Upper limb and brachial plexus: plexus architecture: 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.

Try it

Anatomy · Upper limb and brachial plexus: plexus architecture

Sample item

During a supraclavicular exploration behind the clavicle, a surgeon identifies the posterior divisions of the upper, middle and lower trunks of the brachial plexus. These unite to form which structure?

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

The answer and the reasoning

B. Posterior cord

Each trunk divides into an anterior and a posterior division behind the clavicle. All three posterior divisions (C5 to T1) join to form the posterior cord, which gives the axillary and radial nerves. The anterior divisions of the upper and middle trunks form the lateral cord, and that of the lower trunk continues as the medial cord.

Option by option

  • A. Lateral cord

    The lateral cord is formed by anterior divisions of the upper and middle trunks.

  • B. Posterior cord (correct)

    Correct. The three posterior divisions fuse to form the posterior cord.

  • C. Upper trunk

    The upper trunk is a proximal structure formed from the C5 and C6 roots before the divisions.

  • D. Medial cord

    The medial cord is the continuation of the anterior division of the lower trunk.

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 B, Posterior cord. Each trunk divides into an anterior and a posterior division behind the clavicle.

Why is "Lateral cord" not the answer?

The lateral cord is formed by anterior divisions of the upper and middle trunks.

Why is "Upper trunk" not the answer?

The upper trunk is a proximal structure formed from the C5 and C6 roots before the divisions.

Why is "Medial cord" not the answer?

The medial cord is the continuation of the anterior division of the lower trunk.

What concept does this question test?

It tests Upper limb and brachial plexus: plexus architecture in Anatomy. All three posterior divisions (C5 to T1) join to form the posterior cord, which gives the axillary and radial nerves. The anterior divisions of the upper and middle trunks form the lateral cord, and that of the lower trunk continues as the medial cord.

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 Upper limb and brachial plexus: plexus architecture?

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.