During thyroidectomy, the external branch of the superior laryngeal nerve (EBSLN) is at risk of injury. Injury to this nerve produces which clinical deficit?
- A Inability to produce high-pitched sounds ✓
- B Loss of cough reflex
- C Hoarseness of voice
- D Stridor on exertion
Correct answer: A. Inability to produce high-pitched sounds
Explanation
The external branch of the superior laryngeal nerve innervates the cricothyroid muscle, which tenses the vocal cords. Injury causes inability to produce high-pitched sounds and voice fatigue. Hoarseness is caused by recurrent laryngeal nerve injury. Loss of cough reflex is due to internal branch of superior laryngeal nerve injury. Stridor suggests bilateral RLN injury.
Reference: Bailey and Love's Short Practice of Surgery, 27th ed.
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