Neurology: uncal herniation signs: practice question

A General Medicine 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 Medicine · Neurology: uncal herniation signs

Sample item

A patient with a large right hemispheric haematoma becomes drowsy. The right pupil is now dilated and unreactive with the eye deviated down and out, and left hemiparesis develops. Which herniation is responsible?

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

The answer and the reasoning

A. Uncal (transtentorial) herniation

The medial temporal uncus herniates over the tentorial edge and compresses the ipsilateral oculomotor nerve, causing a dilated pupil and down-and-out eye. The cerebral peduncle is also compressed, giving contralateral hemiparesis, or sometimes ipsilateral weakness through the Kernohan notch.

Option by option

  • A. Uncal (transtentorial) herniation (correct)

    Correct. Third nerve compression with hemiparesis indicates uncal herniation.

  • B. Upward cerebellar herniation

    Upward herniation follows posterior fossa mass effect with brainstem signs.

  • C. Subfalcine (cingulate) herniation

    Subfalcine herniation compresses the anterior cerebral artery and causes leg weakness.

  • D. Tonsillar herniation through the foramen magnum

    Tonsillar herniation compresses the medulla, causing respiratory arrest.

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 General Medicine question

What is the answer to this General Medicine question?

The best answer is A, Uncal (transtentorial) herniation. The medial temporal uncus herniates over the tentorial edge and compresses the ipsilateral oculomotor nerve, causing a dilated pupil and down-and-out eye.

Why is "Upward cerebellar herniation" not the answer?

Upward herniation follows posterior fossa mass effect with brainstem signs.

Why is "Subfalcine (cingulate) herniation" not the answer?

Subfalcine herniation compresses the anterior cerebral artery and causes leg weakness.

Why is "Tonsillar herniation through the foramen magnum" not the answer?

Tonsillar herniation compresses the medulla, causing respiratory arrest.

What concept does this question test?

It tests Neurology: uncal herniation signs in General Medicine. The cerebral peduncle is also compressed, giving contralateral hemiparesis, or sometimes ipsilateral weakness through the Kernohan notch.

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 Neurology: uncal herniation signs?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.