MUSCLES OF THE LARYNX

Question 1

1. cricothyroid muscle

Answer 1

The cricothyroid muscle stretches and tenses the vocal ligaments, and so is important for the creation of forceful speech. It also has a role in altering the tone of voice (along with the thyroarytenoid muscle), hence its colloquial name ‘singer’s muscle’.

Attachments: Originates from the anterolateral aspect of the cricoid cartilage, and attaches to the inferior margin and inferior horn of the thyroid cartilage.

Actions: Stretches and tenses the vocal ligament.

Innervation: External laryngeal nerve (branch of superior laryngeal). CN X

Question 2

2. thyroarytenoid

Answer 2

The thyroarytenoid muscle acts to relax the vocal ligament, allowing for a softer voice.

Attachments: Originates from the inferoposterior aspect of the angle of the thyroid cartilage, and attaches to the anterolateral part of the arytenoid cartilage.
Actions: Relaxes the vocal ligament.

Innervation: Inferior laryngeal nerve (branch of recurrent laryngeal). from CNX

Question 3

3. posterior crico-arytenoid

Answer 3

The posterior cricoarytenoid muscles are the sole abductors of the vocal folds, and thus the only muscle capable of widening the rima glottidis.

Attachments: Originates from the posterior surface of the cricoid cartilage, and attaches to the vocal process of the arytenoid cartilage.

Actions: Abducts vocal folds.

Innervation: Inferior laryngeal nerve (branch of recurrent laryngeal).

Question 4

4. lateral crico-arytenoid

Answer 4

The lateral cricoarytenoid muscles are the major adductors of the vocal folds. This narrows the rima glottidis, modulating the tone and volume of speech.

Attachments: Originates from the arch of the cricoid cartilage, and attaches to the vocal process of the arytenoid cartilage.

Actions: Adducts the vocal folds.

Innervation: Inferior laryngeal nerve (branch of recurrent laryngeal).

Question 5

5. transverse and oblique arytenoids

Answer 5

The transverse and oblique arytenoids muscles adduct the arytenoid cartilages, closing the posterior portion of the rima glottidis. This narrows the laryngeal inlet.

Attachments: Spans from one arytenoid cartilage to the opposite arytenoid.
Actions: Adducts the arytenoid cartilages.
Innervation: Inferior laryngeal nerve (branch of recurrent laryngeal).

Question 6

6. vocalis

Answer 6

1. The vocalis muscles produce minute adjustments of the vocal ligaments, selectively tensing and relaxing the 
anterior and posterior parts, respectively, during singing.
2.inferior laryngeal nerve 
(terminal part of recurrent 
laryngeal nerve, from 
CN X
3. Relaxes posterior vocal 
ligament while maintaining 
(or increasing) tension of 
anterior part