phonation eng 320

Hyoid bone

Unpaired bone above the thyroid cartilage; supports the tongue and larynx and is suspended by muscles and ligaments rather than directly articulating with another bone.

Thyroid cartilage

Largest unpaired laryngeal cartilage; forms much of the anterior and lateral walls of the larynx and provides the anterior attachment of the vocal folds.

Thyroid laminae

Two plates of the thyroid cartilage that join anteriorly to form the thyroid angle.

Thyroid angle

The anterior meeting point of the two thyroid laminae.

Thyroid notch

Indentation at the superior border of the thyroid cartilage.

Superior cornua

Upper projections of the thyroid cartilage that articulate with the hyoid bone.

Inferior cornua

Lower projections of the thyroid cartilage that articulate with the cricoid cartilage.

Cricoid cartilage

Unpaired, ring-shaped cartilage that forms the most inferior part of the larynx and sits directly above the trachea.

Cricoid arch

Anterior portion of the cricoid cartilage.

Cricoid articular facets

Surfaces on the cricoid where it articulates with other laryngeal cartilages.

Epiglottis

Unpaired, leaf-shaped cartilage that helps protect the airway during swallowing.

Arytenoid cartilages

Paired pyramid-shaped cartilages that sit on the superior cricoid and control vocal-fold movement.

Arytenoid apex

Top portion of the arytenoid cartilage; supports the corniculate cartilage.

Arytenoid base

Bottom portion of the arytenoid that articulates with the cricoid cartilage.

Vocal process

Anterior projection of the arytenoid; provides attachment for the vocal folds.

Muscular process

Lateral projection of the arytenoid; provides attachment for muscles that move the vocal folds.

Corniculate cartilages

Small paired cartilages located on the apices of the arytenoids.

Cuneiform cartilages

Small paired cartilages embedded in the aryepiglottic folds; provide structural support.

Triticial cartilage

Small cartilage found within the lateral thyrohyoid ligament; helps support the lateral laryngeal region.

Vocal folds

Paired tissue folds inside the larynx that can adduct, abduct, tense, relax, and vibrate to produce voiced sound.

Squamous epithelium

Outer protective layer of the vocal fold.

Superficial lamina propria

Highly elastic layer that allows the vocal folds to vibrate.

Intermediate lamina propria

Layer that contributes to the vocal ligament and provides strength.

Deep lamina propria

Layer that contributes to the vocal ligament and provides strength.

Vocal ligament

Structure formed by the intermediate and deep layers of the lamina propria.

Thyroarytenoid muscle

Deep muscular layer of the vocal fold; includes the thyrovocalis and thyromuscularis.

Thyrovocalis

Medial portion of the thyroarytenoid muscle; involved in vocal-fold tension and pitch control.

Thyromuscularis

Lateral portion of the thyroarytenoid muscle; functions as a vocal-fold relaxer.

False vocal folds

Another name for the ventricular folds; located above the true vocal folds and not normally used for phonation.

Ventricular folds

False vocal folds that lie superior to the true vocal folds.

Aryepiglottic folds

Folds extending between the arytenoid region and epiglottis; help form the laryngeal entrance and contain cuneiform cartilages.

Conus elasticus

Lower portion of the fibroelastic membrane; contributes to the support structure of the vocal folds.

Quadrangular membrane

Upper portion of the fibroelastic membrane; contributes to the supporting structures of the larynx.

Valleculae

Spaces between the tongue and epiglottis formed by the connection between the epiglottis and tongue.

Pyriform sinuses

Recesses beside the laryngeal entrance through which food passes during swallowing.

Aditus

Entrance to the larynx from the pharynx.

Vestibule

Space between the aditus and the ventricular folds.

Ventricle

Space between the false vocal folds and true vocal folds; also called the laryngeal sinus.

Laryngeal sinus

Another name for the laryngeal ventricle.

Saccule

Anterior extension of the laryngeal ventricle containing more than 60 mucous glands that lubricate the larynx.

Glottis

Space/opening between the true vocal folds; important for voicing.

Subglottal atrium

Region below the glottis that leads toward the trachea.

Tongue

Muscular structure involved in speech and swallowing; connected anatomically to the hyoid and epiglottis.

Pharynx

Passageway above the larynx; the laryngeal aditus opens into the pharynx.

Trachea

Airway below the larynx; the cricoid cartilage sits directly above it.

Lateral cricoarytenoid (LCA)

Adducts the vocal folds by rotating/rocking the arytenoids medially; closes the glottis.

Transverse arytenoid

Pulls the arytenoid cartilages together; assists vocal-fold adduction.

Oblique arytenoid

Pulls the arytenoids together and assists adduction/medial compression.

Interarytenoids

Collective term for the transverse and oblique arytenoid muscles.

Posterior cricoarytenoid (PCA)

The ONLY abductor of the vocal folds; pulls/rotates the arytenoids outward to open the glottis.

Cricothyroid

Primary tensor of the vocal folds; tilts/rocks the thyroid cartilage relative to the cricoid, stretching the vocal folds and increasing pitch.

Pars recta

Part of the cricothyroid muscle involved in tilting the thyroid cartilage and increasing vocal-fold tension.

Pars oblique

Part of the cricothyroid muscle involved in changing vocal-fold tension.

Thyrovocalis

Medial portion of the thyroarytenoid muscle; contributes to vocal-fold tension and pitch control.

Thyromuscularis

Lateral portion of the thyroarytenoid muscle; relaxes the vocal folds.

Thyroepiglottic

Intrinsic muscle that assists movement of the epiglottis and helps modify/close the laryngeal entrance.

Aryepiglottic

Intrinsic muscle associated with the aryepiglottic folds; assists closure/constriction of the laryngeal entrance.

Suprahyoid muscles

Muscles generally located above the hyoid that elevate the hyoid and can contribute to elevation of the larynx.

Digastric

Elevates the hyoid; has anterior and posterior bellies.

Stylohyoid

Elevates and retracts the hyoid.

Mylohyoid

Elevates and moves the hyoid forward; forms the floor of the oral cavity.

Geniohyoid

Elevates and moves the hyoid forward.

Hyoglossus

Connects the hyoid to the tongue and contributes to hyoid movement.

Genioglossus

Primarily a tongue muscle; can contribute to elevation of the hyoid.

Inferior pharyngeal constrictor

Pharyngeal muscle that contributes to pharyngeal constriction during swallowing.

Infrahyoid muscles

Muscles generally located below the hyoid that generally depress the hyoid/larynx.

Sternohyoid

Depresses the hyoid.

Omohyoid

Depresses the hyoid and larynx.

Sternothyroid

Depresses the thyroid cartilage.

Thyrohyoid

Can depress the hyoid or elevate the larynx.

Intrinsic laryngeal muscles

Attach laryngeal cartilage to laryngeal cartilage and directly control vocal-fold movement.

Extrinsic laryngeal muscles

Attach the larynx/hyoid to structures outside the larynx and primarily move or stabilize the larynx.

Adduction

Movement of the vocal folds toward the midline.

Abduction

Movement of the vocal folds away from the midline.

Tensing

Increasing vocal-fold tension, generally increasing vibration frequency and pitch.

Relaxing

Decreasing vocal-fold tension, generally decreasing vibration frequency and pitch.

Protection

Prevents food, liquid, and foreign objects from entering the airway.

Breathing

Abduction of the vocal folds opens the airway and allows airflow.

Phonation

Quasi-periodic vibration of the vocal folds that produces voiced sound.

Thoracic fixation

Closing the vocal folds helps stabilize the thorax during activities requiring force, such as lifting.

Swallowing

The larynx helps protect the airway during swallowing.

Coughing

Protective reflex that helps remove foreign material from the airway.

Phonation

Quasi-periodic vibration of the vocal folds that produces voiced sound.

Voicing

Sound produced when the vocal folds vibrate.

Aerodynamic-myoelastic theory

Theory that vocal-fold vibration results from the interaction of airflow/subglottal pressure with the elastic properties and muscular characteristics of the vocal folds.

Myoelastic

Refers to the elastic and muscular properties of the vocal-fold tissue.

Aerodynamic

Refers to airflow and pressure involved in vocal-fold vibration.

Bernoulli effect

When airflow passes through a constriction, velocity increases and pressure decreases.

Subglottal pressure

Air pressure below the vocal folds that helps push them apart during phonation.

Glottal airflow

Airflow passing through the glottis between the vocal folds.

3-5 cm H₂O

Approximate minimum subglottal pressure needed to sustain modal phonation.

Cover-body theory

Theory describing the vocal folds as layered structures in which the outer cover is more flexible and the deeper body provides greater support and muscular control.

Cover

The more flexible outer layers of the vocal fold, especially the epithelium and superficial lamina propria.

Body

The deeper portions of the vocal fold, including deeper lamina propria and thyroarytenoid muscle.

Neurochronaxic theory

Historical theory proposing that the nervous system actively controls each individual cycle of vocal-fold vibration.

Modern view

Vocal-fold vibration is primarily explained by the myoelastic-aerodynamic interaction rather than the nervous system actively opening and closing the folds during every cycle.

Phonatory cycle

One complete cycle of vocal-fold opening, closing, and return to the starting position.

Open phase

Part of the cycle when the vocal folds are separated and airflow passes through the glottis.

Closed phase

Part of the cycle when the vocal folds are in contact or nearly in contact.

Subglottal pressure buildup

Pressure below the vocal folds increases until it is sufficient to push them apart.