Anatomy, Physiology, and Neurology of Voice Production

Inhalation

air is drawn into the lungs - lungs expand; diaphragm contracts and flattens; active process

Exhalation

air forced out of the lungs - lungs contract; diaphragm relaxes and moves up; passive process

Hyoid bone

small bone that sits just above the larynx and supports speaking, swallowing, and breathing

Epiglottis

small, leaf-shaped flap of elastic cartilage that sits at the entrance of the larynx and folds backward to seal off the trachea during swallowing

Thyroid cartilage

largest laryngeal cartilage that forms the front and sides of the larynx

Arytenoid cartilages

pari of small, pyramid shaped cartilages in the larynx that anchor the vocal folds and control their movement

Cricoid cartilage

ring-shaped band of cartilage located at the base of the larynx that completely encircles the airway to keep it open

Cuneiform cartilages

two small, paired cartilages located within the larynx that helps support and stiffen the airway entrance

True vocal folds

vibrate to produce sound

False vocal folds

superior to true vocal folds and protect the airway during swallowing and help trap air in the lungs during heavy lifting

Aerodynamic-Myoelastic Theory

subglottal pressurre opens the VFs bottom to top - elasticity + Bernoulli effect pull them closed - VFs snap back together, creating vibration

Bernoulli effect

as air moves faster between the VFs, air pressure decreases, helping pull the VFs back together

Abduction

vocal folds apart, breathing

Adduction

vocal folds together, phonation

Lateral cricoarytenoid

closes the vocal folds to help produce sound and protect the airway

Transverse arytenoid

pulls the arytenoid cartilages together to close the back of the vocal folds

Oblique Arytenoid

pulls the arytenoid cartilages together to close the back of the vocal folds

Posterior cricoarytenoid

paired; only muscle responsible for abducting the vocal folds

Cricothyroid

stretches and tenses the vocal folds to help raise the pitch of the voice

Thyrovocalis

helps fine-tune tension of the vocal folds to alter pitch

Thyromuscularis

relaxes the vocal folds

Intrinsic muscles of the larynx

lateral cricoarytenoid, transverse arytenoid, oblique arytenoid, posterior cricoarytenoid, cricothyroid, thyrovocalis, thyromuscularis

Vocal fold frequency

how many times the vocal folds complete a vibratory cycle per second

Modal

typical conversational voice

Vocal fry

low frequency, pulse-like vibration

Falsetto

higher-pitched, lighter/less complete vocal fold vibration

Oral resonance

sound resonates primarily through the oral cavity

Nasal resonance

sound resonates through the nasal cavity

Articulators

lips, tongue, mandible, hard palate, soft palate, teeth, cheeks

Vagus Nerve (CN X)

provides motor and sensory innervation to the larynx

Superior laryngeal nerve

controls the cricothyroid muscle, changes vocal fold tension

Recurrent laryngeal nerve

controls the other intrinsic laryngeal muscles, controls vocal fold movement