Lecture 29: Larynx & Phonation Flashcards
Where does the larynx begin and end?
Starts at top of epiglottis and continues to lower border of cricoid cartilage (C6)
What are the components of the laryngeal skeleton?
Thyroid cartilage, cricoid cartilage, hyoid bone, epiglottic cartilage, arytenoid cartilage
What is the anterior angle that sticks out from the thyroid cartilage?
Adams apple
Where is the thyroid deficient?
Posteriorly - inlet for larynx
What are the features of the structure of the thyroid cartilage?
2 lamina on either side and horns posteriorly
What do the posterior horns of the thyroid cartilage articulate with?
Cricoid cartilage
What is unique about the cricoid cartilage?
Forms a full ring encircling the larynx
What are the structural features of the cricoid cartilage?
Short anterior arch and tall posterior lamina, arytenoid cartilage on each side
What are the features of the arytenoid cartilage?
Two small bumps - cuneiform and cuniculate
Muscular process and vocal process for attachments
How does movement of the arytenoid cartilage affect the vocal ligaments?
Cartilage can move and so when attachments contract it is moved and changes the position of the vocal ligaments.
eg. muscle contracts, pulls arytenoid outwards, vocal process moves inwards and connects ligaments
What is the cricothyroid cartilage important for?
Management of emergency airways
What does the epiglottic cartilage have an attachment to?
Angle of thyroid cartilage posteriorly
Where are the vocal ligaments attached?
Angle of thyroid to arytenoid
What is the quadrangular membrane and what are its thickenings?
Membrane over arytenoid cartilage to epiglottic cartilage.
Inferior free edge thickening - vestibular ligament
Superior free edge thickening - aryepiglottic ligament
What is the vestibular sinus?
Space between thyroid cartilage (lamina) and the vocal ligaments
What is the ventricle?
The space between the folds of mucosa over the cartilages
What are the true vocal cords?
Folds that when adducted produce sound
What are the false vocal cords?
Formed by vestibular folds, don’t produce sounds by form a protective barrier for the underlying vocal cords in case something is aspirated
When are the false vocal cords used?
In cats - used to make purring sound
What happens if something lodges in the ventricle?
Pushes on vocal ligaments - interferes with phonation and causes coughing
What folds have high/low vascularity?
Vocal folds have low vascularity and vestibular folds have high vascularity
What is the rima glottis?
Space where communication occurs - between vocal ligaments
What is the action of posterior cricoarytenoid?
Abducts vocal cords - critical for breathing
What is the role of transverse and oblique arytenoids?
Close rima glottis - help arytenoid cartilage slide together - phonation
What is the role of cricothyroid?
Lengthen vocal cord - produce high pitch sound
What is the role of lateral cricoarytenoid?
Adducts vocal fold - phonation
What is the role of vocals and thyroarytenoid?
Relaxes vocal fold - low pitch sound
What nerve supplies the larynx?
Vagus
What nerve branches does the vagus give off and what do they supply?
Superior laryngeal
- external laryngeal for cricothyroid
- internal laryngeal for sensory to mucosa
Recurrent laryngeal
- inferior laryngeal for intrinsic muscles
What is the blood supply for the larynx?
Superior and inferior thyroid vessels - giving off smaller laryngeal branches
What is stridor?
Extreme effort needed for phonation - ligament not working properly - need lots of effort to pass enough air through to generate vibration
What should be considered in emergency airways procedures?
Cricothyroid membrane puncture over tracheotomy - avoid all of the vessels associated with the trachea
What can intubation be made easier?
Hyperextend head and use hooked tube
