Regional anaesthesia: interscalene block: practice question

A Anaesthesia 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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Anaesthesia · Regional anaesthesia: interscalene block

Sample item

Interscalene block commonly results in ipsilateral diaphragmatic paralysis. Which nerve is blocked?

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

The answer and the reasoning

A. Phrenic nerve

The phrenic nerve (C3 to C5) lies on the anterior scalene muscle and is blocked by spread of local anaesthetic in nearly all patients. It is avoided in severe respiratory disease. The lower trunk (C8, T1) is often spared.

Option by option

  • A. Phrenic nerve (correct)

    Correct. Phrenic palsy follows interscalene block.

  • B. Recurrent laryngeal nerve only

    The recurrent laryngeal nerve causes hoarseness.

  • C. Vagus nerve

    The vagus is not the cause of hemidiaphragm paralysis.

  • D. Long thoracic nerve

    The long thoracic nerve supplies serratus anterior.

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 Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is A, Phrenic nerve. The phrenic nerve (C3 to C5) lies on the anterior scalene muscle and is blocked by spread of local anaesthetic in nearly all patients.

Why is "Recurrent laryngeal nerve only" not the answer?

The recurrent laryngeal nerve causes hoarseness.

Why is "Vagus nerve" not the answer?

The vagus is not the cause of hemidiaphragm paralysis.

Why is "Long thoracic nerve" not the answer?

The long thoracic nerve supplies serratus anterior.

What concept does this question test?

It tests Regional anaesthesia: interscalene block in Anaesthesia. It is avoided in severe respiratory disease. The lower trunk (C8, T1) is often spared.

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 Regional anaesthesia: interscalene block?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia 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.