Neuroanatomy: artery of Percheron: 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 · Neuroanatomy: artery of Percheron

Sample item

A patient has sudden drowsiness, vertical gaze palsy and memory loss. MRI shows bilateral paramedian thalamic infarcts with the rostral midbrain involved. Which vascular arrangement best explains this?

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

The answer and the reasoning

C. Occlusion of a single trunk from one P1 segment supplying both thalami

In some people one posterior cerebral P1 segment gives a single artery of Percheron that supplies both paramedian thalami and the rostral midbrain. Its occlusion causes bilateral thalamic infarcts with somnolence, vertical gaze palsy and amnesia. The other vessels supply the internal capsule and basal ganglia region.

Option by option

  • A. Occlusion of both anterior choroidal arteries

    The anterior choroidal artery supplies the posterior limb of the internal capsule and optic tract.

  • B. Occlusion of both lenticulostriate arteries

    Lenticulostriate arteries supply the basal ganglia and internal capsule, not the paramedian thalami.

  • C. Occlusion of a single trunk from one P1 segment supplying both thalami (correct)

    Correct. One occluded trunk can infarct both paramedian thalami.

  • D. Occlusion of the recurrent artery of Heubner

    The recurrent artery of Heubner supplies the anterior limb of the internal capsule and caudate head.

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 Anatomy question

What is the answer to this Anatomy question?

The best answer is C, Occlusion of a single trunk from one P1 segment supplying both thalami. In some people one posterior cerebral P1 segment gives a single artery of Percheron that supplies both paramedian thalami and the rostral midbrain.

Why is "Occlusion of both anterior choroidal arteries" not the answer?

The anterior choroidal artery supplies the posterior limb of the internal capsule and optic tract.

Why is "Occlusion of both lenticulostriate arteries" not the answer?

Lenticulostriate arteries supply the basal ganglia and internal capsule, not the paramedian thalami.

Why is "Occlusion of the recurrent artery of Heubner" not the answer?

The recurrent artery of Heubner supplies the anterior limb of the internal capsule and caudate head.

What concept does this question test?

It tests Neuroanatomy: artery of Percheron in Anatomy. Its occlusion causes bilateral thalamic infarcts with somnolence, vertical gaze palsy and amnesia. The other vessels supply the internal capsule and basal ganglia region.

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 Neuroanatomy: artery of Percheron?

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.