Axilla: thoracodorsal nerve: 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 · Axilla: thoracodorsal nerve

Sample item

During an axillary lymph node dissection, a surgeon preserves the nerve that runs along the posterior wall of the axilla with the subscapular vessels. If it were divided, which function would be weakened?

AAdduction and extension of the abducted arm, as in climbingBProtraction of the scapula against a wallCAbduction of the arm from 15 to 90 degreesDElevation of the shoulder in a shrug

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

The answer and the reasoning

A. Adduction and extension of the abducted arm, as in climbing

The thoracodorsal nerve (C6 to C8, middle subscapular nerve) arises from the posterior cord and supplies latissimus dorsi. It travels down the posterior axillary wall with the subscapular artery and can be injured in axillary clearance. Loss weakens adduction, medial rotation and extension of the arm, noticeable in climbing and pull-ups.

Option by option

A. Adduction and extension of the abducted arm, as in climbing (correct)
Correct. Latissimus dorsi, supplied by the thoracodorsal nerve, powers these movements.
B. Protraction of the scapula against a wall
Protraction of the scapula is by serratus anterior, supplied by the long thoracic nerve.
C. Abduction of the arm from 15 to 90 degrees
Abduction from 15 to 90 degrees is by deltoid, supplied by the axillary nerve.
D. Elevation of the shoulder in a shrug
Shrugging is by trapezius, supplied by the spinal accessory 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.

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is A, Adduction and extension of the abducted arm, as in climbing. The thoracodorsal nerve (C6 to C8, middle subscapular nerve) arises from the posterior cord and supplies latissimus dorsi.

Why is "Protraction of the scapula against a wall" not the answer?

Protraction of the scapula is by serratus anterior, supplied by the long thoracic nerve.

Why is "Abduction of the arm from 15 to 90 degrees" not the answer?

Abduction from 15 to 90 degrees is by deltoid, supplied by the axillary nerve.

Why is "Elevation of the shoulder in a shrug" not the answer?

Shrugging is by trapezius, supplied by the spinal accessory nerve.

What concept does this question test?

It tests Axilla: thoracodorsal nerve in Anatomy. It travels down the posterior axillary wall with the subscapular artery and can be injured in axillary clearance. Loss weakens adduction, medial rotation and extension of the arm, noticeable in climbing and pull-ups.

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 Axilla: thoracodorsal nerve?

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.