Larynx Flashcards
What are the functions of the larynx?
Prevent food/fluid entering airway
Ventilation
Cough reflex
Production of sound
What is the larynx?
Part of the respiratory system that lies below the hyoid bone
What are the borders of the larynx?
Begins at the laryngeal inlet
Continues as the trachea
What makes up the larynx?
3 single cartilages
- thyroid
- cricoid
- epiglottis
3 paired cartilages
- arytenoid cartilages
- corniculate cartilages
- cuneiform cartilages
Membranes
- thyrohyoid membrane
- cricothyroid membrane
- cricotracheal membrane
- quadrangular membrane
What are the aryepiglottic folds?
Form the margins of the oval inlet - from the epiglottis to arytenoid
What is the quadrangular membrane?
Membrane between the aryepiglottic folds and vestibular ligament
What is the vestibular ligament?
False vocal cord
Free lower border of quadrangular membrane
What is the vocal ligament?
True vocal cord
Upper free border of cricothyroid membrane
Where does the larynx lie in relation to the pharynx?
Anterior to the laryngopharynx
What are the 3 parts of the larynx?
Supraglottis
Glottis
Infraglottis
Where does the supraglottis part lie?
Epiglottis -> vestibular ligament
Where does the glottis part lie?
Vestibular ligament -> vocal ligament
Where does the infraglottis part lie?
Vocal ligament -> trachea
What type of epithelium lines the larynx?
Pseudostratified ciliated columnar epithelium
What are the main actions of the laryngeal muscles?
Alter size and shape of inlet
Alter size/position of vocal cords
Close inlet + cords during swallowing
What do the intrinsic laryngeal muscles do?
Move cartilages of larynx relative to one another - movement of vocal cords
What innervates the laryngeal muscles?
Recurrent laryngeal nerve - branch of CN X
What do the vocal cords do during inspiration/expiration?
Abduct
What innervates the cricothyroid muscle?
External branch of superior laryngeal nerve - branch of CN X
What happens to the vocal cords during a cough?
Vocal cords adducted
Intrathoracic pressure builds
Cords suddenly adducted
How is the pitch of vocal sound determined?
Vocal cord tension
What muscle controls vocal fold tension?
Cricothyroid muscle
What is the action of the cricothyroid muscle?
Tilts thyroid cartilage forward on cricoid increasing tension in vocal cords
What happens in the larynx during swallowing?
Contraction of aryepiglottic muscles - narrows laryngeal inlet + pulls down epiglottis
Elevation of larynx - by pharyngeal muscles
Closure of vocal cords
What are the branches of the vagus nerve supplying the larynx?
Superior laryngeal
Recurrent laryngeal
What does the superior laryngeal nerve supply?
Internal branch
- sensory to supraglottic region
External branch
- motor - to cricothroid muscle
What does the recurrent laryngeal nerve supply
Sensory to subglottic region
Motor to intrinsic muscles
What is the route of the recurrent laryngeal nerve?
Arises from vagus
Right = loops under subclavian artery
Left = loops under arch of aorta
Ascends in trachea-oesophageal groove
What is a sign of a unilateral vocal cord palsy?
Hoarseness of voice
What happens in a unilateral vocal cord palsy?
Paralysed vocal cord assumes a paramedial position
Contralateral side compensates
What happens in a bilateral vocal cord palsy?
Both vocal cords are paralysed and in paramedian position
Narrow glottis
Why is a bilateral vocal cord palsy an emergency?
Airway obstruction - requires emergency surgical airway
What conditions can effect the larynx?
Laryngitis Laryngeal nodules Croup Epiglottitis Laryngeal oedema
What is laryngitis?
Inflammation of the vocal cords
What is croup?
Inflammation of the larynx and trachea due to RSV
What are the symptoms of croup?
Barking cough
Hoarse voice
Stridor
What is epiglottitis?
Life-threatening condition where there is inflammation of the epiglottis
What are the signs of a patient with a compromised upper airway?
Stridor
Raised resp rate
Distress
Hypoxia
