Thorax: cardiac pain pathway: 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: cardiac pain pathway

Sample item

A 58-year-old man with acute myocardial ischaemia feels pain in the chest and along the inner side of the left arm, although the heart itself has no somatic sensory supply. Which anatomical explanation accounts for the arm pain?

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

The answer and the reasoning

C. Cardiac afferents entering at T1 to T4 converge with medial arm somatic afferents

Pain fibres from the heart run with the sympathetic cardiac nerves through the cervical and upper thoracic ganglia to enter the cord at roughly T1 to T4. Second-order neurons also receive somatic input from the same segments, including the medial arm (T1 and T2, through the intercostobrachial nerve), so the brain interprets the visceral pain as arising from that skin.

Option by option

  • A. Cardiac afferents enter at T10 to L1 and refer the pain to the epigastrium

    T10 to L1 segments relate to the lower abdomen and not to the heart.

  • B. Cardiac afferents travel with the phrenic nerve to the C3 to C5 cord segments

    C3 to C5 phrenic referral produces shoulder tip pain from diaphragmatic or pericardial irritation, not the medial arm.

  • C. Cardiac afferents entering at T1 to T4 converge with medial arm somatic afferents (correct)

    Correct. Convergence of cardiac and somatic afferents at T1 to T4 produces referred pain in the medial arm.

  • D. Vagal afferents relay in the brainstem and project to the upper limb skin

    Vagal afferents mainly carry reflex information such as cardiac baroreceptor input and do not account for referral to the arm.

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, Cardiac afferents entering at T1 to T4 converge with medial arm somatic afferents. Pain fibres from the heart run with the sympathetic cardiac nerves through the cervical and upper thoracic ganglia to enter the cord at roughly T1 to T4.

Why is "Cardiac afferents enter at T10 to L1 and refer the pain to the epigas…" not the answer?

T10 to L1 segments relate to the lower abdomen and not to the heart.

Why is "Cardiac afferents travel with the phrenic nerve to the C3 to C5 cord…" not the answer?

C3 to C5 phrenic referral produces shoulder tip pain from diaphragmatic or pericardial irritation, not the medial arm.

Why is "Vagal afferents relay in the brainstem and project to the upper limb…" not the answer?

Vagal afferents mainly carry reflex information such as cardiac baroreceptor input and do not account for referral to the arm.

What concept does this question test?

It tests Thorax: cardiac pain pathway in Anatomy. Second-order neurons also receive somatic input from the same segments, including the medial arm (T1 and T2, through the intercostobrachial nerve), so the brain interprets the visceral pain as arising from that skin.

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 Thorax: cardiac pain pathway?

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.