Injury to what nerve causes winged scapula?

• A. Dorsal scapular nerve
• B. Long thoracic nerve
• C. Axillary nerve
• D. Spinal accessory nerve

Answer: (B)

Winged scapula reflects failure of serratus anterior to keep the scapula pressed against the thoracic wall and to rotate it upward for full arm elevation. The serratus anterior is innervated by the long thoracic nerve, which arises from C5–C7 and runs along the lateral chest wall. When this nerve is injured, serratus anterior can’t hold the medial border of the scapula tightly to the rib cage, so the medial edge protrudes, especially when the patient pushes against a wall or raises the arm.

Other nerves don’t produce the classic winging pattern. Dorsal scapular nerve affects rhomboids and levator scapulae and mainly alters scapular retraction and stabilization rather than producing the prominent medial winging. Axillary nerve injury affects the deltoid (and teres minor), leading to weakness of arm abduction and shoulder contour changes, not the winged appearance. Spinal accessory nerve weakness involves the trapezius, causing a drooped shoulder and trouble shrugging, again not the characteristic winging.