anatomy of phonation ch. 4. spoken communication voiceless phonemes or speech sounds- produced...
TRANSCRIPT
Anatomy of Phonation
Ch. 4
Spoken CommunicationVoiceless phonemes or speech sounds-
produced without the use of the vocal folds /s/, /f/
Voiced sounds are produced by action of the vocal folds /z/, /v/
Phonation is voicing, the product of vibrating vocal folds
Respiration is the energy source that permits phonation to occur
Vocal Folds
Made up of five layers of tissue with the deepest layer being muscle
Space between the vocal folds is glottis
Area below the vocal folds is subglottal region
Functions of the LarynxPhonation
Sphincter-vocal folds are capable of a strong and rapid clamping of the airway to keep foreign objects out
Hold your breath
Lifting heavy objects/Childbirth- “fix” or anchor your larynx which provides muscles of upper body a solid framework
Framework of Larynx A musculocartilaginous
structure
Comprised of three unpaired and three paired cartilages bound by ligaments and lined with mucous membrane
Oddly shaped box that sits atop the last ring of the trachea
Adjacent to cervical vertebrae 4-6 in the adult
Average length is 44mm- males, 36 mm- females
Cavities of Larynx
Aditus- entry to the larynx
Vestibule- space between the aditus and the ventricular folds (false vocal folds)
Laryngeal ventricle- middle space of the larynx Lies between the margins
of the false vocal folds and true vocal folds
Cricoid Cartilage Complete ring resting atop
the trachea Most inferior of the laryngeal
cartilages Posterior quadrate lamina-
provides point of articulation for arytenoid cartilages
Lateral surface- point of articulation for inferior horns of thyroid cartilage
Cricothyroid joint- diathrodial, pivoting joint permits rotation of the two structures
Would fit loosely on your little finger
Thyroid Cartilage Unpaired cartilage Largest of the cartilages Articulates with the cricoid
cartilage below Paired processes allow it
to rock forward and backward
Prominent anterior surface made of two places- thyroid laminae
Joined at the midline- thyroid angle
Superior most point is the thyroid notch (adam’s apple)
Thyroid Cartilage Vocal folds attach to the
thyroid just behind the thyroid notch
Posterior aspect is open- two prominent sets of cornu or horns
Inferior cornu project downward to articulate with the cricoid cartilage
Superior corner project superiorly to articulate with the hyoid
Arytenoid Cartilages Ride on the high-backed
upper surface of the cricoid cartilage
Form the posterior point of attachment for the vocal folds
Paired cartilage Vocal processes project
anteriorly toward thyroid notch, posterior portion of the vocal folds attach
Muscular process forms the lateral outcropping of the arytenoid pyramid- point of attachment for muscles that adduct/abduct the vocal folds
Corniculate Cartilage
Corniculate cartilages
Ride on the superior surface of each arytenoid cartilage
Prominent landmarks in the aryepiglottic folds
Epiglottis Unpaired cartilage
Leaf-like structure arises from the inner surface of the thyroid cartilage just below the notch
Attached by the thyroepiglottic ligament
Sides are joined with the arytenoid cartilages via the aryepiglottic folds
Projects upward beyond the larynx and above the hyoid bone
Epiglottis Attached to the root of the
tongue by glosso-epiglottic fold and lateral glosso-epiglottic ligamets
This juncture produces the valleculae
Pyriform sinuses- lateral recesses
Attached to the hyoid bone via the hyoepiglottic ligament
Surface is covered with a mucous membrane lining
Cuneiform cartilages Small cartilages
embedded within the aryepiglottic folds
Situated above and anterior to the corniculate cartilages
Provide support for the membranous laryngeal covering
Hyoid Bone Provides the union between the
tongue and the laryngeal structure
Unpaired small bone
Articulates loosely with the superior cornu of the thyroid cartilage
U-shaped, being open in the posterior side
Corpus or Body- forms the front of the bone, point of attachment for six muscles
Greater cornu- lateral surface of the corpus projecting posteriorly
Lesser cornu-found at the junction of the corpus and greater cornu
Extrinsic ligaments Thyrohyoid membrane-
stretches between the greater cornu of the hyoid and lateral thyroid
Lateral Thyrohyoid ligament-superior cornu of the thyroid to posterior tip of the greater cornu hyoid
Median Thyrohyoid ligament- from corpus hyoid to upper border of the anterior thyroid
Together- these three connect the larynx and the hyoid bone
Extrinsic ligaments
Hyoepiglottic ligament/Thyroepiglottic ligament- attach the epiglottis to hyoid and inner thyroid cartilage, just below the notch
Cricotracheal ligament-attaches the trachea to the larynx
Intrinsic ligaments Connect the cartilages of the
larynx and form the support structure for the cavity of the larynx and vocal folds
Quandrangular membranes Layer of connective tissue
running from the arytenoids to the epiglottis and thyroid cartilage
Form false vocal folds Originate at inner thyroid
angle and sides of epiglottis and form an upper cone that narrows and terminates at the arytenoid and corniculate cartilages
Intrinsic ligaments Aryepiglottic muscles
From the side of the epiglottis to the arytenoid
Form the upper margin of the quadrangular membrane
Form the aryepiglottic folds Folds are simply the ridges
marking the highest elevation of these membranes
Pyriform sinus is the space between the aryepiglottic fold and the thyroid cartilage
Vocal Fold Structure Most superficial layer-
protective layer of epithelium Glistening white appearance Protective layer
Second layer- superficial lamina propria (SLP)- elastin fibers Stretched cushions
Third layer- Intermediate lamina propria (ILP)- elastin fibers running in an A-P
direction provide elasticity and strength
Vocal Fold Structure Fourth layer- Deep lamina
propria (DLP)- Collagen fibers that prohibit
extension
ILP and DLP combine to make up the vocal ligament Stiffness and support
Fifth layer-Thyroarytenoid muscle- active element of the vocal
folds
Mucosal lining- combination of the epithelial lining and first layer
Movement of the Cartilages
Cricothyroid and Cricoarytenoid joints are the only functionally mobile points of the larynx
Cricothyroid joint- junction of cricoid cartilage and inferior cornu of the thyroid cartilage Diarthrodial (synovial) joint that
permit the cricoid and thyroid to rotate and glide
Rotation permits the thyroid cartilage to rock down in front
Permits the thyroid cartilage to glide forward and backward slightly
Provides the major adjustment for change in vocal pitch
Movement of the Cartilages
Cricyarytenoid joint Formed between the cricoid
and arytenoid cartilages Synovial joints permit
rocking, gliding and minimal rotation
Rocking action permits two vocal processes toward each other permitting the vocal folds to approximate
Arytenoids glide on the long axis which changes vocal fold length
Arytenoids rotate upon a vertical axis which permits abduction
Intrinsic Laryngeal Muscles
Have both origin and insertion on laryngeal cartilages
Make fine adjustments to the vocal mechanism
Assume responsibility for opening, closing, tensing, lengthening and relaxing the vocal folds
Movement of the vocal folds into and out of approximation is achieved by the coordinated effort of many of the intrinsic muscles of the larynx
Changing pitch is reflected by a change in mass or tension
Intrinsic Laryngeal Muscles
Lateral Cricoarytenoid Muscle Attaches to the cricoid
and the muscular process of arytenoid
Muscular process will be drawn forward
Rocks the arytenoid inward and downward
Adduction of vocal folds Lengthens the vocal folds Innervated by X vagus
nerve
Intrinsic Laryngeal Muscles
Transverse Arytenoid Muscle Runs between the two
arytenoid cartilages on the posterior surface
Pulls the two arytenoids closer together
Approximates the vocal folds Increased medial
compression which is increased force of adduction
Vital element in vocal intensity change
Innervation by the Recurrent laryngeal nerve of the X vagus
Intrinsic Laryngeal Muscles
Oblique Arytenoid Muscles Paired muscles Originate at the posterior base
of the muscular process and course obliquely up to the apex of the opposite arytenoid
Form an “X” Pull the apex medially Promotes adduction Enforces medial compression Rocks arytenoid and vocal folds
down and in Aids in pulling the epiglottis to
cover the opening to the larynx Innervation- Recurrent
laryngeal nerve of the X Vagus
Intrinsic Laryngeal Muscles
Posterior Cricoarytenoid muscle Sole abductor of the vocal
folds Originates from the
posterior cricoid lamina Project up to insert into the
posterior aspect of the muscular process of the arytenoid cartilage
Pulls muscular process posteriorly
Rocks the arytenoid cartilage
Abducts the vocal folds
Intrinsic Laryngeal Muscles
Cricothyroid Muscle- composed of two heads Pars Recta- originates on the
anterior surface of cricoid cartilage and courses up to the lower surface of the thyroid lamina
Pars oblique- arises from the lateral cricoid cartilage to the point of juncture between the thyroid laminae and inferior horns
Both tense the vocal folds Together they are the major
contributors for pitch change Innervated by the Superior
Laryngeal Nerve of the X Vagus
Intrinsic Laryngeal Muscles
Pars RectaRocks the thyroid cartilage downwardBrings thyroid and cricoid closer together in frontMakes the posterior cricoid more distant from the
thyroidVocal folds are stretched
Pars ObliqueThyroid slides forwardTense the vocal folds
Intrinsic Laryngeal Muscles
Thyrovocalis Muscle (abbreviated as vocalis) Medial muscle of the vocal
folds Originates from the inner
surface of the thyroid cartilage Inserts into the lateral surface
of the arytenoid vocal process Contraction draws the thyroid
and cricoid cartilages farther apart in front
Glottal tensor- tenses the vocal folds
Innervated by the Recurrent Laryngeal Nerve of the X Vagus
Intrinsic Laryngeal Muscles
Thyromuscularis Muscle Paired muscle Immediate lateral to each
vocalis muscle Originates on the inner
surface of the thyroid cartilage near the notch
Inserts into the arytenoid cartilage at the base
Laryngeal relaxer Relaxes the vocal folds Innervated by the
Recurrent Laryngeal Nerve
Extrinsic Laryngeal Muscles
Muscles with one attachment to a laryngeal cartilage
Laryngeal elevators- muscles that elevate the hyoid and larynx
Laryngeal depressors- those that depress the hyoid and larynx
Elevators Digastricus- two separate
bellies- elevates the hyoidAnterior- originates on the inner surface of
the mandible near the point of fusion
Inserts into hyoid hyoid draws up and forward. Innervated by the V Trigeminal
Posterior – originates on the mastoid process
of the temporal bone and inserts into the hyoid at the
juncture of the hyoid corpus and greater cornu
hyoid draws up and back. Innervated by the the VII facial
Elevators Stylohyoid Muscle
Originates on the styloid process of the temporal bone
Courses down and inserts into the corpus of the hyoid
Elevates and retracts the hyoid bone
Innervated by the VII facial nerve
Elevators Mylohyoid Muscle
Originates on the underside of the mandible
Courses to the corpus hyoid
Fanlike muscle Forms the floor of the
oral cavity Innervated by the V
trigeminal nerve
Elevators Geniohyoid
Superior to the mylohyoid
Projects in a course parallel to the anterior belly of the digastricus from the inner mandibular surface down to the hyoid bone at the corpus
Elevates the hyoid and draws it forward
Innervated by the XII hypoglossal nerve arising from the first cervical spinal nerve
Elevators Hyoglossus Muscle
Laterally placed muscle Originates from the
superior surface of the greater cornu of the hyoid and
inserts into the side of the tongue
Innervated by the the XII hypoglossal
Elevators Genioglossus Muscle
Hyoid elevator and tongue depressor
Originates on the inner surface of the mandible and then down
insert into the tongue and anterior surface of the hyoid corpus
Innervated by the XII hypoglossal
Elevators Thyropharyngeus Muscle-
Originates from the thyroid lamina and courses up
Inserts into the posterior pharyngeal raphe
Elevates the larynx Constricts the pharynx Innervated by the RLN of
the X Vagus
Depressors Sternohyoid muscle
Runs from the sternum to the inferior margin of the hyoid
Depresses the hyoid Fixes the hyoid and
larynx Lowering is clearly
evident following the pharyngeal stage in swallowing
Innervated by the ansa cervicalis
Depressors Omohyoid Muscle
Has two bellies Superior belly terminates
on the side of the hyoid corpus
Inferior belly has its origin on the upper border of the scapula
Passes deep to the sternocleidomastoid
Depresses the hyoid bone and larynx
Innervated by the ansa cervicalis
Depressors Sternothyroid muscle
Depresses the thyroid cartilage
Originates from the sternum and first costal cartilage
Inserts into the oblique line of the thyroid cartilage
Innervated by fibers of the spinal nerves
Depressors Thyrohyoid muscle
Originates from the thyroid cartilage to the
Inserts into the inferior margin of the greater cornu of the hyoid bone
Depress the hyoid or raises the larynx
Innervated by the spinal nerve
Laryngeal StabilityStability is the key to control
Gained through the development of the infra and suprahyoid musculature
Larynx is intimately linked via the hyoid bone, to the tongue
Movement of the tongue is translated to the larynx
Vocal Fold ParalysisMost frequent cause- damage to the nerve during
thyroid surgery or carotid surgery, blunt trauma, CVA, or aneurysm
One side of the Recurrent Laryngeal Nerve is damaged (lower motor neuron)- unilateral vocal fold paralysis
Bilateral nerve damage=Bilateral paralysis
Adductor paralysis-muscles of adduction are paralyzed and vocal folds remain in the abducted position
Abductor paralysis-cannot abduct the folds, respiration is compromised
Vocal Fold ParalysisDamage to Superior Laryngeal nerve results in
inability to alter pitch
Unilateral paralysis- one vocal fold is still capable of motion and phonation can still occur but it will be breathy
Bilateral adductor paralysis results in virtually complete loss of phonation