Thorax: phrenic nerve: 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 · Thorax: phrenic nerve

Sample item

A mediastinal mass produces paralysis of one hemidiaphragm. Which spinal cord segments supply the affected phrenic nerve?

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

The answer and the reasoning

C. C3-C5

The phrenic nerve arises chiefly from C3-C5 anterior rami and supplies the motor innervation of the diaphragm. The mnemonic is 'C3, 4, 5 keep the diaphragm alive'.

Option by option

  • A. T10-T12

    Lower thoracic roots are far below the phrenic origin.

  • B. T1-T3

    Thoracic roots supply intercostal nerves, not phrenic nerve.

  • C. C3-C5 (correct)

    Correct. C3-C5 form the phrenic nerve.

  • D. C1-C3

    These upper cervical roots do not provide the full phrenic nerve supply.

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.

More Anatomy questions

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is C, C3-C5. The phrenic nerve arises chiefly from C3-C5 anterior rami and supplies the motor innervation of the diaphragm.

Why is "T10-T12" not the answer?

Lower thoracic roots are far below the phrenic origin.

Why is "T1-T3" not the answer?

Thoracic roots supply intercostal nerves, not phrenic nerve.

Why is "C1-C3" not the answer?

These upper cervical roots do not provide the full phrenic nerve supply.

What concept does this question test?

It tests Thorax: phrenic nerve in Anatomy. The mnemonic is 'C3, 4, 5 keep the diaphragm alive'.

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 Thorax: phrenic nerve?

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.