Intrinsic Laryngeal Muscles

Question 1

Origin: posterior cricoid lamina
Insertion: posterior aspect of the muscular process of the arytenoid
Direction: runs obliquely up
Function: Pulls the muscular process of the arytenoid posteriorly to rock arytenoid laterally -> abducts VFs
Motor Supply: CN X (Vagus), recurrent layrngeal nerve branch

Answer 1

Posterior cricoarytenoid (PCA)

Question 2

Origin: superolateral surface of cricoid cartilage
Insertion: muscular processes of the arytenoid
Function: rotates the muscular process of the arytenoids anteriorly, rocking the vocal process medially and inferiorly -> adduction of the membranous vocal folds
Motor supply: CN X (Vagus), RLN: recurrent laryngeal nerve

Answer 2

Lateral cricoarytenoid (LCA)

Question 3

Origin: lateral margin of posterior arytenoid
Insertion: lateral margin of opposite posterior arytenoid
Function: pulls two arytenoids closer to approximate the cartilaginous VFs (adduction of posterior glottis)
Motor Supply: CN X (Recurrent laryngeal nerve)

Answer 3

Transverse Fibers - Interarytenoid Muscles

Question 4

Origin: posterior base of muscular process of arytenoid
Insertion: apex of opposite arytenoid
Function: pulls two arytenoids closer to approximate the cartilaginous VFs (adduction of posterior glottis)
Motor Supply: CN X (Recurrent laryngeal nerve)

Answer 4

Oblique Fibers - Interarytenoid Muscules

Question 5

What two muscles contractions cause voicing?

Answer 5

Lateral cricoarytenoid muscle and interarytenoids (transverse and oblique)

Question 6

Origin: inner surface of anterior thyroid cartilage
Insertion: arytenoid (1. lateral surface of vocal process, 2. base and muscular process)
Motor supply: RLN

Answer 6

Thyroarytenoid (TA) - thyrovocalis and thyromuscularis

Question 7

Origin: anterolateral surfaces of arch of cricoid cartilage
Insertion: lateral inferior border of the thyroid lamina cartilage and anterior surface of the inferior horn
Two parts: pars recta, pars oblique
Action: Upon contraction, this pulls the thyroid and cricoid together, lengthening and tensing the VFs
Motor Supply: CN X, external branch of superior laryngeal nerve

Answer 7

Cricothyroid (CT)

Question 8

The cricothyroid muscle:
a) relaxes the vocal folds when it rocks the thyroid forwardly
b) increases the distance between thyroid and cricoid cartilages anteriorly
c) decreases the distance between thyroid and cricoid cartilages anteriorly

Answer 8

C

Question 9

Only one of the following muscles does not share a common feature. What is it?
a) lateral cricoarytenoid muscle (LCA)
b) Oblique interarytenoids muscle (IA)
c) thyroarytenoid muscle (TA)
d) cricothyroid muscle (CT)
e) Mylohyoid muscle

Answer 9

E

Question 10

Which is incorrect?
a) transverse arytenoids muscle pulls arytenoid cartilages together medially
b) origin of ‘posterior cricoarytenoid (PCA): posterior cricoid lamina
c) PCA is an adductor
d) thyrovocalis is a tensor

Answer 10

C - PCA is an ABductor

Question 11

What muscle rocks vocal process medially and inferiorly causing adduction of membranous vocal fold?

Answer 11

Lateral cricoarytenoid muscle