slhs2203: anatomy of the phonatory system

phonation

the conversion of air into acoustic energy

subglottal pressure

the air that builds up from the lungs under the vocal folds

glottis

space between the vocal folds

transglottal pressure exchange

causes the vocal folds to adduct to complete a cycle of vibration

where does phonation occur?

larynx

laryngeal cartilages

paired: arytenoids, corniculates, cuneiforms

unpaired: cricoid, thyroid, epiglottis

arytenoids

attach to the vocal folds andn allow for movement, tension, and relaxation

corniculates

sit atop the arytenoids and are horn-shaped

cuneiforms

located posterior and superior to the corniculates; provide structure and are covered by aryepiglottic folds

thyroid

largest cartilage; located superior to thyroid gland; forms laryngeal prominence

cricoid

located at the level of the C6 vertebra; encircles the larynx and attaches to the 1st cartilaginous tracheal ring

epiglottis

leaf-shaped; closes during swallowing to protect airway

adductors

closes vocal folds

abductors

opens vocal folds

intrinsic muscles

control the opening, closing, tensing, and lengthening of the vocal folds

abductor muscles

posterior cricoarytenoid

adductor muscles

transverse/oblique arytenoid, lateral cricoarytenoid, cricotyroid

thyroarytenoid

shorten and relax vocal folds; lowers pitch

cricothyroid

lengthens, tightens, and thins vocal folds; increases pitch

extrinsic muscles

provide support and stability for the larynx

suprahyoid muscles

elevates larynx; digastric, geniohyoid, mylohyoid. stylohyoid

infrahyoid muscles

depresses larynx; omohyoid, thyrohyoid, sternohyoid, sternothyroid

digastric

elevates hyoid bone and depresses mandible

geniohyoid

elevates hyoid bone and depresses mandible

mylohyoid

elevates floor of mouth, tongue, and hyoid bone

stylohyoid

initiates swallowing by pulling hyoid posteriorly and superiorly

omohyoid

depressed hyoid and larynx; active during esophageal phase of swallowing

thyrohyoid

depresses hyoid; elevates thyroid ghland

sternohyoid

depresses hyoid and larynx

sternothyroid

depresses thyroid cartilage and larynx

vocal folds

two mucous membranes stretched horizontally; attaches anteriorly to thyroid and posteriorly to arytenoid

hyoid bone

U-shaped bone located anteriorly; serves as point of attachment for extrinsic laryngeal muscles, floor of mouth, tongue, pharynx, and epiglottis; involved in speech, swallowing, and breathing