Phonatory System

Phonation

A product of vibrating vocal folds, also known as voicing

Hyoid Bone

only bone in the larynx. located at the level of the 3rd cervical vertebrae. very mobile, does not connect to any other bone in the body

greater cornu

structure of the hyoid bone that articulates with the superior horns (cornu) of thyroid cartilage

Lesser cornu

structure of the hyoid bone that’s cone shaped; rises superiorly

larynx

protects the lower passageway from foreign materials. can be used to hold air in lungs. generates sound

thyroid cartilage

largest of the laryngeal cartilages. articulates inferiorly with cricoid cartilage

Thyroid Laminae

smooth flattish structure of the thyroid cartilage aka quadrilateral plates

Thyroid angle

point at which the two thyroid laminae come together

thyroid notch

superior-most point of thyroid angle

thyroid prominence

“Adam’s Apple”

Superior Cornu

located on the posterior portion of thyroid. points toward hyoid bone

Inferior Cornu

located on the posterior portion of thyroid. Rests on cricoid cartilage

Cricoid Cartilage

most inferior cartilage of larynx. unpaired, ring-shaped

Arch

low narrow portion in the front of cricoid cartilage. provides clearance for the vocal folds

posterior quadrate lamina

wide and thick portion in back of cricoid cartilage. provides point of articulation for arytenoid cartilages

arytenoid cartilages

located on superior surface of cricoid cartilage. allows for rocking, gliding, and rotating (important for onset and offset of voicing). Shaped like a pyramid. comprised of base, apex, vocal process, and muscular process

vocal process

structure of arytenoid cartilages that projects anteriorly toward the thyroid notch. location of the vocal fold attachment

muscular process

projects laterally on the arytenoid. point of attachment for muscles that adduct and abduct the vocal folds

Cuneiform cartilages

small cartilages embedded within the aryepiglottic fold. anterior to corniculate cartilages. provide support for laryngeal covering

Epiglottis Cartilage (Epiglottis)

Leaf-like structure. stem (petiolus) arises from the inner surface of the thyroid angle, just below notch. protects airway by deflecting food and liquids from being swallowed. surface of epiglottis is covered with a mucous membrane lining

cricothyroid joint

laryngeal synovial (darthrodial) joint that allows the thyroid to tilt downward. this stretches and tenses the vocal folds. joint provides the major adjustments for change in vocal pitch. junction between cricoid cartilage and the inferior cornu of thyroid cartilage

cricoarytenoid joint

laryngeal joint. concave portion of arytenoids articulates with convex portion of cricoid lamina (top back of cricoid). synovial joint (saddle joint) allows for rocking, gliding, and minimal rotation involved in adduction and abduction of vocal folds

extrinsic laryngeal membranes and ligaments

group of ligaments and membranes that connect the cartilages of the larynx to each other and to the hyoid bone and trachea

thyrohyoid membrane (hyothyroid)

connects hyoid bone to thyroid cartilage

hypoepiglottic ligament

connects epiglottis to the hyoid bone

thyroepiglottic ligament

connects the epiglottis to the thyroid

cricotracheal membrane

connects the cricoid cartilage to the first tracheal ring

intrinsic laryngeal membranes and ligaments

continuous sheet of connective tissue (elastic membrane)

aryepiglottic folds

quadrangular membrane (upper portion) that completely seals off the spaces in the laryngeal structure. directs the airstream into the aditus and upward into the resonators passageways. first line of defense against foreign objects. closes during swallowing and vomiting (prevents food/liquid from entering respiratory tract)

ventricular folds

aka false vocal folds. pink and plump. quadrangular membrane (upper portion) found between laryngeal vestibule and laryngeal ventricle. when these contract, they meet at midline, closing and sealing off the airway. close during swallowing, and during effortful activities such as lifting heavy objects. during normal phonation, these remain in quiet, open position

vocal folds

conus elasticus (lower portion) that’s white from lack of vascular supply. third line of defense in keeping foreign objects out of lungs

cricothyroid ligament

conus elasticus (lower portion) that connects the cricoid cartilage to the thyroid cartilage

laryngeal vestibule

first cavity of the larynx. area in larynx above ventricular folds. opening is called aditus

laryngeal ventricle

space between vocal folds and ventricular folds

inferior laryngeal ventricle (subglottal atrium)

portion below the true folds. extend through to the trachea

valleculae

area between tongue root and epiglottis. impaired swallow can cause food/liquid to pool in this area which increases risk for aspiration

pyriform sinus

between the lateral wall of thyroid cartilage and aryepiglotic folds. impaired swallow can cause food/liquid to pool in pyriform sinus which increases risk for aspiration

glottis

opening between vocal folds. triangular shape during quiet respiration

anterior commissure

the anterior-most region of the glottis

posterior commissure

the posterior-most region of the glottis

epithelium

cover layer of the vocal folds. mucosal covering of stratified squamous cells. needs a thin layer of mucous lubrication for best oscillation

superficial lamina propria (Reinke’s Space)

cover layer of vocal folds. extracellular gelatin matrix. helps cushion the vocal cords

intermediate lamina propria

transition/vocal ligament composed of elastic fibers. part of the vocal ligament

deep lamina propria

transition/vocal ligament composed of collagen fibers. supportive, part of vocal ligament

thyroarytenoid

body layer of the vocal folds. thyrovocalis + thyromuscularis. provides tone, stability and mass

laryngeal musculature

regulates valve openings and closings for the epiglottis valv , ventricular fold valve, and vocal fold valve. provides movement of laryngeal cartilages for speech

intrinsic laryngeal muscles

have both origin and insertion within larynx. make fine adjustments to the vocal mechanism

lateral cricoarytenoid muscle

intrinsic muscle. adducts the vocal folds

transverse arytenoid muscle

only unpaired intrinsic muscle. adducts vocal folds

oblique arytenoid muscle

intrinsic muscle. adducts vocal folds (how tightly VF are pressed against each other), rocks arytenoid and vocal folds down and inward

posterior cricoarytenoid muscle

intrinsic muscle that abducts vocal folds

cricothyroid muscle

primary tensor (tightens muscles) of the vocal folds. responsible for laryngeal adjustments associated with pitch change

pars oblique

cricothyroid muscle that rotates thyroid cartilage downward, stretches vocal folds

thyrovocalis muscle

part of thyroarytenoid. body of vocal folds and tenses vocal folds

thyromuscularis muscle

part of thyroarytenoid. relaxer muscle that shortens and relaxes vocal folds

extrinsic muscles

muscles with one attachment to the larynx and the other attachment on a structure outside the larynx. forms a network that surrounds the larynx and anchors it in position within the neck. elevates and depresses parts of the larynx

digastricus muscles (anterior and posterior)

“2 bellies”. extrinsic muscles that elevate hyoid anteriorly and posteriorly respectively. mandible to hyoid bone (anterior), mastoid process to hyoid (posterior)

stylohyoid muscle

extrinsic muscle that elevates hyoid posteriorly. styloid process (side of skull by ear) to hyoid

mylohyoid muscle

extrinsic muscle that makes up the floor of oral cavity. elevates hyoid anteriorly. molar area to hyoid

geniohyoid muscle

extrinsic muscle that elevates hyoid anteriorly. chin to hyoid

genioglossus muscle

extrinsic muscle that forms the primary muscle of the tongue. elevates hyoid. chin to tongue

hypoglossus muscle

extrinsic muscle that elevates hyoid and depresses tongue. hyoid to sides of tongue

Sternohyoid muscle

extrinsic muscle that depresses hyoid. sternum to hyoid

omohyoid muscles (superior and inferior)

extrinsic muscle that depresses hyoid. scapula to hyoid

sternothyroid muscle

extrinsic muscle that assists with producing high and low pitch. helps make fine adjustments to vocal folds. depresses thyroid cartilage, elongating vocal folds. sternum to thyroid

thyrohyoid muscle

extrinsic muscle that depresses hyoid or elevates larynx. thyroid to greater cornu of hyoid. pulls thyroid and hyoid closer (elevating larynx)

myoelastic

stretchiness of muscles. why the vocal folds return to place. due to elasticity, stiffness, and inertia

Bernoulli’s Principle

there will be an increase in velocity of airflow at a point of constriction, and a decrease in air pressure perpendicular to the flow

sustain phonation

maintain laryngeal posture, ongoing airflow maintains the vibration

frequency

rate of vibration of an object. measured in cycles per second (Hz)

Pitch

perception of sound’s frequency. vibration rate related to vocal fold thickness (mass), length, and elasticity (tension)

Higher Pitch

the faster the vibration of the vocal folds (the higher the frequency) the higher the sounds will be perceived. contraction of cricothyroid muscles which lengthens the vocal folds and thins medial edge

Lower Pitch

the slower the vibration of the vocal folds (the lower the frequency) the lower the sound will be perceived. caused by contraction of thyromuscularis which brings the thyroid cartilage and arytenoids closer together, shortening vocal fold length, and making them more massive and less tense

amplitude

amount of displacement of an object from its rest position. measured in decibels (dB)

loudness

perception of the sound’s amplitude. more of this = increased medial compression of vocal folds (they press together more tightly and for longer)

aspects of normal voice quality

maximum frequency range (voice is flexible in pitch), minimum-maximum amplitude (voice can vary in loudness), maximum phonation time (adults: 15-25s; children: at least 10s), minimal additive noise (little breathiness or roughness)

breathiness

vocal folds don’t close completely during each vibratory cycle. air leakage at the glottis creates a friction noise. this noise is measured at the higher frequencies

rough/hoarse voice

excessive vocal fold closure during phonation. vocal folds vibrate in a less periodic cycle. this noise is measured at the lower frequencies

laryngitis

inflammation of the vocal folds. caused by excessive use of the voice, infections, inhaled irritants, or reflux

vocal nodules

calluses on the vocal cords- caused by vocal abuse

vocal polyps

soft blister on vocal cords

vocal fold paralysis

one or both folds dont open or close. caused by injury, problems in surgery, stroke, cancer, neurological disorders