Neuroanatomy: ventral pontine syndrome: 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: ventral pontine syndrome

Sample item

A 62-year-old woman has sudden right facial weakness involving the forehead, inability to abduct the right eye, and left-sided arm and leg weakness. Where is the lesion?

ARight ventral (basal) ponsBRight lateral medullaCRight midbrain baseDLeft ventral pons

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

The answer and the reasoning

A. Right ventral (basal) pons

Millard-Gubler syndrome is caused by a ventral pontine lesion that involves the exiting facial nerve fibres (ipsilateral lower motor neuron facial palsy including the forehead), the abducens fascicle (ipsilateral lateral rectus palsy) and the corticospinal tract before it decussates (contralateral hemiparesis). The side of cranial nerve signs gives the side of the lesion.

Option by option

A. Right ventral (basal) pons (correct)
Correct. Ipsilateral cranial nerve VI and VII palsies with contralateral hemiparesis localise to the ventral pons on the side of the cranial nerve signs.
B. Right lateral medulla
A lateral medullary lesion causes Horner syndrome, ataxia and crossed sensory loss, not these signs.
C. Right midbrain base
A midbrain base lesion causes an oculomotor palsy with contralateral hemiparesis (Weber syndrome).
D. Left ventral pons
A left pontine lesion would cause left cranial nerve palsies and right hemiparesis.

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 Anatomy question

What is the answer to this Anatomy question?

The best answer is A, Right ventral (basal) pons. Millard-Gubler syndrome is caused by a ventral pontine lesion that involves the exiting facial nerve fibres (ipsilateral lower motor neuron facial palsy including the forehead), the abducens fascicle (ipsilateral lateral rectus palsy) and the corticospinal tract before it decussates (contralateral hemiparesis).

Why is "Right lateral medulla" not the answer?

A lateral medullary lesion causes Horner syndrome, ataxia and crossed sensory loss, not these signs.

Why is "Right midbrain base" not the answer?

A midbrain base lesion causes an oculomotor palsy with contralateral hemiparesis (Weber syndrome).

Why is "Left ventral pons" not the answer?

A left pontine lesion would cause left cranial nerve palsies and right hemiparesis.

What concept does this question test?

It tests Neuroanatomy: ventral pontine syndrome in Anatomy. The side of cranial nerve signs gives the side of the lesion.

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: ventral pontine syndrome?

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.