Chapter 4 - Anatomy of Phonation Flashcards
biological function of the larynx
-“last safety valve”, it seals the airway by expelling foreign objects (food/liquid)
-produces phonation
-vocal folds permit holding breath (swimming underwater, stabilizes trunk in lifting, childbirth, defecation
penetration vs aspiration
penetration - bolus enters airway but not vocal folds
aspiration - bolus passes through vocal folds
overview of larynx
-it’s a musculo-cartilaginous structure
-located above the 1st tracheal ring
-adjacent to the cervical vertebrae 4-6
structure of the larynx
3 unpaired cartilages
3 paired cartilages
1 bone
various ligaments and mucosa
unpaired cartilages
cricoid, thyroid, epiglottis
cricoid cartilage
-complete ring (looks like a signet ring), thicc in the back-narrow in the front
-articulates with the thyroid cartilage via the cricothyroid joint
thyroid cartilage
-largest laryngeal cartilage
-articulates with the cricoid cartilage - allows it to rock forward and backward
epiglottis
-leaflike cartilage (only non-hyaline cartilage)
-folds to protect the airway during swallowing
paired cartilages
-arytenoid cartilages, corniculate, cuneiform
arytenoid cartilages
-shaped like a tetrahedron
-sits on the thicc part of the cricoid
-articulates with the cricoid for a wide range of movement: rocks, slides, rotates
-posterior attachment of vocal folds (muscular process - attachment for abductory and adductory muscles, vocal process - attachment for vocal folds muscles
movement of the arytenoids
rocking - allows vocal folds to adduct and abduct, shorten and lengthen slightly
gliding - anterolaterally, affects vocal fold length
very little rotating - around the vertical axis
cuneiform cartilages
-reside within the aryepiglottic folds (to provide support)
corniculate cartilages
-ride on superior surface of each arytenoid
-landmark in the aryepiglottic folds
hyoid bone
-union between tongue and laryngeal structures
-point of attachment of many extrinsic laryngeal muscles
-loosely articulates with the superior cornu/horns of the thyroid cartilage
vocal folds are bands of __
-tissues that can be adducted/abducted
medial laryngeal surface is covered in ___
mucous membrane
extrinsic ligaments vs intrinsic ligaments
-extrinsic means one end is connected outside of the larynx (like the hyoid or trachea), intrinsic means it’s all contained within the larynx.
extrinsic ligaments/laryngeal membranes
-attachments between hyoid or trachea and the cartilages of the larynx
-attachments to the epiglottis
attachments between hyoid or trachea and the cartilages of the larynx (6)
-thyrohyoid membrane (in between the thyrohyoid ligaments)
-lateral thyrohyoid ligament
-median thyrohyoid ligament
-hyoepiglottic ligament
-thyroepiglottic ligament
-cricotracheal ligament
attachments to the epiglottis (3.5)
-hyoepiglottic ligament
-thyroepiglottic ligament: small stem at base of epiglottis
-glossoepiglottic ligament: connects the tongue to the epiglottis
–valleculae: space between the glossoepiglottic ligament and the frenulum looking thing in the middle.
intrinsic ligaments/laryngeal membranes (4)
-connect cartilages that provide support for the larynx
-fibroelastic membranes: upper quadrangular membrane, aryepiglottic folds, lower conus elasticus, and vocal ligament
quadrangular membrane connects the:
arytenoids, epiglottis, thryoid
superior boundary of the quadrangular membrane
aryepiglottic fold
cavities of the larynx (5)
-aditus
-vestibule
-laryngeal ventricle
-glottis
-conus elasticus
aditus
entry to the larynx from the pharynx
vestibule
space between aditus and ventricular folds or false vocal folds
lateral walls of vestibule are formed by
aryepiglottic folds and quadrangular membrane
laryngeal ventricle
-or ventricular space, space between the ventricular folds and true vocal folds
-contains mucus glands (laryngeal saccule) to lubricate the vocal folds
glottis
-space between the vocal folds
conus elasticus
-inferior surface of true vocal folds to inferior border of cricoid cartilage
false vocal folds
-ligament, muscle, and mucosal surface
-thicker/heavier than true vocal folds
-used to lubricate true VF, limited protective function
-attach at an angle of the thyroid, and lateral surface of the arytenoid
5 layers of the vocal folds
-epithelium
-lamina propria: superficial, intermediate, deep
-thyroarytenoid muscle
VF epithelium
-non-keratinized, stratified, non-ciliated, squamous cells
-protects against abrasion and strong contact forces
-contains channels and microvilli
-anchored by the BASEMENT MEMBRANE ZONE to superior layer of the lamina propria
basement membrane zone (BMZ)
-anchors the VF epithelium to the superficial lamina propria
-two layers with diff types of collagen fibers
3 layers of the lamina propria
-superior layer of the lamina propria (sllp)
-intermediate layer of the lamina propria (illp)
-deep layer of the lamina propria (dllp)
superior layer of the lamina propria (sllp)
-“reinke’s space”
-more gel like, so fewer elastic fibers
-looser more pliable
intermediate layer of the lamina propria (illp)
-more elastic fibers, some collagenous fibers
deep layer of the lamina propria (dllp)
-some elastic fibers, more collagenous fibers
ILLP + DLLP
-vocal ligament (white color)
Interaction of the musculature
-muscles work together (they don’t work in isolation)
-intrinsic muscles: fine adjustments for phonation control
-extrinsic muscles: raise and lower the larynx for swallowing
intrinsic laryngeal muscles (primary movers, innervated by)
-all within the larynx
-primary movers of vocal folds: adduct/abduct, shorten/lengthen, tense/relax
-innervated by branches of CN X (vagus nerve): recurrent laryngeal nerve (RLN) and superior laryngeal nerve (SLN)
types of intrinsic muscles (4)
-adductors, abductors, tensors, relaxers
adductors (3)
-lateral cricoarytenoid, oblique arytenoid, transverse arytenoid (strongest to least)
lateral cricoarytenoid (origin, insertion, course, function, innervation)
-origin: cricoid, insertion: muscular process of the arytenoid
-courses up and back
-function: pulls the muscular process forward, rocks arytenoids forward and down, adducts vocal folds together
-innervated by recurrent laryngeal nerve
-strongest
RLN (how it branches out)
CN X comes down from the brainstem and branches out.
-branch comes down, loops around the aorta on the left, around the subclavian artery on the right, and comes back up to the larynx.
transverse interarytenoid (origin, insertion, course, function, innervation)
-origin and insertion: arytenoid cartilages
-horizontal so it courses transverse / lateral
-function: pulls arytenoids together
-innervated by RLN
oblique interarytenoid (origin, insertion, course, function, innervation)
-origin is the base of one arytenoid and it inserts to the peak or apex of another arytenoid
-courses up and diagonal
-RLN
abductor
-posterior cricoarytenoid
posterior cricoarytenoid (origin, insertion, course, function, innervation)
-origin: posterior cricoid lamina, inserts to the muscular process of the arytenoid
-rocks arytenoids back and out
-ABDUCTS!
-RLN
tensors
-cricothyroid muscle: pars recta, pars oblique (lateral), thyrovocalis
cricothyroid muscle (origin, insertion, course, function, innervation)
-origin: anterior medial cricoid
-pars recta: inserts to the lower surface of the thyroid lamina
-pars oblique: inserts to the thyroid lamina and the inferior cornu of the thyroid
-lengthens and tenses the vocal folds - raises the pitch
-JOB IS TO STRETCH (tense) THE VOCAL FOLDS
-innervated by the SLN (branch of CN X)
SLN (how it moves)
-from the brainstem goes straight to the larynx
-it’s high up that’s why superior
thyrovocalis (origin, insertion, function, innervation)
-medial portion of the thyroarytenoid
-origin: inner thyroid cartilage
-insertion: the vocal process of the arytenoid
-bulk of the vocal folds
-affects VF tension
-RLN
relaxers
-thyromuscularis - most muscular portion of the vocal folds
thyromuscularis
-same as thyrovocalis
-lateral portion
auxillary musculature
thyroepiglottic - dilates laryngeal opening, aryepiglottic muscle - folds epiglottis over for swallowing
extrinsic muscles
-one point of insertion outside the larynx
-primary movers of larynx as a whole: up/down, stabilizes the larynx when things around are moving, CRITICAL FOR SWALLOWING
-innervated by various cranial and spinal nerves
hyoid and laryngeal elevators (7)
-digastricus, stylohyoid, mylohyoid, geniohyoid, hyoglossus, genioglossus, thyropharyngeus
digastricus pair (origin, insertion, course, function, innervation)
anterior belly: origin is behind chin to hyoid - pulls hyoid up and forward, innervated by CN V
posterior belly: mastoid process of temporal bone - pulls hyoid up and back, innervated by CN VII
course: medial and down
stylohyoid (origin, insertion, course, function, innervation)
origin: styloid process of the temporal bone
insertion: hyoid
course: medial and down
function: elevates and retracts hyoid
innervated by CN VII
mylohyoid (origin, insertion, course, function, innervation)
origin: inner surface of mandible, floor of the oral cavity
insertion: hyoid
function: elevates hyoid / depresses mandible
innervated by CN V
geniohyoid (origin, insertion, course, function, innervation)
origin: mental spines, inner surface of mandible
insertion: hyoid
function: elevates and draws hyoid forward
CN XII
genioglossus (origin, insertion, course, function, innervation)
origin: mental spines, inner surface of mandible
insertion: tongue and hyoid
function: tongue muscle and hyoid elevator
CN XII
hyoglossus (origin, insertion, course, function, innervation)
origin: hyoid
insertion: sides of tongue
function: elevates hyoid, depresses tongue
CN XII
thyropharyngeus (origin, insertion, course, function, innervation)
function: part of inferior pharyngeal constrictor-elevates larynx
origin: thyroid lamina and inferior cornu
insertion: pharyngeal raphe
CN X
hyoid and laryngeal depressors (4)
-sternohyoid
-sternothyroid
-omohyoid
-thyrohyoid
sternohyoid
-sternum and hyoid
-depresses hyoid
sternothyroid
-depresses thyroid
omohyoid
- 2 bellies: inferior and superior depresses hyoid and larynx
thyrohyoid
depresses hyoid or raises larynx
