A 48-year-old woman notices a change in voice immediately after total thyroidectomy for a benign multinodular goitre. She cannot produce high-pitched sounds and her voice fatigues easily, though she is not breathless. Laryngoscopy shows normal vocal cord mobility. Which nerve is most likely injured?

• A Recurrent laryngeal nerve
• B Ansa cervicalis
• C Internal branch of the superior laryngeal nerve
• D External branch of the superior laryngeal nerve ✓

Explanation

The external branch of the superior laryngeal nerve (EBSLN) innervates the cricothyroid muscle, which tenses the vocal cords and is essential for high-pitched phonation. Injury causes voice fatigue and loss of high pitch with normal cord mobility on laryngoscopy. The recurrent laryngeal nerve injury would cause cord paralysis. The internal branch provides supraglottic sensation, and ansa cervicalis innervates infrahyoid muscles.

Reference: Bailey and Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.