Neuroanatomy: medial medullary 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: medial medullary syndrome

Sample item

After a vertebral artery branch occlusion, a man's tongue deviates to the right on protrusion. He has left hemiparesis sparing the face and loss of vibration sense on the left. Which structure explains the tongue deviation?

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

The answer and the reasoning

C. Right hypoglossal nerve rootlets or nucleus in the medulla

In medial medullary syndrome the hypoglossal fibres, the pyramid and the medial lemniscus are damaged. The tongue deviates toward the side of the lesion because the intact genioglossus on the opposite side pushes it across, producing ipsilateral tongue weakness, contralateral hemiparesis sparing the face, and contralateral loss of vibration and position sense.

Option by option

  • A. Right glossopharyngeal nerve

    The glossopharyngeal nerve supplies taste and sensation to the posterior tongue and stylopharyngeus and does not move the tongue.

  • B. Right nucleus ambiguus

    The nucleus ambiguus supplies pharyngeal and laryngeal muscles, and its lesion causes dysphagia and hoarseness.

  • C. Right hypoglossal nerve rootlets or nucleus in the medulla (correct)

    Damage to the right hypoglossal nerve weakens the right genioglossus, so the left one pushes the tongue to the right.

  • D. Left hypoglossal nucleus

    A left hypoglossal lesion would deviate the tongue to the left.

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, Right hypoglossal nerve rootlets or nucleus in the medulla. In medial medullary syndrome the hypoglossal fibres, the pyramid and the medial lemniscus are damaged.

Why is "Right glossopharyngeal nerve" not the answer?

The glossopharyngeal nerve supplies taste and sensation to the posterior tongue and stylopharyngeus and does not move the tongue.

Why is "Right nucleus ambiguus" not the answer?

The nucleus ambiguus supplies pharyngeal and laryngeal muscles, and its lesion causes dysphagia and hoarseness.

Why is "Left hypoglossal nucleus" not the answer?

A left hypoglossal lesion would deviate the tongue to the left.

What concept does this question test?

It tests Neuroanatomy: medial medullary syndrome in Anatomy. The tongue deviates toward the side of the lesion because the intact genioglossus on the opposite side pushes it across, producing ipsilateral tongue weakness, contralateral hemiparesis sparing the face, and contralateral loss of vibration and position sense.

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 Neuroanatomy: medial medullary 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.