COMD 3100 Chapter 3

Secondary Function of the Larynx

Allows for holding of breath, heavy lifting, and childbirth.

Thyroid Cartilage

Articulates inferiorly with cricoid cartilage. Largest laryngeal cartilage. Located at the superior end of the trachea.

Cricoid Cartilage

Attaches to the trachea. Arch provides clearance for vocal folds. Lamina provides point of articulation for arytenoid cartilages.

Intrinsic Laryngeal Musculature

Both origin and insertion on laryngeal cartilages. Responsible for opening, closing, and relaxing the vocal folds. Adductors, abductors, tensors, and relaxers.

Vestibule

Cavity between the aditus and the ventricular false vocal folds.

Framework of the Larynx

Comprised of three paired cartilages and three unpaired.

Thyroepiglottic Ligament

Connects epiglottis to the interior portion of the thyroid cartilage, near the thyroid notch.

Cricotracheal Ligament

Connects lower border of cricoid cartilage with upper border of first tracheal ring.

Cartilages of the Larynx

Cricoid Cartilage (unpaired) Thyroid Cartilage (unpaired) Arytenoid Cartilage (paired) Corniculate Cartilages (paired) Epiglottis (unpaired) Cuniform Cartilages (paired)

The Laryngeal Cavity

Cross Sectional Cut

Elevators

Digastricus, Stylohyoid, Mylohoid, geniohyoid, Hyoglossus, and Inferior Pharyngeal Constrictor

Lower Conus Elasticus

Elastic portion of the larynx that connects the thyroid, cricoid, and arytenoid cartilages.

Triticial Cartilage

Embedded in the lateral hyothroid ligament.

Aditus

Entrance of the Larynx.

Vocal Fold Structure

Five Layers: • Epithelium • Superficial Lamina Propria • Intermediate Lamina Propria • Deep Lamina Propria • Thyroarytenoid Muscle

Thyrohyoid (Hyothroid) Membrane

Found between hyoid bone and superior portion of thyroid cartilage. Membrane thickens medially and laterally.

Bernoulli Principle

Given a constant volume flow of air or fluid, a a point of constriction there will be a decrease in air pressure and an increase in velocity of flow.

Lesser Cornu

Hyoid Bone: junction of the corpus and greater cornu.

Corpus

Hyoid Bone: point of attachment for 6 muscles.

Greater Cornu

Hyoid Bone: projects posteriorly.

Cricopharyngeus

Inferior pharyngeal constrictor Sphincter muscle at the orifice of the esophagus Action: contraction of muscle promotes elevation of the larynx while constricting pharynx (same as thyropharyngeus)

Thyropharyngeus

Inferior pharyngeal constrictor Involved in propelling food through the pharynx Action: contraction of muscle promotes elevation of the larynx while constricting pharynx

Base

Inferior portion of the arytenoid that articulates with the cricoid.

Cricothyroid Pars Oblique

Inserts at the juncture of the thyroid laminae and inferior horns.

Cricothyroid Pare Recta

Inserts into the lower surface of the thyroid lamina.

Cricoarytenoid Joint

Junction between the cricoid and arytenoid cartilage. Allows for rocking, gliding, and minimal rotation. Assists in approximation and abduction of the vocal folds which produces voice.

Cricothyroid Joint

Junction of the cricoid cartilage and inferior cornu of the thyroid cartilage. Allows for thyroid cartilage to rock down in front and allows the thyroid to glide forward and backward in relation to the cricoid. Allows for major adjustments in vocal pitch.

Muscular Process

Lateral portion of the arytenoid. Attachment for muscles that adduct and abduct the vocal folds.

Oblique Line

Lateral superficial aspect of the thyroid laminae.

Thyromuscularis / Muscularis

Lateral to each thyrovocalis. Origin: inner surface of thyroid cartilage near notch and lateral to the thyrovocalis. Insertion: arytenoid cartilage at the muscular process and base.

Vocal Process

Lower portions of the arytenoid that project toward the thyroid notch. Vocal fold attachment.

Thyrovocalis / Vocalis

Medial muscle of the vocal folds. Origin: inner surface of the thyroid cartilage near the thyroid notch. Insertion: lateral surface of the arytenoid vocal process.

Sternohyoid

Origin: posterior-superior region of manubrium sterni and medial end of clavicle. Insertion: inferior margin of the hyoid corpus. Action: depresses the hyoid.

Lateral Cricoarytenoid Muscle

Origin: superior-lateral surface of cricoid cartilage. Insertion: muscular process of the arytenoid muscle.

Valleculae

Pair of small indentations between the root of the tongue and the epiglottis.

Arytenoid Cartilages

Paired cartilage that articulates with the lamina of the cricoid cartilage. Forms posterior point of attachment for vocal folds. Allows for onset and offset voicing. Pyramidal in shape.

Corniculate Cartilages

Paired cartilage that rides on the superior surface of each arytenoid.

Inferior Cornua

Project downward to articulate with cricoid cartilage.

Superior Cornua

Project upward to articulate with hyoid bone.

Primary Function of the Larynx

Protect the airway from foreign objects.

Tracheostoma

Put in place after a laryngectomy to allow for breathing.

Relaxers

Relax muscles.

Intrinsic Abductors

Responsible for pulling the vocal folds apart.

Tensors

Responsible for tightening the muscles.

Aryepiglottic Folds

Run from the side of the epiglottis to the arytenoid apex-forms upper margin of quadrangular membrane.

Pyriform Sinues

Small fossae (indentations) between aryepiglottic folds medially and the mucous lining of the thyroid cartilage.

Cuneiform Cartilages

Small, paired cartilages embedded in the aryepiglottic folds. Cause a small bulge on the surfae of the membrans. Provide support for membranous laryngeal covering.

Posterior Cricoarytenoid

Sole abductor of the vocal folds. Origin: posterior cricoid lamina. Insertion: posterior aspect of the muscular process of the arytenoid cartilages.

Laryngeal Ventricle

Space between margins of false vocal folds and true vocal folds.

Glottis

Space between the vocal folds inferior to the ventricle and superior to the conus elasticus. Most important laryngeal space for speech. Area is variable depending on the configuration of the vocal folds.

Oblique Arytenoid

Superficial to transverse arytenoid. X configuration. Origin: posterior base of the muscular process of arytenoid. Insertion: apex of the opposite arytenoid.

Thyroid Notch

Superior most point of thyroid angle.

Apex

Superior portion of the arytenoid.

Laryngectomy

Surgical removal of the larynx. Oral cavity is sealed off from the trachea and lower respiratory passageways. Inability to produce sound.

Thyroeppiglottic Ligament

The epiglottis attaches to the thyroid via the ____________.

Adduction

The process of bringing the vocal folds together for phonation.

Laryngeal Membranes and Ligaments

Thyrohyoid membrane Upper quadrangular membranes Aryepiglottic folds Lower conus elasticus Vocal ligament Cricotracheal Ligament Thyroepiglottic Ligament

Thyroid Laminae

Two anterior plates that join at the thyroid angle.

Thyroarytenoid Muscle

Two parts - tyrovocalis and thryromuscularis

Upper Quadrangular Membranes

Underlying quadrangular membranes that create a layer of connective tissue that runs from arytenoids to the epiglottis and thyroid cartilage. Forms false vocal folds.

Hyoid Bone

Unpaired bone that articulates with the superior cornu of the thyroid cartilages. Only bone in the body that is not attached to another bone.

Epiglottis

Unpaired leaf-shaped cartilage. Arises from the inner surface of the angle of the thyroid cartilage just below the notch.

Transverse Arytenoid Muscle

Unpaired. Origin: lateral margin of the posterior surface of one arytenoid. Insertion: corresponding surface of the other arytenoid.

Vocal Ligament

Upper portion of the conus elasticus. The upper portion becomes the vocal folds.

Phonation

Vibration of the vocal folds which produces speech voicing.

Thyroid Angle

Where the thyroid laminae join.

Intrinsic Adductors

responsible for bringing the vocal folds together (=voicing). Lateral cricoarytenoid, transverse arytenoid, and oblique arytenoid.

Abduction

the process of drawing the vocal folds apart to terminate phonation.

Extrinsic Laryngeal Musculature

• One attachment on a laryngeal cartilage and the other attachment on a non-laryngeal structure • Responsible for major adjustments of the larynx • Depressors of the Larynx • Elevators of the Larynx

Hyoglossus

• Origin: greater cornu of hyoid bone • Insertion: sides of the tongue • Action: hyoid elevator or lingual depressor

Digastricus Anterior

• Origin: inner surface of mandible • Insertion: joins posterior digastricus by means of intermediate tendon • Action: draws hyoid up and forward

Genioglossus

• Origin: inner surface of the mandible • Insertion: anterior surface of the hyoid corpus • Action: hyoid elevator

Sternothyroid

• Origin: manubrium sterni and first costal cartilage • Insertion: oblique line of the thyroid cartilage • Action: depresses the thyroid cartilage

Digastricus Posterior

• Origin: mastoid process of the temporal bone (behind ear) • Insertion: hyoid bone • Action: draws hyoid up and back

Geniohyoid

• Origin: mental spines of the mandible • Insertion: hyoid bone at the corpus • Action: elevates hyoid and draws it forward

Stylohyoid

• Origin: styloid process of the temporal bone • Insertion: corpus of hyoid bone • Action: elevates and retracts the hyoid bone

Mylohyoid

• Origin: underside of the mandible (near mylohyoid line) • Insertion: corpus of hyoid bone • Action: elevates hyoid and projects it forward or depresses the mandible

Omohyoid Inferior Belly

• Originates on the upper border of the scapula • Joins at intermediate tendon with the superior belly • Action: depresses hyoid and larynx

Depressors

• Sternohyoid • Omohyoid • Sternothyroid • Thyrohyoid

Lamina Propia

• Superficial Lamina Propria (highly elastic) • Intermediate Lamina Propria (elastin fibers) • Deep Lamina Propria (collagen fibers)

Omohyoid Superior Belly

• Terminates on the side of the hyoid corpus • Joins at intermediate tendon with the inferior belly • Action: depresses hyoid and larynx