Study note

Branches associated with the roots of the brachial plexus

THE CONTEXT

Root branches supply serratus anterior, the rhomboids, longus colli and scalene muscles; the passage also describes the phrenic nerve.

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The long thoracic nerve has roots C5–C7 and supplies only serratus anterior, a key muscle for overhead abduction.

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The dorsal scapular nerve supplies rhomboid minor and rhomboid major, which retract the shoulder girdle.

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Branches also supply longus colli and the scalene muscles.

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The main root of the phrenic nerve is from C4.

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The phrenic nerve is the sole motor nerve supplying the thoracoabdominal diaphragm.

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It carries afferent fibres from the mediastinal pleura, fibrous pericardium and part of the parietal peritoneum.

NEETx

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