Anatomy of the Larynx Flashcards
What are the functions of the Larynx?
Voice box
Sphincter of respiratory tract
Regulates airflow
Protection of aspirated objects
What is the larynx?
A series of cartilages joined by connective tissue and moved by muscles
Where is the larynx found?
Between the pharynx and the trachea
What encloses the larynx?
Pretracheal fascia
What does the pretracheal fascia enclose?
Strap muscles Thyroid gland Trachea and larynx Oesophagus and pharynx Recurrent laryngeal nerves
Where is the larynx in relation to laryngopharynx?
Anterior
Where is the larynx in relation to carotid sheaths?
Between
Where is the larynx in relation to C4-C6?
Between
What reduced the chance of aspiration?
Raising of the larynx towards the oesophagus
What happens if the larynx isnt raised towards the oesophagus?
Cough reflex engages
What is the larynx composed of?
Cartilages suspended from hyoid bone
What is the function of the cartilage?
Maintaining patency of URT
Cartilages help prevent entry of foreign bodies into LRT
Vocal cords and cough reflex produce sound
Which cartilage is the only full ring?
Cricoid cartilage
What connects the arytenoid cartilages and the cricoid cartilage?
Cricoarytenoid joint
What 2 processes are there on the arytenoid cartilages?
Vocal process
Muscular process
How can cricoid pressure allow ventilation?
Press on the cricoid cartilage Lamina of cricoid compresses the oesophagus Presses it against the C6 vertebral body Oesophagus is closed but airway is open Prevents regurgitation/aspiration Allows ventilation
What are some features of the larynx?
Laryngeal vestibule False vocal cord (vestibular fold) Laryngeal ventricle True vocal cord Infra-glottic cavity
What are the vocal cords?
The free borders of mucosa covered connective tissue in the larynx
What are the 2 pairs of vocal cords?
True
False
Where does the true vocal cords attach?
Vocal proceess of arytenoid cartilage to thyroid cartilage
Where are the false vocal cords found?
Arytenoid cartilage to epiglottis
Where is a laryngoscope placed into?
Vallecula
Space between epiglottis and tongue
What is the rima glottidis?
Space between the the true vocal cords
What is the aryepiglottic fold?
Superior border of quadrangular membrane
What are the intrinic muscles of the larynx and what are they supplied by?
All skeletal muscle
CN X
What are the 4 main movements of the vocal cord and what do they do?
Tension - Increase pitch
Relaxation - Decrease pitch
Adduction - Quieter
Abduction - Louder
Which muscles tense the larynx?
Cricothyroid muscles
What does the cricothyroid muscle do?
Tenses vocal ligament
Nods thyroid cartilage
What are the attachments of the cricothyroid muscles?
Anterolateral cricoid cartilage
Inferior horn of thyroid cartilage
What muscles are the relaxors of the larynx?
Thyroarytenoid muscles
Where do the thyroarytenoid muscles attach?
Posterior thyroid to anterior arytenoid
What are the adductors of the larynx?
Lateral crico-arytenoid
muscles
Arytenoid muscles
Where do the lateral crcio-arytenoid muscles attach?
Muscular process of the arytenoid to anterior cricoid cartilage
How do the arytenoid muscles quieten the voice?
Closes the rima glottidis
Where do the arytenoid muscles attach?
One arytenoid cartilage to another
What muscle abducts the larynx?
Posterior crico-arytenoid muscles
Where do the posterior crico-arytenoid muscles attahc?
Posterior cricoid cartilage to muscular process of arytenoid cartilage
Where do supraglottis tumours drain?
To superior deep cervical nodes
Where do glottic tumours present?
On the cords
What do glottic tumours present with?
Voice changes/airway obstruction
Where do sub-glottic tumours spread to?
Paratracheal nodes
What do sub-glottic tumours present with?
Voice/airway obstruction
What muscles are used in inspiration?
Diaphragm
Intercostal muscles
What muscles are involved in controlled expiration?
Contraction of anterolateral abdominal wall and inspiratory intercostal muscles
What is phonation?
Producing a sound in the larynx
How is phonation brought about?
Once subglottal pressure threshold is reached then air crosses vocal cords causing vibration
What dictates pitch of sound?
Length/tension of vocal cords
What amplifies the buzz made by the larynx?
Pharynx
Oral and nasal cavities
How are oral sounds made?
Soft palate tenses (Cn V3) and elevates (CN X) to close off enterance into nasopharynx
Directs stream of air through oral cavity
Sound is interrupted by tongue (CN XII) and the teeth/lips (CN VII) to produce most vowels
Nasal sounds
Soft palate tenses (CN V£) and descends (CN X) to close off enterance into oropharynx
Directs stream of air through nose
What supplies all intrinsic muscles apart from cricothyroid?
Inferior laryngeal nerve
What supplies mucosa above the folds?
Internal laryngeal nerve
What supplies the mucose below the folds?
Inferior laryngeal nerve
What supplies motor to cricothyroid?
External laryngeal
How can the vagus nerve be clinically testeed?
Pharynx - ask to swallow sip of water (watch larynx move up and down, do they splutter)
Larynx - listen to patient speak (Is voice hoarse, are intrinsic muscles of larynx functioning normally)
Ask patient to cough (is it normal and powerful)
