Module 4: Phonation

What is the only bone associated with the larynx?

The hyoid bone.

Is the hyoid bone attached to any other bone?

No, it is not directly attached to any other bone in the skeleton.

What are the main parts of the hyoid bone?

The body, greater horns, and lesser horns.

List the main functions of the hyoid bone.

Supports the tongue root, suspends the larynx, and assists with speech, swallowing, and breathing.

Name the three unpaired cartilages of the larynx.

Thyroid, cricoid, epiglottis.

What is the largest cartilage of the larynx?

The thyroid cartilage.

What are the superior and inferior horns of the thyroid cartilage connected to?

Superior horn → hyoid bone (via thyrohyoid membrane); Inferior horn → cricoid cartilage.

What is the common term for the thyroid cartilage prominence?

The Adam’s apple (laryngeal prominence).

Describe the cricoid cartilage.

A complete ring of cartilage sitting below the thyroid and above the trachea; forms the base of the larynx.

What type of cartilage is the epiglottis made of, and what is its function?

Elastic cartilage; it folds backward during swallowing to protect the airway.

List the three paired cartilages of the larynx.

Arytenoid, corniculate, cuneiform.

Where are the arytenoid cartilages located and what do they control?

Sit on top of the cricoid posteriorly; control vocal fold tension and position.

What are the two processes of the arytenoid cartilage?

Muscular process (lateral surface – muscle attachment) and vocal process (anterior surface – vocal fold attachment).

What is the function of the corniculate cartilages?

Support the aryepiglottic folds and stabilize arytenoid movement.

What is the function of the cuneiform cartilages?

Provide structure and support for vocal fold motion and airway stability.

What are the two laryngeal joints?

Cricothyroid joint and cricoarytenoid joint.

What is the primary movement of the cricothyroid joint and its function?

Rotation and gliding; lengthens and tenses vocal folds → controls pitch.

What is the main movement of the cricoarytenoid joint and its function?

Rocking and gliding; abducts/adducts the vocal folds → controls glottal opening and closing.

List the three main layers of the vocal folds.

1) Epithelium 2) Lamina propria 3) Muscle (thyroarytenoid).

What is the function of the epithelial layer?

Protects the underlying tissue.

Describe the three layers of the lamina propria.

Superficial: Loose, few fibers (Reinke’s space).
Intermediate: Many elastic fibers – stretchy.
Deep: Collagen fibers – strong.

What does the vocal ligament consist of?

The intermediate + deep layers of the lamina propria.

What is the primary muscle of the vocal folds and its function?

Thyroarytenoid muscle – shortens and relaxes the folds.

Are the ventricular (false) folds used in phonation?

No, they protect the airway but do not vibrate for voice.

What is the role of the aryepiglottic folds?

Connect epiglottis to arytenoids; close the laryngeal inlet during swallowing.

Where is the laryngeal vestibule located?

Above the ventricular (false) folds.

What is found in the laryngeal ventricle?

Mucus glands that lubricate the vocal folds.

What is the glottis?

The space between the vocal folds that opens and closes during breathing and phonation.

What is the primary function of the intrinsic laryngeal muscles?

Control movement of the vocal folds.

Name the four adductor muscles of the larynx.

Lateral cricoarytenoid, transverse arytenoid, oblique arytenoid, thyroarytenoid.

What is the only abductor muscle of the larynx?

Posterior cricoarytenoid.

Which muscle acts as a tensor to raise pitch?

Cricothyroid.

Which muscle acts as a relaxer to lower pitch?

Thyroarytenoid.

What cranial nerve innervates all intrinsic laryngeal muscles?

Vagus nerve (CN X).

What do the extrinsic laryngeal muscles do?

Attach the larynx to surrounding structures and move it up or down.

Which muscle elevates the larynx by decreasing distance between thyroid & hyoid?

Thyrohyoid.

Which muscle depresses the larynx?

Sternothyroid.

What is the role of the inferior pharyngeal constrictor?

Moves the lower pharyngeal wall inward; aids swallowing and supports the airway.

What is the overall function of the supplemental muscles?

Support and stabilize the larynx in position.

List the suprahyoid muscles and their general function.

Digastric, Geniohyoid, Mylohyoid, Stylohyoid, Hyoglossus, Genioglossus – elevate the larynx and hyoid.

List the infrahyoid muscles and their general function.

Omohyoid, Sternohyoid – depress the hyoid and larynx.

Which muscles adduct the vocal folds?

LCA, TA, Transverse arytenoid, Oblique arytenoid.

Which muscle abducts (opens) the vocal folds?

Posterior cricoarytenoid.

Which muscles change the length of the vocal folds?

Thyroarytenoid (shortens), Cricothyroid (lengthens), Posterior cricoarytenoid (lengthens via abduction), Lateral cricoarytenoid (shortens via adduction).

Name the laryngeal depressor muscles.

Sternothyroid, Omohyoid, Sternohyoid.

Name the laryngeal elevator muscles.

Thyrohyoid, Digastric, Mylohyoid, Geniohyoid, Stylohyoid, Hyoglossus, Genioglossus.