The long thoracic nerve (nerve of Bell) is formed from which roots?
- A C5, C6, C7 ✓
- B C5, C6
- C C6, C7, C8
- D C7, C8, T1
Correct answer: A. C5, C6, C7
Explanation
The long thoracic nerve arises from the roots of C5, C6, and C7 before they join to form the brachial plexus proper. It descends posterior to the brachial plexus along the lateral chest wall to innervate serratus anterior. Injury (e.g., from radical mastectomy, carrying heavy loads, or direct trauma) causes paralysis of serratus anterior, resulting in winging of the scapula (medial border of the scapula becomes prominent when the arm is pushed against a wall).
Reference: BD Chaurasia's Human Anatomy, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.