Session 10 Flashcards
What are the functions of the larynx
Airway protection
Ventilation
Phonation
Cough reflex
Anatomical features of the larynx
Suspended from and lies below hyoid bone
Part of the URT
Begins at laryngeal inlet, ends at lower border of cricoid cartilage C6
Continuous as trachea
What are piriform fossae
Spaces within laryngopharynx - deep recesses
Where pharyngeal muscles have wrapped around back of opening of larynx
3 subdivisions of larynx
Supraglottis, glottis, subglottis
Which cartilages form the structural framework of the larynx
Epiglottis, thyroid, cricoid and arytenoid cartilages
Synovial joints between the cartilages allow movement between the
Thyroid and cricothyroid (A)
Cricoid-arytenoid (F)
Larynx is suspended from the hyoid bone via the
Thyrohyoid membrane
2 other important membranes
What does a cricothyroidotomy do
Provides emergency access to airway, beneath vocal cords
What are aryepiglottic folds
The borders of the membranes create
The sides of the epiglottis are connected to the arytenoids by the
Aryepiglottic folds
What forms the aditus or entrance of the larynx
Epiglottis along with aryepiglottic folds
Describe thyroid cartilage
Shield like
2 lateral plates form laryngeal prominence
Describe cricoid cartilage
Signet ring shpaed, only complete ring of cartilage throughout respiratory Tract
Attached to trachea inferiorly by the cricotracheal membrane
Arytenoids sit on top, one either side
Space in the middle between the true vocal cords is the
Rima glottidis
What are highlighted arrows
Positions of regions of larynx
Supraglottic compartment is also known as the
Vestibule
(Includes false vocal cords)
What type of epithelium lines the larynx
Pseudostratified ciliated columnar epithelium
True vocal cords are lined with
Stratified squamous
If a patient required incubation, larynx is viewed using
Laryngoscope
Insertion of endotracheal ET tube
Oral cavity, oropharynx, larynx, through vocal cords
Sits in the upper part of the trachea
Small balloon to keep tube in place, ET tube has lumen to allow for mechanical ventilation and oxygenation
What do these pictures show
Vocal cords, abducted in left
Yellow - arytenoid cartilages (moved by intrinsic muscles of larynx and alter size and shape of rima glottidis)
Vocal cords will be abducted before intubation
What is this recess called
valecula
Laryngeal anatomy labels
2 main actions of intrinsic laryngeal muscles
Alter size and shape of laryngeal inlet
Alter tension in and position of true vocal cord
How do intrinsic laryngeal muscles alter size and shape of laryngeal inlet
Muscles within aryepiglottic folds contract
Narrow laryngeal inlet and flatten position of epiglottis
Protecting larynx during swallowing
How do instrinsic laryngeal muscles alter tension in and position of true vocal cords
Muscles within larynx alter position of arytenoid cartilages- vary position of cords
Vocal cords closed together (adducted)
Protecting larynx during swallowing and enables phonation
All intrinsic laryngeal muscles are supplied by the
Recurrent laryngeal of vagus CN X
Right or left
With one exception of the cricothyroid muscle
Vocal cords run from
Arytenoid cartilages to inner surface of thyroid cartilage (level of laryngeal prominence)
Arytenoid cartilages move to alter position of
Vocal cords- narrowing or widening rima glottidis
Majority of muscles that impact vocal cords act to
narrow rima glottidis by adducting vocal cords together
Only one abducts (widens) Posterior cricoarytenoid
What does this show
Arytenoids move relative to one another on cricoid cartilage
Alter position of true vocal cords
And size of aperture (rima glottidis)
Cricothyroid is supplies by the
External laryngeal nerve, branch of the superior laryngeal nerve (branch of CN X)
The internal laryngeal nerve (branch of superior laryngeal nerve) innervates the
Laryngeal mucosa able the vocal cords (supraglottis)
Recurrent laryngeal nerve innervates
The vocal cords and ifnraglottis
Superior and recurrent laryngeal nerves are accompanied by
Arterial branches from the superior and inferior thyroid arteries
Important to avoid vocal cord paralysis in thyroidectomy
Features of supra hyoid muscles
Anterior triangle
4 pairs of muscles all superiorly to hyoid bone (e.g. Digastric)
Features of infra hyoid muscles
Anterior triangle
4 pairs, inferior to hyoid bone (e.g. omohyoid)
Infra hyoid muscles are supplies by
Branches from C1-C3 from cervical plexus
Infrahyoid muscles are also called
Strap muscles
What has to be retracted when thyroid gland surgery happens
Infrahyoid
Suprahyoid muscles purpose
Floor of the mouth
Move and stabilise the hyoid bone and therefore larynx along with infrahyoids
During swallowing, chewing and speaking
Vocal cords when breathing
Abducted (open)
Vocal cords when swallowing
Adducted (closed)
Phonation vocal cords
Adducted
Expired air forced through closely adducted vocal cords
VC vibration creates sound waves
Coughing vocal cord position
Adduct
What determines pitch
tension
High pitched= taut
Low = less taut
Contraction of both cricothyroid muscles = increased tension in vocal cords
Muscle located outside of larynx
Cardinal symptom of laryngeal disease
Hoarseness of voice
Benign causes for a hoarse voice
Infection, inflammation, laryngitis, vocal cord nodules
Concerning pathologies causing hoarseness of voice
Nerve damage, tissue damage
Complete or partial, unilateral or bilateral
Determines effects on phonation and breathing
Features of increasing tension in vocal cords for high pitch
Cricothyroid muscles
Innervated by external branch of superior laryngeal nerve CN X
Closely related to superior thyroid artery
Risk of injury in thyroid surgery- causes hoarseness of voice when attempting higher pitched sounds
Unilateral complete injury (e.g. Division of the nerve) to the recurrent laryngeal nerve causes
Vocal cord on affected side = immobile
Takes up a neutral or paramedical position between abduction and adduction
Opposite cord can compensate a bit
Some hoarseness and weaker cough, passage of air through glottis minimally affected
Presentation if both recurrent laryngeal nerves completely damaged
Both vocal cords assume paramedical position with rima glottidis becoming extremely narrow (not completely closed)
Will impair speaking ability and breathing
Recurrent laryngeal nerves and injury
Long courses in neck, especially left (loops under arch of aorta before ascending back up in groove between oesophagus and trachea)
Susceptible to disease and injury affecting neck and upper chest
Left recurrent laryngeal nerve can be affected by
Aortic arch aneurysms
Right recurrent laryngeal nerve can be affected by
Right apical lung tumours
Features of carcinomas of larynx
Present with voice and/or airway problems
Hoarseness of voice often earliest presenting sign of lesions involving the vocal cords
Prognosis of laryngeal cancer
Small and involves glottis = favourable prognosis as minimal lymphatic drainage
Supra and infra glottis regions drain to neck nodes and paratracheal nodes respectively and have poorer prognosis
Larynx during swallowing
Tongue pushes epiglottis posteriorly and aryepiglottic muscles contract, Narrowing laryngeal inlet , Epiglottis position horizontally
Hyoid bone elevated and move anteriorly by Suprahyoid muscles, Soft pallets raises
Adduction of true vocal cords, closure of rima glottidis
Food/fluid is directed over curved upper surface of epiglottis into
Piriform fossa of laryngopharynx
Can be a site for foreign bodies to get stuck e.g. fish bone
Suprahyoids act to
Elevate and anteriorly displace the larynx
Ensures patency of pharynx so food can be safely directed into it and not larynx
Sensory and motor nerves supplying larynx
External branch of superior laryngeal nerve has a route close to
Superior thyroid artery
Recurrent laryngeal nerves pass anteriorly to
Right subclavian SCA
What happens in a cough
Explosion of compressed air
Inspire and fill lungs with air, vocal cords adduct, expiratory muscles contract, intrathoracic pressure builds, then cords suddenly abducted, explosive outflow of air
What Laryngitis
Inflammation of the larynx, often involving true vocal cords
How do you diagnosis laryngitis
Clinically from history
hoarse/weak voice and sore throat
History of URTI
Typical causes of laryngitis
Infectious (viral typically), and non-infectious aetiology
usually self limiting: fully resolves within 2-3 weeks
Features of laryngeal tonsils
Acute trauma or chronic irritation
Hoarseness of voice more than 3 weeks
requires visualisation of cords +/- biopsy
Conditions affecting the larynx
Laryngitis
Laryngeal nodules
Laryngeal cancer
Laryngeal oedema
Epiglottis
Croup
Causes of laryngeal oedema
Allergic reaction or swallowed foreign body (choking)
certain conditions causing swelling of the larynx can present an immediate threat to the airway
Presentation?
Stridor, raised respiratory rate, distress, hypoxia +/- cyanosis
Decreased conscious levels cause
Decreased tone and suppression of reflexes
Airway at risk
2 forms of airway management
Planned (elective) = surgery
emergency = acute/immediate threat to airway or unconscious patient e.g. cardiac arrest
What is Ludwig’s Angina
Rare infection of tissues of floor of oral cavity
Simple airway manoeuvres
Head tilt chin lift
Types of airway adjuncts
Maintain patent upper airway
Oropharyngeal airway (Guedel), contraindicated if minimal depression of consciousness (illicit gag reflex)
Nasopharyngeal airway
Allowing for spontaneous ventilation offers no
Protection of Lower repository tract (from vomit/secretions)
Supraglottic airway management
iGel
Maintains airway and affords some protection, minimal technical skills requires to insert, often first line in cardiac arrest, not for long-term ventilation e.g. if in ITU
Definitive airway = intubation
Endotracheal tube
Technical skill = requires use of laryngoscope to visualise vocal cords
Secures and protects from secretions/vomit, lower respiratory tract
Patient (if not in cardiac arrest) anaesthetised prior to insertion
What is this
Nasopharyngeal airway adjunct
Maintains patent airway
What is this
Oropharyngeal airway adjunct
What is this
Endotracheal tube
Definitive airway passing through vocal cords
What is this
IGEL
Supraglottic airway device
Sits around laryngeal inlet
What is croup
Common respiratory disease in children
Barking cough, worse with agitations (stridor may occur)
Caused by a virus
Single dose of corticosteroid
What is Epiglottitis
Inflammation secondary to infection causing swelling of epiglottis and Supraglottic tissues
Rare
2-6 year olds
Stridor, drooling, difficulty breathing and swallowing, high fever, sore throat, sitting upright, sniffing position, mouth open
DO NOT EXAMINE THROAT
Intubation or tracheostomy
Caused by haemophliius influenza, needs antibiotics
