Larynx and Laryngopharynx (ENT 4) Flashcards
What is the larynx?
Voice box
What is the upper border of the larynx?
Epiglottis
What is the lower border of the larynx?
Cricoid cartilage at the level of C6
Where is the larynx in relation to the trachea?
Sits at very top
What does the larynx communicate with?
Opening posteriorly communicates with airways and pharynx
What is the opening between the larynx and airways called?
Laryngeal inlet
What is the role of the laryngeal inlet?
Allows air to get in and out of lower airways
What makes up the laryngeal skeleton?
Most superior = hyoid bone
Thyroid cartilage
Most inferior = cricoid cartilage
What is the Adam’s apple?
Angle of the thyroid cartilage
Where does the cricoid cartilage sit?
On top of trachea
How are the cartilages arranged around the airways?
Wrapped around them
What closes the space between the hyoid bone and thyroid cartilage?
Thyrohyoid membrane
What closes the space between the thyroid cartilage and cricoid cartilage?
Cricothyroid membrane
Is the cricoid cartilage deficient anywhere?
No, entirely closed
Describe the arch of the cricoid cartilage
Short
In midline
Anterior
Describe the lamina of the cricoid cartilage
Tall
In midline
Posterior
Where are the arytenoid cartilages located?
Posterolaterally on cricoid cartilage (on both sides)
What shape is the arytenoid cartilage?
Pyramidal
What is the muscular process on the arytenoid cartilage for?
Attachment of muscles
Where is the muscular process on the arytenoid cartilage?
Laterally
What is the vocal process on the arytenoid cartilage for?
Attachment of vocal ligaments
In what direction does the vocal process on the arytenoid cartilage project?
Inwards
How do the arytenoid cartilages move?
Swivel on axis going through midline of pyramid
Slide towards each other in midline
Why do the arytenoid cartilages move?
To move vocal ligaments
Is the thyroid cartilage deficient anywhere?
Yes, posteriorly
Where is the angle of the thyroid cartilage located?
Anteriorly
Where is the laryngeal inlet in relation to the thyroid cartilage?
Sits in deficiency posteriorly
What does the thyroid cartilage articulate with inferiorly?
Cricoid cartilage
Where does the thyrohyoid membrane attach to the thyroid cartilage>
Horns located superiorly
Where does the epiglottic cartilage take origin from?
Posterior aspect from angle of thyroid cartilage
In what direction does the epiglottic cartilage project?
Upwards from angle of thyroid cartilage
Where is the epiglottic cartilage in relation to the hyoid bone?
Behind and above
Where is the epiglottic cartilage in relation to the tongue?
Just on posterior aspect of tongue
What is the role of the epiglottic cartilage?
Bolus of food pushes cartilage down > closes laryngeal inlet
From where does the vocal ligament take origin?
Arytenoid cartilage posteriorly, one from each
What is the route of the vocal ligaments?
Run together towards midline to just underneath inferior aspect of epiglottic cartilage
What does the epiglottic cartilage and the mucosa overlying it form?
Epiglottis
What is the fold formed by the mucosa above the vocal ligaments called?
Vestibular fold = false vocal cord
What does the vocal ligaments and the overlying mucosa form?
Vocal fold = true vocal cord
What is the role of the vestibular fold?
If something aspirated down larnyx, won’t hit true vocal cord
How is sound by the vocal cords made?
Vocal ligaments adducted > push air past them > vibrate > make sound
How are the vocal cords position to allow breathing?
Abducted
How is the position of the vocal ligaments changed?
Intrinsic muscles of larynx act largely on muscular process of arytenoid cartilages > cartilages swivel and slide > vocal ligaments alter position
What are the intrinsic muscles of the larynx?
Posterior cricoarytenoid Transverse and oblique arytenoids Lateral cricoarytenoid Cricothyroid Thyroarytenoid Vocalis
What are the attachments of the posterior cricoarytenoid?
Muscular process of arytenoid cartilage
Posterior aspect of cricoid cartilage
What is the action of the posterior cricoarytenoid muscle?
Pulls muscular processes together posteriorly > moves vocal ligaments away from each other > abducts vocal ligaments
Which muscle is the only abductor of the vocal ligaments?
Cricoarytenoid
What are the attachments of the transverse and oblique arytenoids?
Run directly between two arytenoid cartilages
What is the action of the transverse and oblique arytenoid muscles?
Pulls arytenoid cartilages together > slide towards each other in midline > contribute to adduction of vocal ligaments and phonation
What are the attachments of the lateral cricoarytenoid?
Lateral aspect of cricoid
Muscular process of arytenoid cartilage
What is the action of the lateral cricoarytenoid?
Pulls muscular processes away from each other > vocal ligaments move towards each other > adducts vocal ligaments, producing sound
What are the attachments of the cricothyroid?
Thyroid cartilage
Anteriorly to cricoid cartilage
What is the action of the cricothyroid?
Pulls thyroid cartilage forward > stretches vocal ligaments > produces higher pitched sounds
What are the attachments of the thyroarytenoid?
Thyroid cartilage
Arytenoid cartilage
What are the attachments of the vocalis?
Runs length of vocal ligament
What is the action of the thyroarytenoid and vocalis?
Together when they contract, make vocal ligaments more lax > produce lower pitched sounds
Where are the nerves supplying the muscles and sensory innervation of the mucosa of the larynx derived from?
Branches of vagus
Which nerve is most superior in the larynx?
Superior laryngeal
What does the external laryngeal nerve do?
Motor innervation to cricothyroid
What does damage to the external laryngeal nerve mean?
Can’t produce high pitched sounds
What does the internal laryngeal nerve do?
Pierces mucosa
Sensory innervation to mucosa above vocal ligaments
What does the recurrent laryngeal nerve do?
Sensory innervation to mucosa below vocal ligament
Motor innervation to intrinsic muscles of larynx except cricothyroid as inferior laryngeal nerve?
Where is the thyroid gland located?
Superficial to cricoid cartilage and thrachea
What is the blood supply of the thyroid gland?
Superior and inferior thyroid arteries
What is the blood supply to the structures deep to the thyroid gland?
Branches of superior and inferior thyroid arteries
Why is establishing an emergency airway through the trachea not a good ide?
Area very vascular > get bleeding into airways
Where should you make an emergency airway?
At cricothyroid membrane
- Less vascular
- Avoid damage to vocal ligaments
Where is the laryngopharynx?
Behind larynx
What closes the laryngeal inlet completely when swallowing a bolus of food?
Bolus partly pushes epiglottis down
Larynx elevates
What structure does fluid spill into during swallowing to avoid the airways?
Around laryngeal inlet into pririform recess
What is the sensory nerve supply of the pharynx?
Branches of glossopharyngeal nerve
Which nerve reinforces sensory innervation in the nasopharynx?
Branches of trigeminal nerve
Which nerve reinforces sensory innervation in the laryngopharynx?
Branches of vagus nerve
What forms the afferent half of the gag reflex?
Glossopharyngeal nerve
What is the motor nerve supply of the pharynx?
Branches of vagus, except for stylopharyngeus
What is the motor nerve supply to the stylopharyngeus?
Glossopharyngeal nerve
What forms the efferent half of the gag reflex?
Vagus nerve
