Neuroimaging: uncal herniation: practice question

A Radiology 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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Radiology · Neuroimaging: uncal herniation

Sample item

A patient with a large right temporal haematoma has a dilated right pupil. Which CT finding indicates descending transtentorial uncal herniation?

ADilated temporal horns of the lateral ventriclesBEffacement of the right suprasellar cistern with medial displacement of the uncusCMidline shift with the cingulate gyrus pushed beneath the falxDDownward displacement of the cerebellar tonsils below the foramen magnum

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

The answer and the reasoning

B. Effacement of the right suprasellar cistern with medial displacement of the uncus

In uncal herniation the medial temporal lobe is pushed over the tentorial edge, compressing the suprasellar and ambient cisterns and the third nerve, which causes the dilated pupil. Subfalcine herniation is the cingulate gyrus under the falx, and tonsillar herniation is through the foramen magnum. Dilated temporal horns indicate hydrocephalus.

Option by option

A. Dilated temporal horns of the lateral ventricles
Dilated temporal horns suggest obstructive hydrocephalus.
B. Effacement of the right suprasellar cistern with medial displacement of the uncus (correct)
Correct. Cisternal effacement with medial uncal displacement indicates uncal herniation.
C. Midline shift with the cingulate gyrus pushed beneath the falx
This describes subfalcine herniation.
D. Downward displacement of the cerebellar tonsils below the foramen magnum
This describes tonsillar herniation.

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 Radiology question

What is the answer to this Radiology question?

The best answer is B, Effacement of the right suprasellar cistern with medial displacement of the uncus. In uncal herniation the medial temporal lobe is pushed over the tentorial edge, compressing the suprasellar and ambient cisterns and the third nerve, which causes the dilated pupil.

Why is "Dilated temporal horns of the lateral ventricles" not the answer?

Dilated temporal horns suggest obstructive hydrocephalus.

Why is "Midline shift with the cingulate gyrus pushed beneath the falx" not the answer?

This describes subfalcine herniation.

Why is "Downward displacement of the cerebellar tonsils below the foramen mag…" not the answer?

This describes tonsillar herniation.

What concept does this question test?

It tests Neuroimaging: uncal herniation in Radiology. Subfalcine herniation is the cingulate gyrus under the falx, and tonsillar herniation is through the foramen magnum. Dilated temporal horns indicate hydrocephalus.

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 Neuroimaging: uncal herniation?

Learn signs with the image, and the disease they point to. Then use the flashcards and the other Radiology 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.