2. Advanced Laryngeal physiology 2018
Transcript of 2. Advanced Laryngeal physiology 2018
![Page 1: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/1.jpg)
Advanced Laryngeal Physiology
Sarah Perry, Ph.D. CCC-SLP
![Page 2: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/2.jpg)
Position of the Larynx
• The Larynx: • Sits opposite approximately the
third, fourth, fifth, and sixth cervical vertebrae
• In a child the larynx sits opposite approximately the fourth cervical vertebrae
![Page 3: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/3.jpg)
Structure of LarynxHyoid Bone
Thyroid Cartilage
Cricoid Cartilage
EpiglottisCorniculate Cartilages
Arytenoid Cartilages
Anterior Posterior
![Page 4: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/4.jpg)
Structure of Larynx
Anterior
Posterior
Superior view
Hyoid Bone
Thyroid Cartilage
Epiglottis
Thyroid Cartilage
![Page 5: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/5.jpg)
Structure of Larynx
Anterior
Posterior
Superior view (Epiglottis removed)
Hyoid Bone
Thyroid Cartilage
Thyroid Cartilage
Arytenoid Cartilages
Vocal Ligaments (Part of Vocal
Folds)
![Page 6: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/6.jpg)
Structure of Larynx
Anterior
Posterior
Superior view
Epiglottis
Arytenoid Cartilages
Vocal Folds
![Page 7: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/7.jpg)
Basic Structures of the Larynx
• Glottis: the space between the vocal folds • Size and shape changes as a function of the
vibratory behavior of the vocal folds • Abduction: wide glottis • Adduction: closed glottis
![Page 8: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/8.jpg)
Framework of the Larynx• Supraglottal cavity
• From the vocal folds to the aryepiglottic folds
• Ventricles • Lateral space between
ventricular and true vocal folds
• Subglottal cavity • From the vocal folds to the first
tracheal ring
![Page 9: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/9.jpg)
Hyoid Bone• The only laryngeal bone
• U-shaped
• The only bone in the body that is not attached to another bone
• Hyoid has a body with lateral horns (greater and lesser cornu)
Anterior
![Page 10: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/10.jpg)
Prominent Landmarks of the Hyoid Bone
Anterior
Posterior
Superior view
Greater cornu (for laryngeal
muscle attachment)
Lesser cornu (for laryngeal muscle
attachment)
Corpus (the portion you can
palpate)
![Page 11: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/11.jpg)
Laryngeal CartilagesSix cartilages that occur singly or in pairs
1. Thyroid (1)
2. Cricoid (1)
3. Arytenoids (2)
4. Corniculated (2)
5. Cuneiforms (2)
6. Epiglottis (1)
Thyroid Cartilage
Cricoid Cartilage
Corniculate Cartilages
Arytenoid Cartilages
Posterior view
![Page 12: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/12.jpg)
Thyroid Cartilage• Unpaired • Hyaline cartilage • Superior cornu
• Attaches indirectly to the greater cornu of the hyoid bone
• Inferior cornu • Attaches posteriorly to the cricoid
cartilage • Laryngeal prominence/Thyroid notch
Posterior View
Anterior
![Page 13: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/13.jpg)
Cricoid Cartilage
• Unpaired
• Hyaline cartilage
• Sits on top of the trachea
• Shaped like a signet ring
• Complete circle
![Page 14: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/14.jpg)
Epiglottis• The only other unpaired cartilage
• Leaf-shaped • Can sometimes be omega shaped Ω
• Elastic cartilage • Petiolus: Attaches to the inside of the
thyroid – epiglottis becomes very thin at this point
• Anterior surface attaches to the hyoid bone by ligaments • Also attaches to the root of the
tongue
![Page 15: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/15.jpg)
Epiglottis
• Biological function: inverts to close off airway directing food/bolus material toward esophagus during swallowing
• Non-biological function: Tongue position moves epiglottis but no real function for phonation or articulation • Exception: consonants in a few languages (e.g.
Arabic, Hebrew)
![Page 16: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/16.jpg)
Aryepiglottic Fold• A fold of mucous membrane, enclosing ligamentous
and muscular fibers • Stretches between the side of the epiglottis and the
apex of the arytenoid cartilages
• The AE folds form the upperborders of the quadrangularmembrane
• The AE folds can phonate (e.g. Louis Armstrong vocal growl)
![Page 17: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/17.jpg)
Arytenoid Cartilages• Largest of the paired cartilages • Hyaline (mostly) + elastic • Sit on top of the superior surface of the
posterior cricoid cartilage
• Control abduction and adduction of the vocal folds
• Pyramid shaped: apex and base • Corniculate cartilages rest on the apex
![Page 18: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/18.jpg)
Arytenoid Cartilages• Lateral projection
• Muscular process • For adduction, abduction of
vocal folds • Anterior projection
• Vocal process • Attached to posterior part of
the vocal folds
![Page 19: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/19.jpg)
Movements of Arytenoid Cartilages
• Rocking: forward and backward • Moves vocal processes closer
together for vocal fold vibration
• Gliding • Shortens or lengthens vocal folds
![Page 20: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/20.jpg)
Corniculated Cartilages • Paired cartilages
• Elastic cartilages
• Sit on top of the apex of the arytenoid cartilages
• Pyramid shaped
• Assist with attachment of VFs to arytenoids
![Page 21: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/21.jpg)
Cuneiform Cartilages• Tiny, paired, wedge-shaped
cartilages • Elastic cartilages • Embedded in the mucous
membrane • Superior and anterior to the
corniculate cartilages • Biological function:
• Supportive framework for the aryepiglottic fold
• Vestigial - not all people have them
![Page 22: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/22.jpg)
Framework of the Larynx
• The cartilages and bone of the larynx are held together by a series of ligaments (connective tissue) • Seven of these are extrinsic
• They connect somewhere on the outer surface of the larynx
• Three are intrinsic • Both attachments are within the larynx
![Page 23: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/23.jpg)
Extrinsic Ligaments/Membranes
• Three ligaments connect the hyoid bone to the thyroid cartilage, and their names reflect this connection:
• Thyrohyoid membrane
• Lateral thyrohyoid ligament
• Middle thyrohyoid ligament
![Page 24: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/24.jpg)
Extrinsic Ligaments/Membranes
• Three ligaments connect the epiglottis to the: • Hyoid bone !
Hyoepiglottic ligament • Thyroid cartilage !
Thyroepiglottic ligament • Tongue !
Glossoepiglottic ligaments
![Page 25: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/25.jpg)
Extrinsic Ligaments/Membranes
• Cricotracheal membrane • Connects the cricoid cartilage to
the trachea
![Page 26: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/26.jpg)
Intrinsic Ligaments/Membranes
• Cricothyroid ligament • Composed of 2 parts:
• Median cricothyroid ligament • Lateral cricothyroid
ligaments (conus elasticus)
![Page 27: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/27.jpg)
Intrinsic Ligaments/Membranes
• Vocal ligament • An intrinsic ligament within
the vocal folds; connects the vocal process of the arytenoid to the thyroid cartilage
![Page 28: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/28.jpg)
The Vocal Folds• Consist of 5 layers
(as per Hirano) 1. Epithelium 2. Superficial Layer of
the Lamina Propria 3. Intermediate Layer of
the Lamina Propria 4. Deep Layer of the
Lamina Propria 5. Thyrovocalis muscle
![Page 29: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/29.jpg)
![Page 30: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/30.jpg)
Epithelium
• Epithelium • Thin covering (100−180μm) of the vocal folds,
protecting them from their intrinsic and extrinsic environment
• Pearly white tissue • Hydrates the tissue • Can regenerate
![Page 31: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/31.jpg)
Lamina Propria
• Superficial Layer (“Reinke’s Space”) • The main vibrating proportion of the vocal folds • The epithelium and superficial
layer are commonly referred to as the “cover”
• Cushions the vocal folds; lots of elastin fibers
![Page 32: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/32.jpg)
Lamina Propria
• Intermediate Layer • Composed mainly of elastic fibers which run
parallel to the vibrating edge of the vocal fold, allowing this layer to only stretch in an antero-posterior direction
![Page 33: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/33.jpg)
Lamina Propria• Intermediate + deep layers = vocal ligament
• Each vocal ligament is a band of yellow elastic tissue attached anteriorly to the thyroid cartilage and posteriorly to the vocal process of the arytenoid cartilage
![Page 34: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/34.jpg)
Lamina Propria• Deep Layer
• Composed mainly of collagenous fibers which run parallel to the vibrating edge of the vocal fold
• Deep layer of lamina propria + thyrovocalis muscle = the “body”
![Page 35: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/35.jpg)
Anatomy of the Vocal Folds• The most medial portion of the thyrovocalis muscle
makes up the bulk of the vocal fold structure • Tenses the vocal folds for vibration
![Page 36: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/36.jpg)
The Extracellular Matrix (ECM)
• “Filler” substance that exists between cells in an organism
• The ECM plays an important role in cell function, particularly in protection against damage and in recovery
• In the vocal folds, the lamina propria is rich in ECM within all layers (superficial, intermediate and deep)
![Page 37: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/37.jpg)
Hyaluronic Acid (HA)• A chief component in the ECM • HA molecules hold up to 100x their weight in water
• Important for impact absorption • Amount of HA is variable between individuals (genetic
factors?) • The abundant amount of HA observed
in the female vocal folds is thought to be related to impact absorption
• Acts as protection against the characteristic high vibration frequency of the female vocal folds
![Page 38: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/38.jpg)
Ventricular Vocal Folds• Consist of a thick layer of mucous membrane and a
supportive ligament (lower edge of quadrangular membrane)
• Not directly involved in voice • When they are, it is called
diplophonia
• Lubricate vocal folds with mucous and assist in airway protection during swallowing
![Page 39: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/39.jpg)
Ventricular Vocal Folds
![Page 40: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/40.jpg)
Adult Male and Female Differences in Laryngeal Anatomy
• The most apparent differences: • A larger thyroid lamina in males • A more acute thyroid angle in males, giving
prominence to the thyroid notch or “Adam’s apple” • Thicker vocal folds in males • Larger glottal space in males
![Page 41: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/41.jpg)
Changes in VF Structure Through the Lifespan
• Newborns • No layered structure of LP • LP loose and pliable
• Children • Vocal ligament appears 1-4
yrs • 3-layered LP is not clear until
15 yrs
• Old age • Superficial layer
becomes edematous & thicker
• Thinning of intermediate layer and thickening of deep layer
• Changes in LP more pronounced in men
• Muscle atrophy
![Page 42: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/42.jpg)
Age Effects on Laryngeal Anatomy
• The following parameters differentiate a young from an older larynx: • Vocal fold bowing (inward curvature) • Prominence of the vocal process • Tremor of the laryngeal
structures • Presbylaryngis: age-related
changes to the larynx • Presbyphonia: age-related
changes to the voice
![Page 43: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/43.jpg)
Muscles of the Larynx
![Page 44: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/44.jpg)
Introduction to the Muscles of the Larynx
• 2 types • Extrinsic muscles
• When contracted, set the entire larynx in motion (raising it or lowering it)
• Intrinsic muscles • When contracted, affect the structure of the
vocal folds during phonation
![Page 45: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/45.jpg)
Extrinsic Laryngeal Muscles• We have eight paired extrinsic laryngeal muscles:
Four Elevators Digastrics: anterior + posterior
bellies Geniohyoids
Mylohyoids
Stylohyoids
Four Depressors Thyrohyoids
Sternohyoids
Omohyoids
Sternothyroids
![Page 46: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/46.jpg)
Extrinsic Laryngeal Muscles
• Suprahyoids:
• Four Elevators • Digastrics: anterior +
posterior bellies • Geniohyoids • Mylohyoids (largest) • Stylohyoids
Di = two, gastric = belly Genio = chin Hyoid = Hyoid Bone Mylo = molar (lower jaw) Stylo = Styloid process of the temporal bone of the skull
![Page 47: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/47.jpg)
Extrinsic Laryngeal Muscles
• Infrahyoids:
• Four Depressors • Thyrohyoids • Sternohyoids • Omohyoids (most superficial) • Sternothyroids (deepest)
Thyro = Thyroid Cartilage
Sterno = Sternum
Omo = Shoulder
![Page 48: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/48.jpg)
Mnemonic• Experts Don’t Get Many Stylish Or Sexy Things, Sadly
Digastrics Geniohyoids Mylohyoids Stylohyoids
Omohyoids Sternohyoids Thyrohyoids
Sternothyroids
Suprahyoids ‘Elevators’
Infrahyoids ‘Depressors’
Extrinsics:
![Page 49: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/49.jpg)
Suprahyoids
![Page 50: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/50.jpg)
Digastrics • 2 muscle sections:
• Posterior belly • Anterior belly
• Origin: • Mastoid process
(for the posterior belly) • Mandible (for anterior
belly) • Insertion: intermediate
tendon connected with the hyoid bone
Mandible
Note: Only Right Digastric shown
![Page 51: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/51.jpg)
• Cylindrical muscle, lies deep (relative to the skin) on the surface of the mylohyoids
• Origin: mandibular symphysis of mandible • Insertion: anterior surface of the hyoid body • Function:
pulls the hyoid bone anterosuperiorly (and thus the larynx)
Geniohyoids
![Page 52: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/52.jpg)
Mylohyoids• Thin muscles forming the floor of the
mouth • Origin: inner surface of the
mandible • Insertion: fibers unite at midline
raphe and extend to the hyoid body
• Function: Pulls the hyoid bone anterosuperiorly (and thus the larynx)
![Page 53: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/53.jpg)
Stylohyoids• Long slender muscle located on
the surface of the posterior belly of the digastrics
• Origin: styloid process of the temporal bone
• Insertion: body of the hyoid
• Function: Elevate the hyoid bone
Note: Only Right Stylohyoid shown
![Page 54: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/54.jpg)
Infrahyoids
![Page 55: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/55.jpg)
Omohyoids• 2 bellies: inferior + superior • Function: Lower the thyroid • Superior belly
• Origin: intermediate tendon connected with the hyoid
• Insertion: great horn of the hyoid • Inferior belly
• Origin: surface of the scapula
• Insertion: intermediate tendon
Scapula
Intermediate Tendon
Note: Only Right Omohyoid shown
Hyoid bone
![Page 56: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/56.jpg)
Thyrohyoids
Hyoid bone
Thyroid CartilageNote: Only Right Thyrohyoid shown
• Shown in red • Thin muscle lying deep to the omohyoids (shown in
blue) • Origin: oblique line of
the thyroid lamina • Insertion: greater horn
(cornu) of the hyoid bone • Function: decrease distance
between thyroid and hyoid
![Page 57: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/57.jpg)
Sternohyoids• Thin muscle lying on anterior side of the neck
• Origin: Manubrium of the sternum and end of the clavicle
• Insertion: hyoid
• Function: Pulls down the hyoid bone
Note: Only Right Sternohyoid shown
![Page 58: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/58.jpg)
Sternothyroids
Thyroid Cartilage
Note: Only Right Sternothyroid shown
• Long thin muscle on anterior side of the neck
• Origin: Underneath the manubrium and costal cartilage of the first rib
• Insertion: Oblique line of the thyroid
• Function: Pulls down the thyroid
![Page 59: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/59.jpg)
Intrinsic Laryngeal Muscles
![Page 60: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/60.jpg)
Intrinsic Laryngeal Muscles• Responsible for controlling sound production • Interarytenoid:
• Oblique • Transverse
• Cricoarytenoids: • Lateral • Posterior
• Cricothyroids • Thyroarytenoids
![Page 61: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/61.jpg)
Mnemonic• In Indianna, On Thursdays, Crazy, Lanky People Cook Tacos
Interarytenoid: - Oblique
- Transverse
Intrinsics: Cricoarytenoids: - Lateral
- Posterior
Cricothyroids Thyroarytenoids
![Page 62: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/62.jpg)
Transverse Interarytenoid• Unpaired muscle • Origin: Lateral margin and
posterior surface of one arytenoid and courses to the lateral margin of the other arytenoid
• Insertion: Arytenoid of the opposite side
• Function: Adducts arytenoids/closes the glottis
![Page 63: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/63.jpg)
Oblique Interarytenoids• Superficial to the transverse interarytenoid • Origin: Base of one
arytenoid and courses to the apex of the other arytenoid
• Insertion: Arytenoid of the opposite side
• Function: Adducts arytenoids/closes the glottis
![Page 64: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/64.jpg)
• Located along the upper surface of the cricoid cartilage, lateral to the vocal folds
• Origin: Upper border of the cricoid
• Insertion: Anterior surface of the muscular process of the arytenoid
• Function: Adducts the vocal processes of the arytenoids, i.e. closing the glottis
Lateral Cricoarytenoids
Note: Only Right Lateral Cricoarytenoid shown
![Page 65: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/65.jpg)
Posterior Cricoarytenoids• A fan-shaped muscle located on the posterior surface of the
cricoid
• Origin: Posterior lamina of the cricoid
• Insertion: Posterior surface of the muscular process of the arytenoid
• Function: Abducts the arytenoids i.e. opens the glottis
![Page 66: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/66.jpg)
Cricothyroid• Located between the cricoid and
thyroid consisting of fibers oriented in 2 directions: • pars oblique and pars recta
• Origin: Arch of cricoid • Insertion: Inferior margin of the thyroid • Function: decrease the distance
between thyroid and cricoid, i.e. increase the distance between the thyroid and arytenoids !increase vocal fold tension !increase their vibration rate
![Page 67: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/67.jpg)
Thyroarytenoid• A bundle of fibers making up the
true vocal folds, divided into: • Thyrovocalis muscle
(medially and more active) • Increases VF tension to
increase pitch • Thyromuscularis muscle
(laterally and less active) • Decreases VF tension to
decrease pitch
![Page 68: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/68.jpg)
Thyroarytenoid continued
• Origin: Anteriorly, from the inner anterior surface of the thyroid
• Insertion: Along the lateral base of an arytenoid from the vocal process to the muscular process
![Page 69: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/69.jpg)
Putting it all together
![Page 70: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/70.jpg)
Rocking Motion
![Page 71: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/71.jpg)
Summary of Vocal Fold Function
• Adduction • Interarytenoids (transverse + oblique) • Lateral cricoarytenoid (LCA)
• Abduction • Posterior cricoarytenoid (PCA)
• Raising pitch • Cricothyroid, thyrovocalis
• Lowering pitch • Thyromuscularis
![Page 72: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/72.jpg)
Theories of Phonation
![Page 73: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/73.jpg)
Myoelastic Aerodynamic Theory of Voice Production
1. Vocal folds adduct
2. Air pressure builds under the vocal folds
3. Pressure moves the vocal folds laterally (lateral direction is due to elasticity of folds). Inferior border separates first
4. Vocal folds return to adducted position (Bernoulli effect)
5. Cycle is repeated hundreds of times per second
![Page 74: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/74.jpg)
• At mid and high pressures, flow separation vortices create negative pressure, sucking the VFs together along with elastic tissue recoil forces
• At low pressures, Bernoulli’s law still stands
![Page 75: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/75.jpg)
High resolution stroboscopy of the vocal folds in motion
![Page 76: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/76.jpg)
Neural Control of Voice Production
![Page 77: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/77.jpg)
Central Nervous System ControlPrecentral
gyrus
![Page 78: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/78.jpg)
Upper Motor Neuron Pathway
• UMNs initiate voluntary movement
• Originate in the motor cortex and synapse on CN nuclei in the contralateral brainstem or spinal cord
• Decussate at level of the brainstem
![Page 79: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/79.jpg)
Central Nervous System Control
• PAG projects motor commands through the nucleus retroambiguus (in the medulla)
• Nucleus retroambiguus ! nucleus ambiguus (in the reticular formation of the brainstem)
• NA contains motor nuclei for all of the intrinsic laryngeal muscles, plus motoneurons for esophageal and respiratory control
![Page 80: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/80.jpg)
Corticobulbar Tract
• Comprised of UMNs originating in the motor cortex, decussate in the brainstem
• Innervates CN nuclei
• Damage to this tract results in spasticity as well as poor initiation of motor movement
![Page 81: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/81.jpg)
Peripheral Control of Voice Production
![Page 82: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/82.jpg)
Lower Motor Neuron Pathways
• LMNs that originate in the CN nuclei are called CNs
• Synapse onto muscles
![Page 83: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/83.jpg)
Innervation of the Larynx• Primarily by the vagus nerve (CN X). Two branches:
1. Recurrent laryngeal nerve • Motor: IA, PCA, thyrovocalis, LCA • Sensory: subglottis
• Unilateral injury: hoarseness
• Bilateral injury: possible breathing/voicing difficulty, depending on position of vocal fold paralysis
![Page 84: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/84.jpg)
The Recurrent Laryngeal Nerve (RLN)
• Motor innervation to all intrinsic muscles except cricothyroid
• Sensation to the subglottic region
• Note that the left and right branches have different routes
![Page 85: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/85.jpg)
Innervation of the Larynx2. Superior laryngeal nerve
• Internal branch • Sensory innervation to
glottis and laryngeal vestibule
• External branch • Motor innervation to the
cricothyroid muscle • Injury to this branch:
weak phonation as VFs cannot be tightened
![Page 86: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/86.jpg)
Vagus Nerve – Unilateral LMN Damage
• Palate droops on ipsilesional side !mild hypernasality
• VF paralysed on ipsilesional side ! breathy/hoarse voice
![Page 87: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/87.jpg)
Vagus Nerve – Bilateral LMN Damage
• Low survival rate
• Bilateral palatal droop !severe hypernasality
• Bilateral VF paralysis !severe breathiness, inspiratory stridor
![Page 88: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/88.jpg)
Vagus Nerve – Unilateral UMN Damage
• Minimal effect on phonation and resonance because of bilateral innervation
• Harsh voice quality
![Page 89: 2. Advanced Laryngeal physiology 2018](https://reader031.fdocuments.net/reader031/viewer/2022012016/61da892af0ad453dac327767/html5/thumbnails/89.jpg)
Vagus Nerve – Bilateral UMN Damage
• Spasticity/paralysis of vocal folds
• Strained-strangled OR very breathy voice, hypernasality