Larynx Flashcards
what is the function of the larynx
what does it connect?
what level is it at in the neck?
A. The larynx serves both a respiratory and voice-producing (phonation) function.
B. Connects pharynx to trachea; thus directing air to respiratory passages.
C. Also acts to prevent passage of food materials into the airways.
D. Located in the neck, anterior to CV3 – CV6.
E. Composed of cartilages, membranes, and muscles which control the rate and amount of air flowing through the larynx; thus altering the pitch, tone, and volume of voice.
what is the laryngeal aditus
superior opening from pharynx
what is the vestibule
area proximal (above) vestibular folds
what are the vestibular folds?
false folds above the true folds
what is the ventricle
between vestibular folds (false) and vocal folds (true)
what is the rima glottidis
how does it relate to the pitch of the voice?
opening between true vocal folds
shape varies depending on position of vocal folds
- Variation in the tension and length of the vocal folds, and width of rima produces changes in pitch of the voice.
what is the glottis
rima glottidis plus vocal folds
what is the infraglottic cavity
distal (below) true vocal folds
what is clinically significant about the cricoid cartilage
A. Cricoid cartilage – landmark for CV6
- Site where carotid artery can be compressed against CV6
- Junction of larynx and trachea
- Junction of pharynx and esophagus
when is a tracheotomy performed?
where are the incisions made?
when there is an obstruction of the upper airway that can be overcome by puncturing the larynx or trachea
- Incision is made between the cricoid cartilage and the first tracheal cartilages.
- Incision can also be made between the cricoid and thyroid cartilages (through the cricothyroid ligament).
how many paired cartilages are there in the neck and how many singe
paired
arytenoid
corniculate
cuneiform
single
thyroid
cricoid
epiglottic
thryoid cartilage
what are the features
lies anterior to CV4/CV5
a. Laminae (2) fuse anteriorly and remain open posteriorly.
b. Superior horn – attached to hyoid bone by lateral thyrohyoid ligament
c. Inferior horn – articulates with cricoid cartilage
d. Laryngeal prominence (Adam’s apple)
e. Superior thyroid notch
f. Oblique line
cricoid cartilage
what 2 other cartilages does it articulate with?
- Lies anterior to CV6
- Features
a. Immobile ring attached via membrane to first tracheal cartilage
b. Anterior arch
c. Posterior lamina
d. Articulates with arytenoid and thyroid cartilages
arytenoid cartilages
location?
features?
what does it attach to
2 of them
- Lie perched atop the posterior portion of the cricoid cartilage
- Features
a. Apex – attaches to aryepiglottic fold
b. Vocal process – attaches to vocal ligament
c. Muscular process – attaches to posterior and lateral cricoarytenoid muscles
epiglottic cartilage
location?
what happens to this during swallowing?
what are its 4 ligaments
- Leaf-shaped, elastic cartilage situated posterior to root of tongue.
- Broad, superior end is free; inferior end is attached to the thyroid cartilage.
- Muscles of the pharynx pull the thyroid cartilage against the epiglottis during swallowing to prevent food from moving into the larynx.
- Ligaments
a. Thyroepiglottic ligament
b. Hyoepiglottic ligament
c. Aryepiglottic ligament
d. Glossoepiglottic ligaments (median and lateral)
corniculate cartilages
2
lie atop the apex of the arytenoid cartilage
cuneiform cartilage
2
lie within the aryepiglottic folds
what are the 4 extrinsic laryngeal ligaments
attach to non-laryngeal cartilages
thyrohyoid membrane
cricotracheal ligament- cricoid to first tracheal cartilage
hyoepiglottic ligament
glossoepiglottic ligament- epiglottis to back of tongue
thyrohyoid membrane
location
what does it attach
what pierces it
a. Attaches hyoid bone to superior border of thyroid cartilage
b. Thickened laterally (lateral thyrohyoid ligament) and medially (median thyrohyoid ligament)
c. Pierced by the internal laryngeal nerve and superior laryngeal artery.
what are the two intrinsic laryngeal ligaments?
quadrangular ligament
cricovocal (conus elasticus) ligament
quadrangular ligament
where does it attach anteriorly
where does it attach posteriorly
what are its “sub” ligaments
a. Attaches anteriorly to the thyroid and epiglottic cartilages
b. Attaches posteriorly to the arytenoid cartilage
c. Forms vestibular ligaments; covered with mucosa = vestibular fold
d. Forms aryepiglottic ligament; covered with mucosa = aryepiglottic fold
vestibular fold is made up of what
what covers the vestibular fold
thw lower part of the quadrangular ligament (vestibular ligament) plus mucosa covering
covered with highly vascularized mucosa–> contains many mucus-secreting glands
aryepiglottic fold is formed from what
superior portion of the quadrangular ligament is the aryepiglottic ligament which when covered with mucosa makes up the aryepiglottic fold
cricovocal (conus elasticus) ligament
attaches inferiorly to what
attaches superiorly to what
what are the three thickened regions
a. Attaches inferiorly to cricoid cartilage.
b. Attaches superiorly to thyroid and arytenoid cartilages.
c. Thickened regions:
1. Median cricothyroid ligament
2. Lateral cricothyroid ligament
3. Vocal ligament – extends from internal surface of thyroid lamina to vocal process of arytenoid; covered with mucosa = vocal fold
what is the vocal fold made up of
mucosa + vocal ligament (upper part of cricovocal membrane) + vocalis muscle
what is the vocal ligament
innermost portion of cricovocal ligament
extends from thyroid cartilage to vocal process of arytenoid cartilage
vocalis muscle
innermost portion of thyroarytenoid muscle
what controls pitch of voice
vocal ligaments changing length/tension
what are the two joints of the larynx
cricothyroid joint
cricoarytenoid joint
cricothyroid joint
articulation b/w what?
what type of movement and joint
what is its function
- Articulation between cricoid cartilage and inferior horn of thyroid cartilage.
- Synovial – mainly gliding movements
- Allows thyroid to glide on cricoid in order change vocal cord length.
cricoarytenoid joint
b/w what?
what type of joint and movement
function
- Articulation between cricoid cartilage and arytenoid cartilage.
- Synovial – mainly gliding and rotational movements (condylar joint)
- Allows arytenoid cartilages to rotate, glide toward one another.
which muscles cause rotation of arytenoid cartilages
posterior cricoarytenoid (abduct) lateral cricoarytenoid (adduct)
which muscles cause gliding f the arytenoids to adduct vocal ligaments
transverse and oblique arytenoids
which muscles rotate the thyroid cartilage on cricothyroid joint to increase and decrease tension on the vocal ligaments?
Cricothyroid muscle (increase) Thyroarytenoid muscle (decrease)
cricothyroid muscle
action
innervation?
tilts thyroid forward to elongate and tighten vocal ligament
Not working then people are monotone
innervated by the external branch of the superior laryngeal n
transverse and oblique arytenoids
adduct arytenoid cartilages
close the laryngeal inlet by approximating the arytenoid cartilages
recurrent laryngeal n.
posterior cricoarytenoid
abduct vocal folds (open rima glottidis)
recurrent laryngeal
lateral cricoarytenoid
adduct vocal folds (to close rima glottidis)
recurrent laryngeal
thyroarytenoid
rotates thyroid cartilage back to shorten and loosen vocal ligament
vocalis muscle
innermost portion of the thyroarytenoid muscle
lateral to the vocal ligament
locally controls vocal ligament, produces minute adjustments or vocal ligament tension and length
what is the innervation of all the muscles of the larynx except the cricothyroid?
recurrent laryngeal n. (inferior laryngeal)
cricothyroid is the external branch of the superior laryngeal n.
what is the origin of the superior laryngeal n.
what are its two divisions
CN X
has internal and external laryngeal nerves
internal larygneal n. off superior laryngeal n.
what does it provide
what does it pierce
a. Pierces thyrohyoid membrane
b. Provides:
1. GVE-P and GVA proximal to true vocal folds (supraglottic region)
2. SVA to epiglottic region of tongue
external larygneal nerve
SVE to cricothyroid
what is the cough reflex
what nerve mediates this reflex
injury to what nerve will disrupt this reflex?
There is a very strong reflex, mediated by CN X, which functions to prevent foreign objects from entering the airways.
When foreign objects (ex: food) enter the larynx, the superior laryngeal nerve is stimulated (GVA) and causes contraction of laryngeal muscles which close the larynx.
Vagus nerve will stimulate a cough in order to force air out of the larynx.
Injury to the superior laryngeal nn will ablate this protective function due to anesthesia of the laryngeal mucosa. Cough reflex – afferent limb is CN X; efferent limb is CN X.
inferior laryngeal nerve
Motor to all other laryngeal
muscles (SVE).
GVA, GVE-P distal to true vocal folds. (infraglottic region)
continuation of recurrent laryngeal nerve
enters larynx by passing inferior to inferior constrictor muscle
what will a superior laryngeal nerve lesion result in?
loss of cough reflex (loss of sensation to supraglottic region)
the cricothyroid m. will also be paralyzed which often causes a monotonous voice
what is the heimlich maneuver purpose
Choking and the Heimlich Maneuver: If a foreign object enters the larynx, above reflex is engaged and the rima glottidis closes tightly. The Heimlich maneuver is used to dislodge the foreign object by increasing intrathoracic pressure.
superior laryngeal nerve block
Superior laryngeal nerve block is administered when inserting an endotracheal tube. The needle is inserted halfway between the hyoid bone and superior border of the thyroid cartilage. The needle pierces the thyrohyoid membrane and anesthetic agent will bath the superior laryngeal n.
what does injury to the recurrent laryngeal nerve look like?
how can this occur?
where does the left recurrent laryngeal nerve course?
right?
unilateral damage?
bilateral damage?
Injury to the recurrent laryngeal nerve can occur with neck or thoracic damage or surgery.
Recall that the left recurrent laryngeal nerve branches in the thorax (aortic aneurysms, tumors, enlarged lymph nodes in the thorax can compress and damage the recurrent laryngeal nerve).
Injury to the nerve will affect the function of the larynx due to the fact that all but one laryngeal muscle are innervated by the recurrent laryngeal nerve.
If damage is unilateral, patient will present with hoarseness;
if bilateral will present with aphonia .
what is the arterial supply to the larynx (3)
- Superior laryngeal artery
a. Branch of superior thyroid artery
b. Pierces thyrohyoid membrane
c. Supplies larynx above true vocal folds - Cricothyroid artery
a. Branch of superior thyroid artery
b. Supplies cricothyroid muscle - Inferior laryngeal artery
a. Branch of inferior thyroid artery
b. Supplies larynx below true vocal folds
what is the venous drainage to the larynx 2
- Superior laryngeal vein → internal jugular vein
2. Inferior laryngeal vein → left brachiocephalic vein
what is the lymphatic drainage of the larynx
A. Proximal (above) true vocal folds → superior deep cervical lymph nodes
B. Distal (below) true vocal folds → inferior deep cervical lymph nodes
