Larynx Flashcards
Where does the majority of the thyroid gland sit in proportion to the larynx
Either side and inferiorly
Describe the composition of the larynx
Nine cartilages connected by membranes and ligaments and containing the vocal folds
What level is the larynx located
At the level of the bodies of C3-C6 vertebra
What are the functions of the larynx
- Voice production
2. Guard the air passages, especially during swallowing (most vital)
What are the main supporting parts of the larynx composed of
Hyaline cartilage (tiny synovial joints between them)
Name the 4 different cartilages of the laryngeal skeleton
- Thyroid (largest)
- Cricoid (signet ring)
- Arytenoid (pyramidal)
- Epiglottic (elastic)
What forms the laryngeal prominence
The inferior 2/3rd of the thyroid cartilage’s laminae fuse anteriorly in the median plane
At what level does the superior border of the thyroid cartilage sit
Opposite the C4 vertebra
What is the function of the thyrohyoid membrane
It attaches the thyroid cartilage to the hyoid bone
What does the thyroid cartilage articulate with inferiorly
Cricoid cartilage
Describe the appearance of the cricoid cartilage
Signet ring shape, with the thin band of the ring facing anteriorly, and the signet gemstone facing posteriorly
What does the cricoid cartilage articulate with
Superiorly = Thyroid Inferiorly = Arytenoid
How is the trachea attached to the cricoid cartilage
Via the cricotracheal ligament
What do the arytenoid cartilages articulate with
Lateral parts of the cricoid cartilage lamina
What attach to the muscular processes of the arytenoid cartilages
- Posterior cricoarytenoid muscle
- Lateral cricoarytenoid muscle
These muscles move the vocal folds
What attach to the vocal processes of the arytenoid cartilages
The vocal folds
Name the tiny pieces of cartilage that support the aryepiglottic folds
- Corniculate (attach aryepiglottic fold)
2. Cuneiform (within aryepiglottic folds)
What is epiglottic cartilage composed of
Elastic cartilage, unlike the others which are composed of hyaline cartilage
What connects the epiglottis to the arytenoid cartilages
The aryepiglottic folds
What part of the epiglottis is reflected onto the posterior surface of the tongue
The mucous membrane covering the epiglottis:
- Median glossoepiglottic fold
- Lateral pharyngoepiglottic fold
Where does the quadrangular ligament pass from, and to
Between the arytenoid cartilages and the epiglottis
What forms the false (or vestibular) vocal fold
The quadrangular ligament folds over itself close to the arytenoid cartilages to form a thickened free edge
What forms the true vocal fold (the vocal ligament)
Membrane passing between the cricoid, thyroid, and arytenoid cartilages; the upper border folds to form a free edge (the vocal ligament)
What is the rima glottidis
The most posterior space between the vocal folds
What does each vocal fold contain
Vocal ligament = thickened elastic tissue
Vocalis muscle = fine muscle fibres immediately lateral to the vocal ligaments
What produces phonation
Change in airflow through the larynx
How are individual sounds and words created
Movements of the lips, cheeks, and tongue
What arteries supply the larynx
- Superior laryngeal
2. Inferior laryngeal
Where do the laryngeal arteries branch from
- Superior thyroid (external carotid)
2. Inferior thyroid (subclavian)
Describe the venous drainage of the larynx
The laryngeal veins accompany the laryngeal arteries; they drain into the:
- IJV
- Left brachiocephalic vein
Describe the lymphatic drainage of the larynx superior to the vocal folds
Drain into the superior deep cervical lymph nodes
Describe the lymphatic drainage of the larynx inferior to the vocal folds
Drain into the inferior deep cervical lymph nodes
Describe the actions of the different types of laryngeal muscles
Extrinsic = move the larynx as a whole Intrinsic = move the laryngeal components, altering the length and tension of the vocal fold and the size and shape of the rima glottidis
Name the 6 intrinsic laryngeal muscles
- Cricothyroid
- Thyroarytenoid
- Posterior cricoarytenoid
- Lateral cricoarytenoid
- Oblique arytenoid
- Transverse arytenoid
Describe the innervation to the intrinsic laryngeal muscles
All (except cricothyroid) supplied by the recurrent nerve, a branch of the vagus nerve (CN X)
Describe the innervation to the cricothyroid muscle
External laryngeal nerve, one of the two terminal branches of the superior laryngeal nerve
Describe the action of the cricothyroid
Tenses and elongates the vocal folds
Describe the action of the thyroarytenoid
Relaxes the vocal ligament
Describe the action of the posterior cricoarytenoid
Abducts the vocal folds
Describe the action of the lateral cricoarytenoid
Adducts the vocal folds
Describe the actions of the oblique arytenoid
Sphincter of the laryngeal inlet
Describe the action of the transverse arytenoid
Closes the posterior part of the rima glottidis
