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
thyrovocalis: O, I, A, Inn
O = inferior border of the thyroid angle (inner surface)
I = vocal processes of arytenoids
A = controls tension of VFs w the cricothyroid muscle
Inn = RLN of CN X
Thyromuscularis: O, I, A, Inn
O = inferior border of the thyroid angle (inner surface)
I = muscular processes of arytenoids
A = lateral fibres participate in adduction (rotate); medial fibers shorten/relax VFs
Inn= RLN of CN X
what does it mean that the VFs are held in dynamic balance?
combinations of muscles pulling in different directions
intrinsic laryngeal muscles tend to act in _____ and usually in _____ ______
pairs
complex groups
is the aryepiglotticus intrinsic or extrinsic
intrinsic
_____: a few fibres of the _____ ______ course superiorly and anteriorly in the lateral sides of the aryepiglottic folds
aryepiglotticus
oblique interarytenoids
aryepiglotticus: O, I, A, Inn
O = muscular process of arytenoid
I = lateral margin of epiglottis
A = pull epiglottis downward over laryngeal vestibule
Inn = RLN of X
____: A few fibers of the _____ _____ that course verticially w/i the aryepiglottic folds
thyroepiglotticus
thyroarytenoid muscles
thyroepiglotticus: O, I, A, Inn
O = inferior border of thyroid angle
I= lateral margin of epiglottis and aryepiglottic folds
A = aids in pulling epiglottis downward
Inn = RLN of X
is thyroepiglotticus intrinsic or extrinsic
intrinsic
unilateral vocal fold paralysis is
- paralyzed fold will not move or vibrate; mobile fold may compensate
what symptoms does unilateral vocal fold paralysis cause?
breathy or hoarse voice, limited pitch and loudness; could affect swallowing safety
bilateral vocal fold paralysis causes …. and has what symptom?
both folds sit in paramedian position (not open/not closed)
breathing and swallowing issue more noticeable, may have a trancheostomy tube
what is vocal fold paralysis caused by?
nerve damage
either upper or lower motor neuron
describe paradoxical vocal fold movement - what symps? cause?
vocal folds close when they should be open
inspiration is interrupted by adduction of vocal folds
rough voice quality, difficulty getting enough air in, stridor, lightheadedness
exact cause is unknown (ex. acid reflex, breathing in cold air, inhaled irritants, emotional stress)
what are the two categories of extrinsic muscles of the larynx?
suprahyoid muscles
infrahyoid muscles
the surprahyoid muscles are _________ elevators and _______ depressors, why?
hyoid (laryngeal) elevators OR jaw depressors
some muscles that act as elevators of the larynx act also as depressors of the mandible - when they mandible is fixed these muscles elevate the hyolaryngeal complex - if the hyoid bone is fixed these muscles depress the jaw
the infrahyoid muscles include the _____ depressors and one _____ elevator
hyoid (laryngeal) depressors (strap muscles of the neck) and one laryngeal elevator
what are the 5 suprahyoid muscles (one had 2 within it)
diagastricus = anterior and posterior bellies
stylohyoid
mylohyoid
geniohyoid
hypoglossus
the digastric muscle has two parts and are connected by a …
anterior and posterior bellies
connected via a tendon
anterior belly of the digastric: O, I, A, Inn
O = internal surface of the mandible, near midline
I = intermediate tendon at corpus and greater cornu of hyoid
A = elevates and protrudes hyoid bone
Inn = CN V - trigeminal
posterior belly of the digastric: O, I, A, Inn
O = mastoid process of temporal bone
I = intermediate tendon at corpus/greater cornu of hyoid
A= elevates and retracts hyoid
Inn= CN VII - facial
______ thin sheet that forms the muscular floor of the oral cavity, deep to digastric
mylohyoid
mylohyoid: O, I, A, Inn
O= mylohyoid on internal surface of mandible
I = body of hyoid, midline raphe (w fibres of MH of opposite side)
A= pulls hyoid anteriorly and superiorly
Inn = CN V - trigeminal
_____ narrow, cylindrically shaped muscle, paired, parallel
Geniohyoid
Geniohyoid: O, I, A, Inn
O = Inferior mental spines on the internal surface of the mandible
I = anterior surface of the body of the hyoid
A = elevates and protrudes hyoid bone
Inn = C1 and CN XII -hypoglossal
mylohyoid sandwich?
digastric most superficial under the chin, then mylo, then genio (closest to the tongue)
____ long, thin muscle, approx parallel to posterior belly of digastric
stylohyoid
stylohyoid: O, I, A, Inn
O = styloid process of temporal bone
I = body of the hyoid near the greater cornu (lateral edge)
A = elevates and retracts hyoid bone
Inn = CN VII facial
what are the 5 infrahyoid muscles (one w two parts)?
omohyoid (superior and inferior bellies)
sternohyoid
sternothyroid
thyrohyoid
______: thin, narrow muscle w superior and inferior bellies joined by a central tendon connected by fascia to the clavicle
omohyoid
omohyoid looks like a
hockey stick
omohyoid inferior belly: O, I, A, Inn
O = superior border of scapula
I = intermediate tendon
A = depresses hyoid and larynx
Inn = C1 to C3 ansa cervicallis
omohyoid superior belly: O, I, A, Inn
O = intermediate tendon
I = inferior border of the body of the hyoid
A = depresses hyoid and larynx
Inn = C1 via ansa cervicalis
______: long thin muscle on the anterior surface of the neck
sternohyoid
sternohyoid: O, I, A, Inn
O = posterior surface of the manubrium of the sternum and medial border of the clavicle
I = inferior border of the body of the hyoid
A = lowers the hyoid and larynx
Inn = C1-C3 via ansa cervicalis
____: long, flat muscle on anterior surface of the neck
sternothyroid
sternothyroid: O, I, A, Inn
O = posterior surface of manubrium of sternum and 1st costal cartilage
I = oblique line of the thyroid lamina
A = lowers the thyroid cartilage
Inn = C1-C3 via ansa cervicalis
____: broad, thin muscle on anterior surface of neck
thyrohyoid
thyrohyoid: O, I, A, Inn
O = oblique line of thyroid lamina
I = inferior side of body and greater cornu of hyoid
A= lowers hyoid or elevates thyroid
Inn = spinal nerve C1
Impaired hyolaryngeal elevation
insufficient hyolaryngeal elevation can inc risk of material entering the airway
can be caused neurogenically (ex. stroke, ALS), surgery disrupting suprahyoid musculature, irradiation of the neck
swallowing safety and efficiency is related to a complex pattern of ______ _____ : upward and forward movement of the _____ and ____ pulls the airway out of harms way
sensorimotor events
hyoid
larynx
extrinsic muscles of the larynx can ____ or _____ the hyolaryngeal complex
elevate or depress
thyrohyoid muscle can _____ larynx to a greater extent
elevate
disrupted function of the _____ ______ especially laryngeal elevator muscles can impact swallowing physiology
extrinsic muscles
