16) The Larynx Flashcards
What are the functions of the larynx? (4)
Ventilation
Airway protection
Cough
Phonation
Describe the location of the larynx:
Between hyoid bone and trachea (C4-C6)
What are the main cartilages making up the larynx?
Epiglottis, thyroid, cricoid and arytenoid
Where does the epiglottis attach?
Anteriorly to hyoid and inferiorly to thyroid cartilage (thryoepiglottic ligament)
What is the function of the epiglottis?
Cover laryngeal inlet to prevent fluids or food entering resp. tract
What is the vallecula and its significance?
Depression between tongue base and epiglottis
Important for intubation of trachea
Describe the movements during swallowing to prevent food entering the respiratory tract:
Epiglottis pulled down and larynx pulled up and forward
How does epiglottitis present?
Sore throat, fever, drooling, sounds on breathing
What is the likely causative organism of epiglottitis?
H. influenzae
Describe the structure of the thyroid cartilage:
Two laminae meeting in midline to create the laryngeal prominence
How is the thyroid cartilage joined to the other cartilages of the larynx and nearby bone?
Joined to hyoid by thyrohyoid membrane
Joined to cricoid by cricothyroid ligament (membrane)
Describe the cricoid cartilage:
Complete ring of cartilage, connected to trachea by cricotracheal membrane
Describe the arytenoid cartilages and what attaches to them:
Sit on top of cricoid posteriorly and are points of attachment for vocal and vestibular ligaments
What is cricoid pressure?
Pressing on cricoid cartilage from front to compress oesophagus and stop regurgitation
What is a cricothryoidotomy?
Making an emergency airway through cricothyroid membrane
What forms the false vocal cords?
Vestibular fold (ligament)
Describe the true vocal cords:
Vocal fold with vocal ligament and vocalis muscles forms true vocal cord. Stratified squamous epithelium
Where do the vocal cords attach?
Anteriorly - thyroid cartilage (fixed)
Posteriorly - arytenoid (mobile)
How are the vocal cords moved?
Intrinsic muscles of larynx pull arytenoids causing them to pivot on cricoid cartilage and move the cords
How would the vocal cords appear during ventilation?
Abducted
How would the vocal cords appear during phonation?
Partially abducted
How would the vocal cords appear during swallowing?
Adducted
What is the only intrinsic muscle of the larynx to be located external to the larynx?
Cricothyroid
What is the function of cricothyroid?
Tense the vocal cords causing higher pitch sounds
What is the innervation to cricothyroid?
External branch of superior laryngeal nerve (CN X)
What muscle causes abduction of the vocal cords?
Posterior cricoarytenoid
What are some functions of the intrinsic muscles of the larynx?
Adduction and abduction
Relaxation and tension of vocal cords
Pulls epiglottis over laryngeal inlet
What are the 3 regions of the larynx?
Supraglottis - epiglottis to vestibular folds
Glottis - cords plus 1 cm
Subglottis - to lower border of cricoid
What does the recurrent laryngeal nerve innervate?
Sensory to subglottis and motor to intrinsic muscles of larynx
What does the internal branch of the superior laryngeal nerve innervate?
Sensory to supraglottis
Following thyroid surgery, a woman presents with a deep, hoarse voice. What has occurred?
Damage to recurrent laryngeal nerve as inferior thyroid artery runs near nerve
What are some causes of recurrent laryngeal nerve palsy?
Thyroid disease Laryngeal cancer Thyroidectomy Apical lung tumour Aortic aneurysm
How does unilateral complete injury of recurrent laryngeal nerve present?
Vocal cords in neutral position
Hoarseness and weaker cough
How does bilateral injury of recurrent laryngeal nerve present?
Difficulty breathing
Stridor
Can’t speak properly
What type are the majority of laryngeal cancers?
Squamous cell carcinoma
What are some risk factors for laryngeal cancer?
Smoking and alcohol
Male
Why is the prognosis of cancer favourable if only the glottis is affected?
Minimal lymphatic drainage for glottis so less likely to spread
What are some symptoms of laryngeal cancer?
Hoarseness Foreign body sensation in throat Dysphagia and odynophagia Otalgia (referred) Cough Weight loss
