Intrinsic Muscles of the Laryngeal System Flashcards
Origin of Conus Elasticus
superior rim of the cricoid
Insertion of Conus Elasticus
edges of the vocal ligament and the arytenoids
Membranous Glottis
3/5th of anterior portion
Cartilaginous Glottis
remainder posterior 2/5ths
Vestibule
Supraglottal region that begins inferiorly just above the ventricular folds to the opening of the larynx
Subglottal Atrium
from vocal folds (just below glottis) and below
-lined with cilia to help remove mucus accumulations and foreign matter from respiratory tract
Valleculae
space between epiglottis and root of tongue
Ventricle (Laryngeal Ventricle)
small supraglottis region between vocal folds and ventricular folds
Ventricular Folds
aka False folds
- soft and flaccid indentations
- incapable of becoming tense
- under normal circumstances do not vibrate during phonation
- false glottis is larger than actual glottis
Intrinsic muscles
muscles that have both attachments inside the larynx
Cricothyroid muscles
bilateral pairs that span superiolaterally between the cricoid and thyroid cartilages
- pars recta
- pars oblique
Pars Recta origin
arch of the cricoid cartilages
Pars Recta Insert
inferior border of the thyroid lamina
Pars Recta Action
rocks thyroid anteriorly and inferiorly (forward and down), closer to cricoid
Pars Oblique Origin
arch of cricoid cartilage
PArs Oblique Insert
inferior horn of the thyroid
Pars Oblique Action
pulls thyroid anteriorly
Cricothyroid muscles overall action
rock cricoid and thyroid closer to the other
lengthens VFs, thus increasing tension and decreasing mass, thus affecting pitch
increase length and tension of VFs
Posterior Cricoarytenoid (PCA)
large fan shaped muscle located on the dorsal surface of the cricoid
Origin of Conus Elasticus
superior rim of the cricoid
PCA origin
lateral/posterior half of cricoid lamina
PCA insert
superior surface of muscular process of arytenoid
PCA action
abducts the arytenoids, thus abducting the VFs
*only Vf abductor of larynx
Lateral Cricoarytenoid (LCA)
small muscle, yet very important for vocalization
LCA origin
superior rim on anterior/lateral portion of the cricoid cartilage
LCA insert
posterosuperior (back and up) course to the lateral half of the muscular process of the arytenoid cartilage
LCA action
adduction, or bringing the VFs together
antagonist to PCA
involved in medial compression-the force exerted to close VFs
Interarytenoids (IA)
between the arytenoids
included oblique arytenoid and the transverse arytenoid muscles
Oblique (Inter)Arytenoid (OIA) origin
medial half of the muscular process (base) of arytenoid cartilages
OIA insert
courses superomedial, cross midline and insert into the contralateral arytenoid on the apex
OIA action
adduct VFs
agonist to LCA
Transverse (Inter)Arytenoid (TIA) origin
posterior surface of arytenoid cartilage
TIA insert
attaches to dorsomedial surface of opposite arytenoid cartilage
TIA action
powerful VF adductor, draw apexes together
Thryoarytenoid (TA)
extends anterior-posteriorly (front to back) to make up the muscle mass of the vocal folds (true vocal folds)
composed of medial and lateral parts
TA origin
deep surface of thyroid lamina, near angle
TA insert
vocal process of arytenoids
TA action
decreases distance between the thyroid and arytenoid cartilages, thus shortening VFs
- acts as a regulator of longitudinal tension
- when unopposed by other mm’s, TA relaxes VFs
- when opposed by other mm’s, increase in tension of VFs
Cover of VFs
epithelium and superficial layer of lamina propria
Transition of VFs
immediate and deep layers of lamina propria
also make up vocal ligament
Body of VFs
throarytenoid muscles
Extrinsic Laryngeal Muscles (strap muscles)
muscles that have 1 attachment to structures outside of the larynx
-primarily responsible for the support of the larynx and for fixing it in position
Infrahyoids
point of attachment outside of larynx is below hyoid bone
when mm’s contract, they pull the larynx down
origin is inferior to insertion
suprahyoids
attachment outside larynx is above hyoid bone
when mm’s contract, pull larynx up
origin is superior to insertion
