During an axillary node dissection for breast cancer, the long thoracic nerve is inadvertently sectioned. Which specific functional deficit would the surgeon MOST likely observe postoperatively?

• A Winging of the scapula, most prominent on abduction beyond 90 degrees
• B Winging of the scapula, most prominent on pushing forward against resistance ✓
• C Inability to flex the elbow against resistance
• D Loss of sensation over the medial arm

Explanation

The long thoracic nerve (C5-C7) innervates serratus anterior, which holds the medial border of the scapula against the thoracic wall and rotates the scapula upward. Injury produces medial winging of the scapula, most apparent when the patient pushes against a wall (active forward flexion at 90°). Trapezius palsy (CN XI injury) causes lateral winging of the scapula, prominent during abduction. The long thoracic nerve is at risk in axillary dissection, radical mastectomy, and lateral thoracotomy.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.