A patient develops hoarseness after thyroid surgery. The surgeon inadvertently ligated the inferior thyroid artery close to the gland. Which nerve is most at risk due to its anatomical relationship with this artery?

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

Explanation

The recurrent laryngeal nerve (RLN) has a variable relationship with the inferior thyroid artery — it may pass anterior, posterior, or between branches of the artery. The RLN is vulnerable when the inferior thyroid artery is ligated near the gland rather than far from it (the safer approach). Damage causes hoarseness (unilateral) or aphonia/stridor (bilateral). The external branch of the superior laryngeal nerve (motor to cricothyroid) is at risk during high ligation of the superior thyroid artery; its injury causes loss of vocal pitch control. The internal branch provides sensation above the vocal cords.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.