The Larynx Flashcards
What encloses the larynx?
Visceral layer of pre trachea fascia in the neck
What structures are contained within the pre tracheal fascia of the neck?
Larynx Strap muscles Thyroid gland Trachea Oesophagus Pharynx Recurrent laryngeal nerves
What lies anterior to the visceral pre tracheal fascia of the neck?
Thin muscular layer
What is the function of the strap muscles?
Accessory muscles of berating
Where is the larynx located in relation to: laryngopharynx, carotid sheath structures and vertebrae?
Anterior to laryngopharynx
Between carotid sheath structures
Between C4-C6 vertebral levels
How does the body normally try to prevent aspiration pf material into the respiratory tract?
Raising of the larynx towards the oesophagus
Cough reflex if aspiration does occur
What is the skeleton of the larynx composed of?
Cartilages suspended from the hyoid bone
What is the function of the cartilages of the larynx?
Maintaining potency of URT
Preventing entry of foreign bodies into LRT
Vocal cords/cough reflex to produce sound
What are the three protrusions of the thyroid cartilage?
Laryngeal prominence (Adam’s apple)
Superior horn
Inferior horn
What shape is the cricoid cartilage?
Full ring shape
What shape is the tracheal cartilage?
C shaped ring (muscle bridges)
Where is the cricothyroid joint?
Between inferior horn of thyroid cartilage and cricoid cartilage
Where is the cricoaretynoid joint?
Between the muscular process of the cretinoid cartilage and the cricoid cartilage
What are the processes of the aretynoid cartilage?
Vocal process (anterior) Muscular process (posterior)
What are the features of the larynx (superior to inferior)?
Laryngeal inlet (aditus) Laryngeal vestibule Saccules False vocal cord (vestibular fold) Laryngeal ventricle True vocal cord (Vocal fold) Infra-glottic cavity
What is the function of the saccule in the laryngeal vestibule?
Produce mucous to lubricate the vocal cords
What is the difference between a vocal ford and a vocal fold?
Vocal fold = Vocal cord covered in mucosa
i.e. on a model, you SEE the vocal fold
What are the vocal cords made of?
Connective tissue
What are the attachments of the true vocal cords?
Vocal process of arytenoid cartilage to thyroid cartilage
What are the attachments of the false vocal cords?
Arytenoid cartilage to epiglottis
Where is the quadrangular membrane?
Between vestibular ligament and epiglottis
Where is the conus elasticus?
Between cricoid and vocal ligament
Where is the laryngoscope placed?
Vallecula
Space between epiglottis and tongue
What is the glottis?
True vocal cords PLUS space in between
What is the Rima Glottidis?
Space between the vocal cords
What is the aryepiglottic fold?
Superior border of quadrangular membrane
What is the innervation of the intrinsic muscles of the larynx?
CN X
All supplied by inferior laryngeal nerve
Exception: Cricothyroid = external laryngeal nerve
What are the intrinsic muscles of the larynx?
Cricothyroid muscles Thyroarytenoid muslces Lateral crico-arytenoid muscles Arytenoid muscles Posterior crico-arytenoid muscles
What is the function of the cricothyroid muscles?
Tense vocal ligament
Nods thyroid cartilage
Increases pitch of voice
What are the attachments of the cricothyroid muscles?
Anterolateral cricoid cartilage to inferior horn of thyroid cartilage
What is the function of the thyroarytenoid muscles?
Relax vocal ligament
Decreases pitch
What are the attachments of the thyroarytenoid muscles?
Posterior thyroid to anterior arytenoid cartilage
What is the function of the lateral crico-arytenoid muscles?
Adducts/brings vocal ligaments together
Makes voice quieter
What are the attachments of the lateral crico-arytenoid muscles?
Muscular process of the arytenoid to anterior cricoid cartilage
What is the function of the arytenoid muscles?
Adducts/brings vocal ligaments together
Makes voice quite by closing rima glottidis
What are the attachments of the arytenoid muscles?
One arytenoid cartilage to another arytenoid cartilage
What are the components of the arytenoid muscles?
Oblique band
Transverse band
What is the function of the posterior crico-arytenoid muscles?
Abducts vocal cords
Makes voice louder by opening rima glottidis
What are the attachments of the posterior crico-arytenoid muscles?
Posterior cricoid cartilage to muscular process of arytenoid cartilage
What is phonation?
Producing a sound in the larynx
What is articulation?
Producing a recognisable sound within the oral or nasal cavities
How are oral sounds created?
Soft palate tenses (CN V3) and elevates (CN X) to close off entrance to nasopharynx
Air directed through oral cavity
Tongue (CN XII) and teeth/lips (CN VII) produce most vowels and consonants
How are nasal sounds created
Soft palate tenses (CN V3) and descends (CN X) to close off entrance to oropharynx
Air directed through nasal cavities
Produces “m”, “n” or “ing” depending on tongue (CN XII) and teeth/lips (CN VII) position
What is the sensory innervation of the mucosa in the larynx above the folds?
Internal laryngeal nerve
What is the sensory innervation of the mucosa in the larynx below the folds
Inferior laryngeal nerve
How do you clinically test vagus supply to the pharynx?
Ask patient to swallow small sip of water
Watch larynx move up and down
Do they splutter?
Hw do you clinically test vagus supply to the larynx?
Listen to patient speak
Are they hoarse?
Ask patient to cough
Is this normal and powerful?
