Anatomy of Intrinsic Laryngeal Muscles

Question 1

4 functions and how they affect voice

Answer 1

Tension - raise pitch

Relaxation - lower pitch

Abduction - raise volume

Adduction - lower volume

Question 2

Muscles that tense the vocal cords

Effect on voice

Answer 2

Cricothyroid muscles

Nods the thyroid cartilage down, tensing the vocal cords and raising the pitch of the voice

Question 3

Muscles that relax the vocal cords

Effect on voice

Answer 3

Thyroarytenoid muscles

Cause the pitch to lower

Question 4

Muscles that Abduct the vocal cords

Effect on voice

Answer 4

Posterior cricoarytenoid muscles

Make the voice louder

Question 5

Muscles that adduct the vocal cords

Effect on voice

Answer 5

Lateral cricoarytenoids

AND

Arytenoids (oblique and transverse)

Lowers volume of voice

Question 6

Which intrinsic laryngeal muscles contract during forced expiration?

Answer 6

Posterior cricoarytenoids - need to abduct vocal cords

Question 7

Which intrinsic laryngeal muscles contract during phonation?

Answer 7

Arytenoids, also assisted by lateral cricoarytenoids

Question 8

Which intrinsic laryngeal muscles contract during whispering

Answer 8

Lateral cricoarytenoids only

Question 9

Nerve supplying all intrinsic laryngeal muscles

Answer 9

CN X

Question 10

Describe the path of the vagus nerve as it supplies the larynx

Answer 10

Gives off superior larygeal branch, which splits into internal (superior) and external (inferior)

travels down and gives off a branch that loops under the arch of the aorta - Recurrent Laryngeal (left)

RL nerve becomes inferior laryngeal at the level of the cricoid

Question 11

Which branches of the vagus nerve supply each of the intrinsic laryngeal muscles?

Answer 11

Inferior laryngeal nerve

• Thyroarytenoid muscles
• Cricoarytenoid muscles (both posterior and lateral)
• Arytenoid muscles (both transverse and oblique bands)

External laryngeal nerve

• Cricothyroid muscles