laryngeal muscles Flashcards
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 of mms fibers that span superiolaterally between the cricoid and thyroid cartilages
- pars recta (VERTICAL)
- pars oblique (ANGLED)
- pulls thyroid down toward cricoid
- ELONGATES VFs
- major pitch regulator
Pars Recta
VERTICAL mms fibers
- rocks thyroid anteriorly and inferiorly (forward and down), closer to cricoid
- inferior border of thyroid
Pars Oblique
- ANGLED
- inferior horn of thyroid
- pulls thyroid anteriorly
Cricothyroid muscles overall action
- rock cricoid and thyroid closer to the other
- lengthens VFs, thus increasing tension and decreasing mass
- affecting pitchincrease length and tension of VFs
Posterior Cricoarytenoid (PCA)
ONLY VF ABDUCTOR
-large fan shaped muscle located on the dorsal surface of the cricoid
PCA origin
posterior cricoid lamina
PCA insert
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
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
- closes membranous glottis
Interarytenoids (IA)
between the arytenoids
- includes oblique arytenoid and the transverse arytenoid muscles
- closes cartilaginous glottis
OIA action
adduct VFs
agonist (works with) to LCA
-runs across diagonally
TIA action
powerful VF adductor, draw apexes together
-runs laterally
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
Medial TA (vocalis)
inserts to vocal process
Lateral TA (muscularis)
inserts to muscular process
TA action
decreases distance between the thyroid and arytenoid cartilages, thus shortening VFs
- acts as a regulator of longitudinal tension
- PITCH
- 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 propriaalso 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
- 4
- sternohyoid, sternothyroid, omohyoid, thryohyoid
suprahyoids
- attachment outside larynx is above hyoid bone
- when mm’s contract, pull larynx and hyoid up
- origin is superior to insertion
- important for swallowing
- digastric, stylohyoid, mylohyoid (mandible), geniohyoid (tongue)
skeletal muscles
- under voluntary control
- made up of individual mms fibers
- uniquely it can contract
- moves structure to which it attaches
type 1 mms fibers
- aka slow twitch
- slow contraction time, 10-30 twitches/sec
- sustain mms construction for long time w/o fatigue
- marathon runner, smaller, run 4 hours
type 2a mms fibers
- fast twitch
- higher fire rate, 30-70/sec
- fatigue quicker
- large amount of force for brief amount of time
type 2x mms fibers
- twice as fast contraction as type 2a
- relatively fatigue resistant (not as much as type 1)
type 1 and 2 laryngeal mms
- mms involved in glottal closure has a high proportion of type 2 fibers and are FAST contracting (must be fast for like sustenance)
- mms involved in respiration (slow process) and pitch change (lasts over several words and phrases) has more type 1 fibers and are SLOWER contracting
