A professional singer undergoes total thyroidectomy. Voice is strong in conversation but she cannot reach her previous high notes. Indirect laryngoscopy shows normal vocal cord mobility bilaterally. Which structure was injured?
- A Recurrent laryngeal nerve, left side
- 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. Injury causes loss of high pitch and easy voice fatigue while cord movement on laryngoscopy remains normal, since the cords still abduct and adduct. This nerve runs with the superior thyroid artery, so the preventive step is ligating superior pole vessels individually close to the gland. Internal branch injury causes sensory loss with aspiration risk, not voice change.
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.