Anat and Phys Phonation

Phonation

Speech production

Comprises the physiologic process of airflow modulation

Occurs within the larynx

Lungs

Power source

Where phonation begins

Trachea

Tube carrying air from lungs to larynx

Larynx

Voice box housing the vocal folds

Located centrally in the anterior portion of the neck below the mandible

Consists of cartilage, muscle, and other connective tissues

Sits beneath the hyoid bone and above the first tracheal ring

Vocal folds

Source of vibration for sound production

Within the glottis- middle of the larynx

Positions horizontally across the larynx

Attached to laryngeal cartilages

Pharynx and oral cavity

Resonating chamber

Shape air

Articulators

Sound modification system - modify sound

Structures of vocal folds

Epithelium, lamina propria, vocalis muscle

Epithelium of vocal folds

Outer most layer

Flexible= easy to vibrate

Essential protection

3 sub layers of lamina propria of vocal folds

Superficial, intermediate, deep

Superficial layer (Reinkes space)

Most flexible part of vocal folds

Major vibrator allowing for oscillation

Intermediate layer

More rigid than superficial but flexible

Essential for controlling vocal pitch

Deep layer

Composed of collagen fibers, stiffest part of the lamina propria

Structural support

Vocalis muscle

Deepest/ inner part of the vocal folds

Bundle of muscle fibers that runs parallel to the vocal ligaments

Thyroid cartilage in the front, arytenoid cartilage in the back

Hyoid bone

Only bone anchoring laryngeal muscles

Located at the base of the tongue above the larynx

Thyroid cartilage

Largest and most prominent

Located at the front of the neck- Adams apple

Inner surface attached to vocal folds at the anterior end

Cricoid cartilage

Ring shaped, inferior to the thyroid cartilage, superior to the trachea

Narrower anterior portion called the arch, broader posterior portion called lamina

Crucial for the tension and positioning of the vocal folds

Arytenoid cartilages

A pair of small pyramid shaped cartilages sitting on the posterior aspect of the cricoid cartilage

Connected to the posterior ends of the vocal folds

Abduction and adduction of the vocal folds

Corniculate cartilages

Small, horn shaped structures sitting on top of the arytenoid cartilages

Cuneiform cartilages

Small rod like cartilages located in the aryepiglottic folds, which run from the arytenoids to the epoglottis

Epiglottis

A leaf shaped cartilage protecting the airway during swallowing

Prevents food or liquid from entering the trachea

Vocal fold muscles

lateral cricoarytenoid, posterior cricoarytenoid, cricothyroid, thyroarytenoid

Lateral cricoarytenoid muscle

Pulls arytenoid cartridges together, adducting (closing) the vocal folds

Posterior cricoarytenoid muscle

Abducts (separates) the vocal folds allowing air to pass freely when we breathe

Cricothyroid muscle

Lengthens and tenses the vocal folds by tilting the thyroid cartilage forward, creating higher pitched sounds

Thyroarytenoid muscle (including vocalis)

Shortens and relaxes the vocal folds to produce lower-picthed sounds

Intrinsic muscles

Cricothyroid, thyroarytenoid, vocalis, posterior cricoarytenoid, lateral cricoarytenoid, transverse arytenoid, oblique arytenoid

Extrinsic muscles

Suprahyoid, infrahyoid

Cricothyroid Muscle

Origin- antrolateral aspect of cricoid cartilage

Insertion- lower boarder of thyroid cartilage

Function- lengthens and tenses vocal cords, increases pitch

Nerve supply- external branch of superior laryngeal

Thyroarytenoid muscle

Origin- inner surface of thyroid cartilage

Insertion- antrolateral surface of arytenoid

Function- Shortens and relaxes vocal cords

Nerve supply- recurrent laryngeal nerve

Vocalis muscle

Origin- inner surface of thyroid

Insertion- vocal process of arytenoid cartilage

Function- fine tunes the tension in the vocal cords

Nerve supply- recurrent laryngeal nerve