A surgeon performing thyroidectomy inadvertently damages the external laryngeal nerve. The MOST specific functional deficit expected is:

• A Hoarseness and inability to abduct the vocal cords
• B Loss of high-pitched phonation due to denervation of cricothyroid muscle ✓
• C Bilateral vocal cord palsy causing stridor
• D Loss of sensation below the vocal cords

Explanation

The external laryngeal nerve (a branch of the superior laryngeal nerve from the vagus) is the sole motor supply to the cricothyroid muscle, which is the only intrinsic laryngeal muscle whose motor supply does NOT run through the recurrent laryngeal nerve. The cricothyroid tenses (elongates) the vocal cords, allowing production of high-pitched sounds; its denervation causes subtle hoarseness and inability to increase vocal pitch — critical for singers and public speakers. Vocal cord abduction/adduction is mediated by RLN-supplied muscles; stridor implies bilateral RLN injury.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.