Chest and cardiac imaging: cervical rib: practice question

A Radiology 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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Radiology · Chest and cardiac imaging: cervical rib

Sample item

A 28-year-old woman has tingling of the ulnar border of the hand and wasting of the thenar muscles. A radiograph shows an extra rib arising from C7. Which structure is compressed against it?

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

The answer and the reasoning

A. Lower trunk of the brachial plexus (C8, T1)

A cervical rib narrows the thoracic outlet and compresses the lower trunk of the brachial plexus and sometimes the subclavian artery, causing ulnar-sided sensory loss and wasting of the small hand muscles. The upper trunk, phrenic nerve and long thoracic nerve are not in the outlet.

Option by option

  • A. Lower trunk of the brachial plexus (C8, T1) (correct)

    Correct. The lower trunk carrying C8 and T1 fibres lies over the first or cervical rib.

  • B. Phrenic nerve

    The phrenic nerve runs on the anterior scalene and is not in the thoracic outlet.

  • C. Long thoracic nerve

    The long thoracic nerve runs on the chest wall and is not compressed by a cervical rib.

  • D. Upper trunk of the brachial plexus (C5, C6)

    The upper trunk lies higher and is not compressed by a cervical rib.

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 Radiology question

What is the answer to this Radiology question?

The best answer is A, Lower trunk of the brachial plexus (C8, T1). A cervical rib narrows the thoracic outlet and compresses the lower trunk of the brachial plexus and sometimes the subclavian artery, causing ulnar-sided sensory loss and wasting of the small hand muscles.

Why is "Phrenic nerve" not the answer?

The phrenic nerve runs on the anterior scalene and is not in the thoracic outlet.

Why is "Long thoracic nerve" not the answer?

The long thoracic nerve runs on the chest wall and is not compressed by a cervical rib.

Why is "Upper trunk of the brachial plexus (C5, C6)" not the answer?

The upper trunk lies higher and is not compressed by a cervical rib.

What concept does this question test?

It tests Chest and cardiac imaging: cervical rib in Radiology. The upper trunk, phrenic nerve and long thoracic nerve are not in the outlet.

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 Chest and cardiac imaging: cervical rib?

Learn signs with the image, and the disease they point to. Then use the flashcards and the other Radiology 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.