Long thoracic nerve (nerve of Bell) palsy causes winging of the scapula because it denervates the serratus anterior. In which direction does the inferior angle of the scapula deviate when winging is present?

• A Laterally away from the midline
• B Superiorly toward the acromion
• C Inferolaterally with rotation
• D Medially and posteriorly toward the midline ✓

Explanation

Serratus anterior normally protracts and rotates the scapula during arm elevation, holding the medial border flat against the thorax. When paralysed, the trapezius pulls the inferior angle medially toward the spine, producing medial winging. This is exacerbated when the patient pushes against a wall with arms forward. Spinal accessory nerve (trapezius) injury produces lateral winging with the superior angle tilting medially because the trapezius cannot counter the pull of serratus — the distinction is clinically important.

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

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Written and medically reviewed by the StethoPrep medical team.