Brachial plexus: Pancoast syndrome: 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 · Brachial plexus: Pancoast syndrome

Sample item

A 62-year-old heavy smoker has pain along the medial side of the arm and forearm, wasting of the small muscles of the hand and weak finger abduction and adduction. He also has ptosis, miosis and anhidrosis of the same side of the face. A chest radiograph shows an apical lung mass. Which pair of structures is most directly invaded by the tumour?

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

The answer and the reasoning

A. The T1 root or lower trunk of the brachial plexus and the stellate (cervicothoracic) ganglion

An apical (Pancoast) tumour grows over the thoracic inlet and invades the lowest roots and trunk of the plexus, producing C8 and T1 pain and intrinsic hand muscle wasting. The cervicothoracic sympathetic chain lies just in front of the neck of the first rib, so Horner syndrome accompanies the plexus lesion. Upper trunk lesions cause shoulder abduction weakness instead.

Option by option

  • A. The T1 root or lower trunk of the brachial plexus and the stellate (cervicothoracic) ganglion (correct)

    The lower trunk carries C8 and T1 fibres to the ulnar side of the hand, and the stellate ganglion carries sympathetic fibres to the head.

  • B. The C5 and C6 roots (upper trunk) and the phrenic nerve

    The upper trunk supplies shoulder abduction and elbow flexion and would not cause intrinsic hand wasting; phrenic injury gives diaphragmatic paralysis.

  • C. The posterior cord of the brachial plexus and the recurrent laryngeal nerve

    The posterior cord gives radial and axillary nerves, which do not explain medial forearm pain, and recurrent laryngeal injury gives hoarseness.

  • D. The lateral cord of the brachial plexus and the superior cervical ganglion

    The lateral cord supplies the biceps and part of the median nerve, so hand intrinsic wasting and medial arm pain would not be explained.

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 A, The T1 root or lower trunk of the brachial plexus and the stellate (cervicothoracic) ganglion. An apical (Pancoast) tumour grows over the thoracic inlet and invades the lowest roots and trunk of the plexus, producing C8 and T1 pain and intrinsic hand muscle wasting.

Why is "The C5 and C6 roots (upper trunk) and the phrenic nerve" not the answer?

The upper trunk supplies shoulder abduction and elbow flexion and would not cause intrinsic hand wasting; phrenic injury gives diaphragmatic paralysis.

Why is "The posterior cord of the brachial plexus and the recurrent laryngeal…" not the answer?

The posterior cord gives radial and axillary nerves, which do not explain medial forearm pain, and recurrent laryngeal injury gives hoarseness.

Why is "The lateral cord of the brachial plexus and the superior cervical gan…" not the answer?

The lateral cord supplies the biceps and part of the median nerve, so hand intrinsic wasting and medial arm pain would not be explained.

What concept does this question test?

It tests Brachial plexus: Pancoast syndrome in Anatomy. The cervicothoracic sympathetic chain lies just in front of the neck of the first rib, so Horner syndrome accompanies the plexus lesion. Upper trunk lesions cause shoulder abduction weakness instead.

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 Brachial plexus: Pancoast syndrome?

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.