A 34-year-old woman undergoes total thyroidectomy for multinodular goitre. On postoperative day 1 she speaks in a normal conversational voice but complains that she cannot sing high notes and her voice tires quickly when shouting. Indirect laryngoscopy shows normal vocal cord mobility. Which structure was most likely injured?
- A Recurrent laryngeal nerve
- B External branch of the superior laryngeal nerve ✓
- C Internal branch of the superior laryngeal nerve
- D Hypoglossal nerve
Correct answer: B. External branch of the superior laryngeal nerve
Explanation
The external branch of the superior laryngeal nerve supplies cricothyroid, the tensor of the vocal cord. Its injury preserves cord movement and conversational voice but abolishes high-pitch phonation and causes easy fatiguability of the voice. It is at risk during ligation of the superior thyroid vessels close to the superior pole; ligating them individually on the gland surface avoids injury. The recurrent laryngeal nerve is killed as a distractor because indirect laryngoscopy shows normal cord mobility.
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.