Larynx and Muscles of Larynx

Role of True Vocal Folds

Phonation (voice production), Airway protection, Breathing (Open to allow airflow), Pressure control (Coughing, Child birth)

Role of False vocal folds

Airway protection, Support for true vf, Do not produce voice

Role of arytenoid cartilage

Movement of VF (rotate, tilt, etc), Anchor Point (posterior attachment of VF), Adjust tension of VF

Role of cricoid cartilage

Structural support (support larynx and trach), Muscle attachment (cricoarytenoid and cricothyroid muscles), Facilitates rotation of arytenoids

Role of epiglottis

Airway protection

Role of Thyroid cartilage

Voice modulation (tilts to stretch\/relax VF), Protection (sheilds inner structures including VF), Attachment (anterior attachment for a lot)

Role of glottis

Air passageway, Sound source, Closes for protection

Tissue types of VF

- Mucosa

- Ligament

- Muscle

five layer scheme (histological): Mucosa

Epithelium and Superficial layer of lamina propria (LP).

five layer scheme (histological): Ligament

Intermediate & Deep layer of LP.

five layer scheme (histological): Muscle

Thyroarytenoid muscle

Three layer scheme (functional): Mucosa

COVER

Three layer scheme (functional): Ligament

TRANSITION

Three layer scheme (functional): Muscle

BODY

1. Epithelium (most superficial layer of VF)

THIN AND STIFF

2. Superficial layer of LP (SLLP)

Loose like JELLO

3. Intermediate layer of LP (ILLP)

ELASTIC like a bundle of soft rubber bands

4. Deep layer of LP (DLLP)

FIBROUS like bundle of cotton threads

5. Thyrovocalis muscle (deepest layer of VF)

like a bundle of STIFF RUBBER BANDS

What is the most superficial layer of VF?

Epithelium

3 multiple choice options

What is the deepest layer of LF?

Thyrovocalis muscle

3 multiple choice options

Location of Hyoid bone

- At the top of the larynx just above the thyroid cartilage

- U-shaped bone; supports the tongue and larynx; connects to thyroid cartilage via the thyrohyoid membrane

Location of epiglottis

- Above glottis; attached to thyroid cartilage and hyoid

- Leaf-shaped flap that covers the glottis during swallowing to prevent aspiration

Location of thyroid cartilage

- Below hyoid; above cricoid

- Shield-shaped; forms the Adam’s apple; the largest laryngeal cartilage

Location of cricoid cartilage

- Directly below the thyroid cartilage

- Ring shaped; forms a complete ring. Supports arytenoids on top

Location of Arytenoid cartilages

- Sits on the upper posterior surface of the cricoid cartilage.

- Pyramid-shaped; attach to vocal folds; rotate/glide to open/close vocal cords

location of corniculate cartilage

- Sit on top of each arytenoid cartilage.

- Tiny, horn-shaped cartilages that help with VF movement

location of cuneiform cartilages

- embedded in aryepiglottic folds and lateral to the corniculate cartilages.

- Rod shaped; support soft tissure folds

location of thyrohyoid membrane

- Between hyoid bone and thyroid cartilage

- Fibrous membrane connecting the hyoid bone to the thyroid cartilage

Location of Glottis

- Middle of larynx; includes vocal folds and space between

- Narrowest part of the airway; responsible for phonation

intrinsic muscles of the larynx

- Tensors: cricothyroid

- Relaxers: Lateral thyroarytenoid/ thyromuscularis

- Abductors: Posterior cricoarytenoid

- Adducators: Lateral cricoarytenoid

Interarytenoid

Transverse & oblique

Tensors

cricothyroid

Relaxers

Lateral thyroarytenoid/ thyromuscularis

Abductors (move VF AWAY from eachother)

Posterior cricoarytenoid (PCA)

Adductors (move VF TOWARDS eachother)

Lateral cricoarytenoid

Interarytenoid

Transverse & oblique

Extrinsic muscles of the larynx

- Elevators: Stylohyoid, Digastric, Mylohyoid, Geniohyoid, Hyoglossus

- Depressors: Omohyoid, Sternohyoid, Sterno thyroid

Elevators

Stylohyoid

Digastric (anterior and posterior belly)

Mylohyoid

Geniohyoid

Depressors

Omohyoid, Sternohyoid, sternothyroid

Thyrohyoid