feature of this segment contributes most?

AFewer elastin lamellae and sparse vasa vasorum in the wallBDirect jet injury from the renal arteriesCAbsence of an adventitial layer in this segmentDThickest media of the whole aorta, which rigidly resists dilatation

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

The answer and the reasoning

A. Fewer elastin lamellae and sparse vasa vasorum in the wall

The abdominal aorta has less elastin and fewer lamellar units than the thoracic aorta, and its wall is supplied by few vasa vasorum, so it is more prone to degeneration. Reflected pressure waves from the iliac bifurcation add to wall stress.

Option by option

A. Fewer elastin lamellae and sparse vasa vasorum in the wall (correct)
Correct. Reduced elastin and poor vasa vasorum nutrition weaken the wall.
B. Direct jet injury from the renal arteries
Flow from the renal arteries does not produce jet injury to the infrarenal wall.
C. Absence of an adventitial layer in this segment
The adventitia is present throughout the aorta.
D. Thickest media of the whole aorta, which rigidly resists dilatation
The infrarenal media is thinner than in the thoracic aorta, not thicker.

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 General Surgery question

What is the answer to this General Surgery question?

The best answer is A, Fewer elastin lamellae and sparse vasa vasorum in the wall. The abdominal aorta has less elastin and fewer lamellar units than the thoracic aorta, and its wall is supplied by few vasa vasorum, so it is more prone to degeneration.

Why is "Direct jet injury from the renal arteries" not the answer?

Flow from the renal arteries does not produce jet injury to the infrarenal wall.

Why is "Absence of an adventitial layer in this segment" not the answer?

The adventitia is present throughout the aorta.

Why is "Thickest media of the whole aorta, which rigidly resists dilatation" not the answer?

The infrarenal media is thinner than in the thoracic aorta, not thicker.

What concept does this question test?

It tests Vascular surgery: why aneurysms favour the infrarenal aorta in General Surgery. Reflected pressure waves from the iliac bifurcation add to wall stress.

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 Vascular surgery: why aneurysms favour the infrarenal aorta?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery 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.