Comprehension Questions

[1] Which of the following muscles is most important to allow air movement through the larynx?
A. Posterior cricoarytenoids
B. Lateral cricoarytenoids
C. Cricothyroid muscle
D. Infrahyoid muscles
[2] A 33-year-old woman underwent partial thyroidectomy for hyperthyroidism in which the thyroid failed to take up radioactive iodine. She is noted to have some hoarseness of voice 1 month later. Which of the following is the most likely explanation?
A. Endotracheal tube trauma to the vocal cords
B. Injury to the cricoid cartilage
C. Injury to the thyroid cartilage
D. Injury to the recurrent laryngeal nerve
[3] A 15-year-old boy is eating a fish dinner and inadvertently has a bone "caught in his throat." He complains of significant pain above the vocal cords. Which of the following nerves is responsible for carrying the sensation for this pain?
A. Superior laryngeal nerve
B. Recurrent laryngeal nerve
C. Spinal accessory nerve
D. Hypoglossal nerve
[4] A 25-year-old woman underwent thyroid surgery for a thyroid nodule. Two months later, she complains of dryness of skin and muscle spasms. Which of the following is the most likely explanation?
A. Low serum magnesium
B. Low serum calcium
C. Low serum potassium
D. Low serum sodium
E. Low serum glucose
Comprehension Answers


[1] A. The posterior cricoarytenoid muscles are the only muscles that abduct the vocal folds and are necessary to widen the rima glottidis for breathing.
[2] D. Injury to the recurrent laryngeal nerve is common during thyroid surgery and may lead to the inability to tightly adduct the two vocal folds, resulting in hoarseness. In addition, the protective function of the rima glottidis may be lost, and food or liquid that does not go down the esophagus may flow into the trachea and cause a choking response.
[3] A. The laryngeal mucosa above the vocal cords is innervated by the superior laryngeal nerve, whereas it is innervated below the vocal cords by the recurrent laryngeal nerve.
[4] B. This patient likely has hypocalcemia due to excision of the parathyroid glands.