UNIT 4: Intrinsic and Extrinsic Laryngeal Musculature Flashcards
What are intrinsic laryngeal muscles?
- have origin and insertion on laryngeal cartilages
- control adduction-abduction of VFs
- control tension-relaxation of VFs
what is the glottis?
a variable opening bw the true VFs (horizontal plane)
where does the glottis begin and end
from anterior commissure (at thyroid angle) to posterior commisure (bw arytenoids)
how large is the glottis?
about 20mm in adults
what is the membranous portion of the glottis
approx 3/5 of the length of the total glottis; bw the folds themselves
what is the cartilaginous portion of the glottis
approx 2/5 of the length of the glottis; bw the arytenoid cartilages
what part of the glottis is open/closed when we whisper?
cartilaginous portion open and membranous portion closed
are the interarytenoids intrinsic or extrinsic
intrinsic
what are the two interarytenoid muscles
transverse and oblique
Transverse interarytenoid: O, I, A, INN
O = lateral border of each arytenoid bw the muscular process and apex
I = lateral border of opposite arytenoid
A = medial approximation of arytenoids, closes the glottis (adduction)
Inn = RLN of CN X
Oblique interarytenoid: O, I, A, INN
O= posterior surface of the base of one arytenoid
I= apex of the opposite arytenoid
A= medial approximation (adduction) of the arytenoids
Inn= RLN of CN X
what shape do the transverse and oblique interarytenoids make
an X, they cross over each other
what 3 intrinsic muscles are adductors
transverse interarytenoid
oblique interarytenoid
lateral cricoarytenoid
Lateral cricoarytenoid: O, I, A, INN
O = superior surface of the anterolateral border of the cricoid arch
I = anterior surface of the muscular process of the arytenoids
A= adducts vocal folds by rotating the vocal processes of the arytenoids medially
Inn = RLN of CN X
lateral cricoaytenoid is _____ and is located _____ to the thyroid cartilage
paired
deep
if we just use the lateral cricoarytenoid it will close the ______ glottis, which will produce a ______
membranous
whisper
is the lateral cricoarytenoid intrinsic or extrinsic
intrinsic
is the posterior cricoarytenoid intrinsic or extrinsic
intrinsic
posterior cricoarytenoid: O, I, A, Inn
O = posterior quadrate lamina of the cricoid
I = posterior surface of the muscular process of the arytenoid
A= abducts the vocal folds and opens the glottis by rotating arytenoids laterally
Inn = RLN of X
which intrinsic muscle is an abductor
posterior cricoarytenoid (PCA)
posterior cricoarytenoid is ___ shaped, on the _____ surface of the _____, and it is _____
fan shaped, posterior, cricoid, paired
cricothyroid muscle is ______ shaped muscle located bw _____ and _____ cartilages, there are two divisions: _____ and ______
fan
cricoid and thyroid
pars oblique
pars recta
cricothyroid: O, I, A, Inn
O = cricoid arch, anterolateral region
I = inferior border of the lamina and inferior cornu of the thyroid
A = decreases the distance bw thyroid and cricoid; pulls thyroid anteriorly, lengthening and thinning the VFS, inc longitudinal tension and pitch
inn = external branch of the superior laryngeal nerve (eSLN) of CN X
why is the innervation of the cricothyroid special? what aspect of phonation would be affected by damage to this innervation?
ONLY ONE INNERVATED BY SUPERIOR LARYNGEAL NERVE OF CN X
If a patient cannot change pitch it may be due to cricothyroid or superior laryngeal nerve
if the RLN is damaged we would expect a patient to have issues with…
closing their airway
thyroarytenoud may function to increase or decrease _________ (depending on co-activation of other muscles)
fundamental frequency
what are the two portions of the thyroarytenoid?
thyrovocalis
thyromuscularis
thyrovocalis is the ______ portion of the thyroarytenoid
most medial
thyromuscularis is the _____ portion of the thyroarytenoid
most lateral