Aortic coarctation: collateral circulation: 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 · Aortic coarctation: collateral circulation

Sample item

A 14-year-old boy has arm hypertension, weak femoral pulses and a chest radiograph showing notching of the inferior margins of the 3rd to 8th ribs. Which collateral pathway explains the rib notching?

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

The answer and the reasoning

B. Subclavian artery, internal thoracic artery, anterior intercostal arteries, then posterior intercostal arteries running backwards to the descending aorta

In postductal coarctation, blood bypasses the narrowing through the subclavian and internal thoracic arteries into the anterior intercostal arteries. It then flows backwards in the posterior intercostal arteries into the descending aorta. The enlarged, tortuous arteries erode the costal grooves on the lower border of the ribs, and the first two spaces are spared because those arteries arise from the supreme intercostal artery.

Option by option

  • A. Vertebral arteries to the anterior spinal artery, whose dilation erodes the ribs

    The anterior spinal artery lies within the vertebral canal, not in the costal grooves.

  • B. Subclavian artery, internal thoracic artery, anterior intercostal arteries, then posterior intercostal arteries running backwards to the descending aorta (correct)

    Correct. Retrograde flow through enlarged posterior intercostal arteries produces notching of the 3rd to 8th ribs.

  • C. Superior and inferior epigastric arteries bypassing the coarctation to the external iliac artery

    The epigastric route is a recognised collateral but does not lie in the costal grooves.

  • D. Bronchial arteries to the oesophageal arteries and then the descending aorta

    The bronchial and oesophageal arteries are small and do not lie in the costal grooves.

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 B, Subclavian artery, internal thoracic artery, anterior intercostal arteries, then posterior intercostal arteries running backwards to the descending aorta. In postductal coarctation, blood bypasses the narrowing through the subclavian and internal thoracic arteries into the anterior intercostal arteries.

Why is "Vertebral arteries to the anterior spinal artery, whose dilation erod…" not the answer?

The anterior spinal artery lies within the vertebral canal, not in the costal grooves.

Why is "Superior and inferior epigastric arteries bypassing the coarctation t…" not the answer?

The epigastric route is a recognised collateral but does not lie in the costal grooves.

Why is "Bronchial arteries to the oesophageal arteries and then the descendin…" not the answer?

The bronchial and oesophageal arteries are small and do not lie in the costal grooves.

What concept does this question test?

It tests Aortic coarctation: collateral circulation in Anatomy. It then flows backwards in the posterior intercostal arteries into the descending aorta. The enlarged, tortuous arteries erode the costal grooves on the lower border of the ribs, and the first two spaces are spared because those arteries arise from the supreme intercostal artery.

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 Aortic coarctation: collateral circulation?

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.