Flashcards in H&N 11.1 The larynx Deck (48)
What are the main functions of the larynx?
-air conduction for respiration
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?
What are the main cartilages of the larynx?
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?
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.
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.
-median cricothyroid ligament
What is another name for the quadrangular membrane?
Where would you insert a tracheostomy?
Just below the thyroid and cricoid cartilages, by piercing the cricothyroid ligament.
When looking at a view from a laryngoscope, how do you orientate yourself?
-the epiglottis may or may not be visible, if it is, this indicates the anterior side
-The vocal cords come closer together anteriorly.
Where do the vocal folds run from and to?
-from the thyroid cartilage
-To the arytenoid cartilages.
What is the lining of the vocal folds?
Stratified squamous epithelium, non-keratinised.
What are the false vocal cords made of?
The lower border of the quadrangular membrane
What are the true vocal cords made of?
The free upper border of the crico-thyroid membrane.
What is the space between the vocal cords called?
How is the size of the rima Glottidis changed?
By Abducting and adducting the vocal cords,
This is achieved by the actions of the intrinsic laryngeal muscles.
Which muscle is the only muscle to abduct the vocal cords?
Posterior cricoarytenoid muscle
Generally, what nerve innervates the intrinsic laryngeal constrictors?
Recurrent laryngeal nerve (a branch of the vagus)
What is special about the cricothyroid muscle, with regards to other laryngeal constrictors?
It's the only intrinsic laryngeal constrictor to lie outside of the thyroid cartilage.