The long thoracic nerve (nerve to serratus anterior) arises from which roots of the brachial plexus?

• A C5, C6, C7 ✓
• B C5, C6 only
• C C6, C7, C8
• D C4, C5, C6

Explanation

The long thoracic nerve (nerve of Bell) arises from the ventral rami of C5, C6, and C7 directly (before the formation of trunks), descends along the lateral thoracic wall to innervate the serratus anterior. Its long, superficial course makes it vulnerable to direct trauma, iatrogenic injury (during mastectomy, thoracotomy, port placement), or prolonged stretch (carrying heavy loads on the shoulder). Its paralysis causes medial winging of the scapula — inability to protract the scapula — prominent on pushing against a wall.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.