Embryology: aortic arch derivatives: 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 · Embryology: aortic arch derivatives

Sample item

During thyroid or mediastinal surgery, which structure on the left forms a landmark around which the recurrent laryngeal nerve hooks, and derives from the sixth pharyngeal arch artery?

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

The answer and the reasoning

A. Ligamentum arteriosum

On the left, the recurrent laryngeal nerve loops beneath the arch of the aorta next to the ligamentum arteriosum, the remnant of the ductus arteriosus (distal part of the left sixth arch). On the right it hooks around the subclavian artery because the right fifth and sixth arch arteries regress.

Option by option

  • A. Ligamentum arteriosum (correct)

    Correct. The ligamentum arteriosum, the remnant of the left ductus arteriosus, lies beside the loop of the left nerve.

  • B. Ductus venosus

    The ductus venosus is a fetal hepatic vessel and has no relation to the recurrent laryngeal nerve.

  • C. Left subclavian artery

    The right recurrent laryngeal nerve loops around the right subclavian artery; the left subclavian is not the landmark.

  • D. Left common carotid artery

    The left common carotid artery runs up the neck and is not looped by the recurrent laryngeal nerve.

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 A, Ligamentum arteriosum. On the left, the recurrent laryngeal nerve loops beneath the arch of the aorta next to the ligamentum arteriosum, the remnant of the ductus arteriosus (distal part of the left sixth arch).

Why is "Ductus venosus" not the answer?

The ductus venosus is a fetal hepatic vessel and has no relation to the recurrent laryngeal nerve.

Why is "Left subclavian artery" not the answer?

The right recurrent laryngeal nerve loops around the right subclavian artery; the left subclavian is not the landmark.

Why is "Left common carotid artery" not the answer?

The left common carotid artery runs up the neck and is not looped by the recurrent laryngeal nerve.

What concept does this question test?

It tests Embryology: aortic arch derivatives in Anatomy. On the right it hooks around the subclavian artery because the right fifth and sixth arch arteries regress.

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 Embryology: aortic arch derivatives?

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.