Thorax and diaphragm: 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 and diaphragm: phrenic nerve

Sample item

A patient with a subphrenic abscess and irritation of the diaphragmatic peritoneum complains of pain at the tip of the right shoulder. Which nerve explains this referred pain?

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

The answer and the reasoning

A. Phrenic nerve (C3, C4, C5)

The phrenic nerve arises from the ventral rami of C3 to C5 and supplies the diaphragm with motor fibres and sensation to the central diaphragmatic pleura and peritoneum. The skin over the shoulder tip is supplied by C3 and C4 through the supraclavicular nerves, so diaphragmatic irritation is felt there. The peripheral diaphragm is supplied by the lower intercostal nerves, whose irritation causes pain in the lower chest or abdominal wall.

Option by option

  • A. Phrenic nerve (C3, C4, C5) (correct)

    Correct. Shared C3 to C5 roots explain the shoulder-tip pain.

  • B. Long thoracic nerve

    The long thoracic nerve is motor to serratus anterior and carries no pain fibres.

  • C. Vagus nerve

    The vagus nerve carries no sensation from the diaphragmatic peritoneum that is referred to the shoulder.

  • D. Intercostal nerves T7 to T11

    The lower intercostal nerves supply the periphery of the diaphragm and give pain in the lower chest and abdominal wall.

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 A, Phrenic nerve (C3, C4, C5). The phrenic nerve arises from the ventral rami of C3 to C5 and supplies the diaphragm with motor fibres and sensation to the central diaphragmatic pleura and peritoneum.

Why is "Long thoracic nerve" not the answer?

The long thoracic nerve is motor to serratus anterior and carries no pain fibres.

Why is "Vagus nerve" not the answer?

The vagus nerve carries no sensation from the diaphragmatic peritoneum that is referred to the shoulder.

Why is "Intercostal nerves T7 to T11" not the answer?

The lower intercostal nerves supply the periphery of the diaphragm and give pain in the lower chest and abdominal wall.

What concept does this question test?

It tests Thorax and diaphragm: phrenic nerve in Anatomy. The skin over the shoulder tip is supplied by C3 and C4 through the supraclavicular nerves, so diaphragmatic irritation is felt there. The peripheral diaphragm is supplied by the lower intercostal nerves, whose irritation causes pain in the lower chest or abdominal wall.

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 and diaphragm: 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.