Larynx Flashcards
What is the primary function of the larynx?
To act as a valve to prevent airway obstruction and protect the lower airway
What vertebral levels does the larynx span?
C4-C6
What structure marks the inferior end of the larynx?
Inferior margin of cricoid cartilage as it becomes trachea
Which region of the larynx are the vestibular folds in?
supraglottic, transglottic, infraglottic
transglottic.
The supraglottic space extends from the laryngeal inlet to the vestibular folds, but does not include them.
What marks the superior boundary of the infraglottic space?
the inferior margin of the vocal folds (the vocal folds themselves are in the transglottic space)
Where does innervation of the larynx above the vocal folds come from?
internal branch of superior laryngeal nerve off vagus
Where does innervation of the larynx below the vocal folds come from?
inferior laryngeal nerve, a branch of the recurrent laryngeal nerve off vagus
Contraction of the cricothyroid muscles would lead to what change in vocal pitch?
What nerve innervates these muscles?
Contraction of the cricothyroid muscles tilts the thyroid cartilage anteriorly and inferiorly, tightening and lengthening the vocal cords, generating a higher pitch
external branch of superior laryngeal nerve off vagus
What action do the lateral cricoarytenoid muscles have on the vocal cords?
They adduct them
What is the main action of the posterior cricoarytenoid muscles?
abduction of the vocal cords
What muscle is the primary antagonist of the cricothyroid muscles?
the thyroarytenoid muscles. It’s main function is to bring the thyroid cartilage closer to the arytenoids, shortening the vocal cords, generating a deeper pitch.
Also possibly vocalis
What is the rima glottidis?
The space between the opening of the true vocal cords and the arytenoid cartilage
What does the quadrangular membrane connect?
epiglottis to the vestibular ligament
What does the conus elasticus connect?
vocal ligament and the cricoid cartilage
What ligament lines the inferior margin of the true vocal cords? What does it connect to inferiorly
conus elasticus.
Inferiorly connects to cricoid cartilage
What is the rima vestibuli?
space between the vestibular ligaments
What CN predominantly innervates the larynx?
Vagus CN X
Does the transverse arytenoid muscle adduct or abduct the vocal cords?
It spans the gap between the two arytenoids, adducting them when it contracts, closing the rima glottidis
What structures pass between the inferior and middle constrictors to the larynx?
Internal branch of Superior laryngeal n, superior laryngeal a. and v.
What connects the thyroid cartilage to the cricoid along the midline of the body? What is this ligament called as it continues laterally and posteriorly?
median cricothyroid ligament.
Conus elasticus
Where are the laryngeal saccules located with respect to the ventricles? What is their function?
They are the anterosuperior continuation of the laryngeal ventricles. They house many secretory cells that create a fluid to lubricate the vocal cords
What innervates the inlet, vestibule, and ventricle/saccule regions of the larynx?
Internal branch of superior laryngeal nerve of CN X (Vagus)
What innervates the infraglottic space?
Inferior laryngeal nerve of CN X (Vagus)
What is the origin/insertion of the cricothyroid muscle?
origin: anterior and lateral aspects of arch of cricoid cartilage
Insert: inferior margin and inferior horn of thyroid cartilage
What innervates the cricothyroid muscle?
external branch of superior laryngeal nerve (CNX)
What are the actions of the cricothyroid muscle?
stretches vocal fold; increases pitch of voice
What are the origin/insertion of the posterior cricoarytenoid muscles?
origin: posterior surface of lamina of cricoid cartilage
insert: muscular process of arytenoid cartilage
What innervates all muscles of the larynx except the cricothyroid?
inferior laryngeal nerve (CNX)
What is the origin/insertion of the lateral cricoarytenoid?
origin: superior border of arch of circoid cartilage
insert: muscular process of arytenoid cartilage
What are the actions of the lateral cricoarytenoid musucles?
adducts vocal fold; closes airway partially or completely depending on actions of other muscles
What are the origin/insertion of the thyroarytenoid muscles?
origin: posterior surface of thyroid cartilage at midline
insert: anterolateral border of vocal process of arytenoid cartilage
What are the actions of the thyroarytenoid muscles?
relaxes vocal fold; lowers pitch of voice
What are the origin/insertion of the transverse and oblique arytenoid muscles?
origin: one arytenoid cartilage
insert: on the other arytenoid cartilage
What are the actions of the transverse and oblique arytenoid muscles?
closes intercartilaginous portion of rima glottidis; important for couging
What are the origin/insertion of the vocalis muscles?
origin: vocal process of arytenoid cartilage
insert: vocal ligaments
What are the actions of the vocalis muscles?
fine tunes tension of vocal ligaments; affects the pitch of voice.
What functions does the internal branch of the superior laryngeal nerve have?
provides both sensory and parasympathetic innervation to the mucosa and glands of the base of the tongue, the anterior and posterior epiglottic fold, the laryngeal inlet and the vestibule as far down as the vocal folds. Has SA for taste at base of tongue.
When is the recurrent laryngeal nerve renamed inferior laryngeal nerve?
When it passes the cricothyroid joint
What types of nerve fibers run in the inferior laryngeal nerve?
BE - all the intrinsic laryngeal muscles except cricothyroid
GSA - sensation for infraglottic space
GVE - to glands below the vocal cords
