Neck: fascial spaces: 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 · Neck: fascial spaces

Sample item

A child with a retropharyngeal infection develops fever, chest pain and widening of the mediastinum on radiography. Pus has tracked between the alar fascia and the prevertebral fascia. Which space is infected and why is it described as dangerous?

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

The answer and the reasoning

B. The danger space, which extends from the skull base through the posterior mediastinum to the diaphragm

The danger space lies between the alar fascia and the prevertebral fascia and has no lower limit until the diaphragm, so infection reaches the posterior mediastinum rapidly. The retropharyngeal space proper lies in front of the alar fascia and ends in the superior mediastinum where the alar fascia fuses with the visceral fascia. Mediastinitis is a lethal complication.

Option by option

  • A. The parapharyngeal space, which ends at the hyoid bone

    The parapharyngeal space lies lateral to the pharynx and extends from the skull base to the hyoid, but the pus here lies behind the pharynx.

  • B. The danger space, which extends from the skull base through the posterior mediastinum to the diaphragm (correct)

    Correct. The danger space is continuous with the posterior mediastinum and allows rapid spread of infection.

  • C. The pretracheal space, which extends into the anterior mediastinum

    The pretracheal space lies in front of the trachea, not between the alar and prevertebral fasciae.

  • D. The retropharyngeal space proper, which continues to the diaphragm in front of the alar fascia

    The retropharyngeal space proper ends in the superior mediastinum and does not reach the diaphragm.

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, The danger space, which extends from the skull base through the posterior mediastinum to the diaphragm. The danger space lies between the alar fascia and the prevertebral fascia and has no lower limit until the diaphragm, so infection reaches the posterior mediastinum rapidly.

Why is "The parapharyngeal space, which ends at the hyoid bone" not the answer?

The parapharyngeal space lies lateral to the pharynx and extends from the skull base to the hyoid, but the pus here lies behind the pharynx.

Why is "The pretracheal space, which extends into the anterior mediastinum" not the answer?

The pretracheal space lies in front of the trachea, not between the alar and prevertebral fasciae.

Why is "The retropharyngeal space proper, which continues to the diaphragm in…" not the answer?

The retropharyngeal space proper ends in the superior mediastinum and does not reach the diaphragm.

What concept does this question test?

It tests Neck: fascial spaces in Anatomy. The retropharyngeal space proper lies in front of the alar fascia and ends in the superior mediastinum where the alar fascia fuses with the visceral fascia. Mediastinitis is a lethal complication.

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 Neck: fascial spaces?

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.