Larynx Week 9 FINISHED Flashcards
How may cartilages make up the larynx? How many are single and how many are paired and what are their names?
9
3 single - thyroid, cricoid, epiglottic
3 paired - arytenoid, corniculate, cuneiform
What vertebral levels in the neck is the larynx found?
C3-C6
What does the larynx help the pharynx to connect with?
The trachea
What are the functions of the larynx?
Connects the pharynx with the trachea
Route for air into the respiratory tract
Provides a patent airway as well as a means for sealing it off temporarily
Guards the air passages especially during swallowing
Production of voice
Which of the laryngeal cartilages is the largest?
Thyroid
What does thyroid mean in greek?
Shield-like
What landmarks are found anteriorly on the thyroid cartilage?
- Inferior 2/3rds of the laminae (Latin - plate) which are found anteriorly fuse = laryngeal prominence (Adam’s apple)
- Above the prominence the laminae form a V shaped notch called the superior thyroid notch
- A small inferior notch, found in the middle of the inferior border of the cartilage
What landmarks are found posteriorly on the thyroid cartilage?
- Laminae project superiorly as the superior horn and inferiorly as the inferior horn
What landmarks are found superiorly on the thyroid cartilage?
- The superior horn and the superior border of the thyroid cartilage attaches to the hyoid bone via the thyrohyoid membrane
- Has a thickened median region = median thyrohyoid ligament
- Laterally = lateral thyrohyoid ligament
What attaches the superior horn and the superior border of the thyroid cartilage to the hyoid bone?
The thyrohyoid membrane
What is the thickened median region of the thyrohyoid membrane?
The median thyrohyoid ligament
What are the thickened lateral regions of the thyrohyoid membrane?
The lateral thyrohyoid ligaments
What is the laryngeal prominence also known as?
The adams apple
What is the V shaped notch above the laryngeal prominence called?
The superior thyroid notch
What do the inferior horns of the thyroid cartilage articulate with?
The inferior horns articulate with the lateral surfaces of the cricoid cartilage at the cricothyroid joints
What shape is the cricoid cartilage?
Signet ring shaped with the ‘band’ facing anteriorly
Compare the thyroid and cricoid cartilages in terms of strength and size
The thyroid is larger but the cricoid is thicker and stronger
What is the cricoid claim to fame?
It is the only complete ring of cartilage to completely encircle any part of the airway
What does the cricoid attach to superiorly and what attaches these structures?
Attaches to the thyroid cartilage by the median cricothyroid ligament
What does the cricoid attach to inferiorly and what attaches these structures?
Attaches to the 1st tracheal ring by the cricotracheal ligament
What shape are the arytenoid cartilages?
They are pairs of 3 sided pyramids
What do the arytenoid cartilage articulate with?
They articulate with the lateral parts of the superior lateral borders of the cricoid cartilage lamina also known as the cricoarytenoid articulation
What are the processes of the arytenoid cartilages?
An apex superiorly, a vocal process anteriorly and a large muscular process that extends from the base laterally
What can be found at the apex of the arytenoid cartilages?
The corniculate cartilages
What does epiglottis translate to in Greek?
Epi - upon
Glottis - vocal apparatus
What shape is the epiglottic cartilage? What is it covered in?
Heart shaped, broad superiorly and tapers inferiorly and is covered in mucus membrane
Where is the epiglottic cartilage found?
At the root of the tongue and the hyoid bone
Is the epiglottic cartilage anterior or posterior to the laryngeal inlet?
Anterior
What does the epiglottic cartilage attach to inferiorly and what attaches these structures?
Attaches to the thyroid cartilage via the thyroepiglottic ligament
What attaches the epiglottic cartilage to the hyoid bone?
The hyoepiglottic ligament
What is the quadrangular membrane?
A sheet of connective tissue that extends between the lateral aspects of the arytenoid and epiglottic cartilage
What forms the aryepiglottic fold? What is it covered in?
The aryepiglottix ligament which is found in the free margin of the quadrangular membrane. It is covered by a mucus membrane.
Where doe the corniculate cartilages attach?
To the apices of the arytenoid cartilages
What other cartilages do the cuneiform cartilages attach to?
None, they do not attach directly to any other cartilages
What does cuneiform mean in latin?
Wedge shaped
What does the corniculate mean in latin?
shaped like a small horn
Where dies the laryngeal cavity extend between?
From the laryngeal inlet to the inferior border of the cricoid cartilage (where the laryngeal cavity becomes continuous with the trachea)
What are the 3 parts f the laryngeal cavity? Where are each of these parts?
The vestibule of the larynx - superior to the vestibular folds
The ventricle of the larynx - between the vestibular folds and the superior vocal cords
The infraglottic cavity - extends between the vocal folds to the inferior border of the cricoid cartilage
Do the vestibular folds play any part in voice production?
No, they are ‘false vocal cords’
What is the function of the vestibular folds?
Protection
What lies between the vestibular folds and the vocal cords?
The ventricle
What lies above the vestibular folds?
The vestibule
Where do the vestibular folds extend between?
Extend between the thyroid and arytenoid cartilages
They are the free inferior edge of the Quadrangular membrane
What do the vestibular folds consist of?
2 thick folds of mucus membrane which enclose the vestibular ligaments
What is the name of the true vocal cords?
The vocal folds
What is the function of the vocal folds?
Controls sound production, are the source of sound from the larynx
They also act as a sphincter when tightly closed, prevent entry of air.
What is the vocal ligament a thickening of?
It is a thickened medial free edge of the lateral cricothyroid ligament
What is the glottis and what does it comprise of?
The vocal apparatus of the larynx, and comprises of the vocal folds and processes
What is the rima glottidis?
The aperture between the vocal folds
What changes the pitch of the voice?
By varying the tension and length of the vocal cords as well as the width of the rima glottidis and breathing
What causes the deepening of voice in post pubescent males
A greater length in the vocal folds
What are the extrinsic muscles of the larynx?
Suprahyoid mm
- mylohyoid
- geniohyoid
- stylohyoid
- digastric
Infrahyoid mm
- sternohyoid
- sternothyroid
- omohyoid
- thyrohyoid
What do the infrahyoid muscles do?
Depress the hyoid bone and larynx
What do the supra hyoid muscles and stylopharyngess muscles do?
Elevate the hyoid and larynx
What nerves supplies all the intrinsic laryngeal muscles? What muscle is the exception?
The Recurrent laryngeal nerve which is a branch of the vagus nerve.
All except the cricothyroid muscle
What are the functional groups of the intrinsic laryngeal muscles?
Adductors and abductors
Sphincters
Tensors and relaxes
What do the intrinsic laryngeal muscle functional group ‘adductors and abductors’ do?
Move the vocal folds to open and close the rima glottidis
What do the intrinsic laryngeal muscle functional group ‘sphincters’ do?
Close laryngeal inlet as a protective mechanism during swallowing
What do the intrinsic laryngeal muscle functional group ‘tensors’ do?
Elongate and tighten the vocal ligaments and this results in raising the pitch of the voice
What do the intrinsic laryngeal muscle functional group ‘relaxers’ do?
Relax the vocal ligaments
Cricothyroid OIAN
Origin – Anterolateral part of cricoid cartilage
Insertion – Inferior margin and inferior horn of thyroid cartilage
Innervation – External laryngeal nerve (CN X)
Action – Stretches and tenses vocal ligament
Thyroarytenoid OIAN
Origin – Lower half of posterior aspect of angle of thyroid laminae and cricothyroid ligament
Insertion – Anteriolateral surface arytenoid surface
Innervation – Inferior laryngeal nerve (CN X)
Action – Relaxes vocal ligament
Posterior crico-arytenoid OIAN
Origin – Posterior surface of lamina of cricoid cartilage
Insertion – Posterior aspect of the muscular process of arytenoid cartilage
Innervation – Inferior laryngeal nerve (CN X)
Action – Abducts vocal cords
Lateral crico-arytenoid OIAN
Origin – Arch of cricoid cartilage
Insertion – Anterior aspect of the muscular process of the ipsilateral arytenoid cartilage
Innervation – Inferior laryngeal nerve (CN X)
Action – Adducts vocal cords
Transverse and oblique arytenoids OIAN
Origin – One arytenoid cartilage
Insertion – Contralateral arytenoid cartilage
Innervation – Inferior laryngeal nerve (CN X)
Action – Adducts arytenoid catilages, closes posterior rima glottidis
Vocalis OIAN
Origin – Lateral surface of the vocal process of arytenoid cartilage
Insertion – Ipsilateral vocal ligament
Innervation – Inferior laryngeal nerve (CN X)
Action – Relaxes posterior vocal ligament while maintaining (or increasing) tension of the anterior part
What is the arterial supply of the larynx?
Laryngeal arteries = superior and inferior laryngeal arteries
Branches of the superior and inferior thyroid arteries respectively
What is the venous drainage of the larynx?
Laryngeal veins accompany the arteries
Superior laryngeal veins join the superior thyroid veins and drain into the IJV
Inferior laryngeal veins joins the inferior thyroid veins and drain into the left brachiocephalic vein
What is the nerve supply for the larynx?
Superior and Inferior laryngeal branches of the vagus nerve
Superior laryngeal nerve divides into 2 terminal branches
> the internal laryngeal nerve (sensory and autonomic) (larger branch)
> the external laryngeal nerve (motor) (supplies cricothyroid)
Inferior laryngeal nerve = recurrent laryngeal
> divides into an anterior and posterior branches
Supplies all the muscles of the larynx except one (cricothyroid)
