Week 29 - Thyroid & Larynx

Question 1

Of the following muscles, which is innervated by a branch of the superior laryngeal nerve?

• a) Posterior cricoarytenoid
• b) Thyroarytenoid
• c) Lateral cricoarytenoid
• d) Cricothyroid
• e) Oblique arytenoid

Answer 1

Of the following muscles, which is innervated by a branch of the superior laryngeal nerve?

• a) Posterior cricoarytenoid
• b) Thyroarytenoid
• c) Lateral cricoarytenoid
• d) Cricothyroid
• e) Oblique arytenoid

Question 2

What is the function of the posterior cricoarytenoid muscles?

Innervation?

Answer 2

The posterior cricoarytenoid muscles are the only muscles to open the vocal cords. By rotating the arytenoid cartilages laterally, these muscles abduct the vocal cords and thereby open the rima glottidis. Their action opposes the lateral cricoarytenoid muscles.

The posterior cricoarytenoid muscles are innervated by the Inferior laryngeal nerve (of recurrent laryngeal nerve (CN X - vagus).

Question 3

What is the innervation of the posterior cricoarytenoid muscles?

Answer 3

The posterior cricoarytenoid muscles are innervated by the Inferior laryngeal nerve (of recurrent laryngeal nerve (CN X - vagus).

Question 4

The superior thyroid artery is a branch of the:

• a) Subclavian artery
• b) External carotid artery
• c) Thyrocervical trunk
• d) Internal carotid artery
• e) Mandibular artery

Answer 4

Question 5

List three structures that may be compressed by a large thyroid mass.

Answer 5

This mass will compress the trachea (windpipe) and esophagus = compressive symptoms - cough & dysphagia

BVs = Internal carotid artery, internal jugular vein