A 32-year-old professional singer undergoes total thyroidectomy for a multinodular goitre. Postoperatively her speaking voice is normal, but she cannot sing high notes and her voice tires quickly on prolonged phonation. Laryngoscopy shows normal vocal cord mobility bilaterally. Which nerve injury explains these findings?

• A Bilateral recurrent laryngeal nerve palsy
• B Unilateral recurrent laryngeal nerve palsy
• C Injury to the internal branch of the superior laryngeal nerve
• D Injury to the external branch of the superior laryngeal nerve ✓

Explanation

The external branch of the superior laryngeal nerve supplies cricothyroid, the muscle that tenses the vocal cords and produces high pitch. Injury leaves conversational voice intact but causes loss of high register and rapid voice fatigue, the classic complaint in singers. The internal branch is purely sensory to the supraglottic larynx. Recurrent laryngeal palsy causes hoarseness with impaired cord movement, which laryngoscopy excludes here.

Reference: Bailey and Love's Short Practice of Surgery, 28th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.