Thorax: venous drainage of the thymus: 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: venous drainage of the thymus

Sample item

During thymectomy through a median sternotomy for myasthenia gravis, a surgeon ligates the thymic veins as they leave the gland. Which vessel do they chiefly enter?

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

The answer and the reasoning

C. Left brachiocephalic vein

The thymus lies in the anterior mediastinum in front of the left brachiocephalic vein. Its veins drain mainly into that vein, with smaller tributaries to the internal thoracic and inferior thyroid veins. Injury to the left brachiocephalic vein is a recognised hazard of the dissection.

Option by option

  • A. Azygos vein

    The azygos vein is in the posterior mediastinum and does not receive thymic blood.

  • B. Superior vena cava

    The thymic veins do not usually enter the superior vena cava directly.

  • C. Left brachiocephalic vein (correct)

    Correct. The thymic veins pass into the left brachiocephalic vein behind the gland.

  • D. Right brachiocephalic vein

    The right brachiocephalic vein lies away from the thymus and is not its usual outlet.

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, Left brachiocephalic vein. The thymus lies in the anterior mediastinum in front of the left brachiocephalic vein.

Why is "Azygos vein" not the answer?

The azygos vein is in the posterior mediastinum and does not receive thymic blood.

Why is "Superior vena cava" not the answer?

The thymic veins do not usually enter the superior vena cava directly.

Why is "Right brachiocephalic vein" not the answer?

The right brachiocephalic vein lies away from the thymus and is not its usual outlet.

What concept does this question test?

It tests Thorax: venous drainage of the thymus in Anatomy. Its veins drain mainly into that vein, with smaller tributaries to the internal thoracic and inferior thyroid veins. Injury to the left brachiocephalic vein is a recognised hazard of the dissection.

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: venous drainage of the thymus?

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.