Embryology: Pierre Robin sequence: 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 · Embryology: Pierre Robin sequence

Sample item

A newborn has a small receding chin and airway obstruction when supine, with a wide U-shaped cleft of the posterior palate. Why does the palate fail to close?

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

The answer and the reasoning

B. A small mandible leaves the tongue high between the palatal shelves

In the Pierre Robin sequence early mandibular hypoplasia keeps the tongue posteriorly and superiorly, where it blocks elevation and fusion of the palatal shelves. This gives a U-shaped secondary palate cleft, and the tongue base also obstructs the airway.

Option by option

  • A. Failure of the medial nasal and maxillary prominences to fuse

    Failure of these prominences to fuse causes a cleft lip, not a posterior palate cleft.

  • B. A small mandible leaves the tongue high between the palatal shelves (correct)

    Correct. Mandibular hypoplasia traps the tongue between the shelves and prevents fusion.

  • C. Failure of the intermaxillary segment to form the primary palate

    A defect of the intermaxillary segment causes an anterior (primary palate) cleft.

  • D. Premature ossification of the palatal shelves

    The shelves are not ossified prematurely, and the mechanism is mechanical interference.

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 B, A small mandible leaves the tongue high between the palatal shelves. In the Pierre Robin sequence early mandibular hypoplasia keeps the tongue posteriorly and superiorly, where it blocks elevation and fusion of the palatal shelves.

Why is "Failure of the medial nasal and maxillary prominences to fuse" not the answer?

Failure of these prominences to fuse causes a cleft lip, not a posterior palate cleft.

Why is "Failure of the intermaxillary segment to form the primary palate" not the answer?

A defect of the intermaxillary segment causes an anterior (primary palate) cleft.

Why is "Premature ossification of the palatal shelves" not the answer?

The shelves are not ossified prematurely, and the mechanism is mechanical interference.

What concept does this question test?

It tests Embryology: Pierre Robin sequence in Anatomy. This gives a U-shaped secondary palate cleft, and the tongue base also obstructs the airway.

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 Embryology: Pierre Robin sequence?

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.