Roots
The five roots are the ventral rami originating from spinal nerve levels C5–T1.
The roots course between the anterior and middle scalene muscles, along with the subclavian artery.
Arising from the roots are branches to the longus colli and scalene muscles
The dorsal scapular nerve (C5) innervates the rhomboid and levator scapular muscles.
The long thoracic nerve (C5–C7) innervates the serratus anterior muscle.
https://youtu.be/Zb6UiDauQYY
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