H&N 11.1 The larynx Flashcards
What are the main functions of the larynx?
- air conduction for respiration
- swallowing
- phonation
What is the epiglottis?
a leaf shaped cartilaginous structure which changes position to close of the larynx when food passes.
What are the 2 surfaces of the epiglottis?
- the lingual surface-covered in stratified squamous epithelium
- The under side which is covered in respiratory epithelium.
What are the connections of the epiglottis?
- thyroepiglottic ligament connects the glottis to the thryoid cartilage anteriorly
- hyoepiglottis ligament- connects to the hyoid bone anteriorly.
How does the epiglottis close?
Elevation of the hyoid bone during swallowing (due to suprahyoid muscles, pharyngeal muscles etc) causes the flap of the epiglottis to close- moving from a verticle to a horizontal position.
The upper third of the epiglottis then moves below horizontally, to cover the laryngeal inlet.
During swallowing, what is the aim of pulling down the epiglottis?
- prevents aspiration of food
- directs food into piriform fossae
what is the clinical relevance of the piriform fhossae?
They are a common site for things to get stuck (particulalry sharp things)
Damage here leads to the feeling of something being lodged in larynx.
What symptoms would epiglottitis cause?
- sore throat
- fever
- difficulty breathing–>stridor
- drooling
What are the main cartilages of the larynx?
- epiglottis
- thyroid cartilage
- cricoid cartilage
- arytenoid cartilages
Give some features of the thyroid cartilage.
It is the largest cartilage in the larynx.
It is an incomplete ring, it doesn’t cover the posterior larynx
It has superior and infeiror horns for articulation with the hyoid superiorly, and the cricoid inferiorly.
The voice box is found within the thyroid cartilage.
consists of 2 lamina connected in the middle via the laryngeal prominence.
Give some features of the arytenoid cartilages.
They are found between the tyroid and cricoid cartilages.
They rotate on the cricoid to control tension, length and position of the vocal cords, therefore producing sound.
What anatomical structures attach to the thyroid cartilage?
- vocal cords
- epiglottis
Give some features of the cricoid cartilage.
It’s the only full ring of cartilage found within the larynx
larger posteriorly (signet ring shaped)
It is fixed to the trachea (via criotracheal ligament)
It articulates with the thyroid cartilage and the arytenoid cartilages.
Clinically, how can you make use of the full ring of the cricoid cartilage?
If someone needs emergency surgery (no preparation) you can press on the anterior cartilage when they’ve been put to sleep, and this will compress the posterior aspect against the oesophagus, preventing reflux of oesophageal contents, and therefore aspiration.
Name the important membranes of the larynx.
Quadrangular membrane
Cricothyroid membrane
What is the significance of the membranes of the larynx?
They form the vestibular and the vocal cords, therefore are responsible for speach.
Name the important ligaments of the larynx.
- thyroepiglottis
- hyoepiglottis
- thyrohyoid ligament
- cricothyroid ligament
- median cricothyroid ligament
- cricotracheal ligament.
What is another name for the quadrangular membrane?
-arytenoepiglottic membrane
Where would you insert a tracheostomy?
Just below the thyroid and cricoid cartilages, by piercing the cricothyroid ligament.