H&N 11: The Larynx Flashcards
What are the functions of the larynx?
Involved in phonation, ventilation, cough reflex, protection of the lower respiratory tract, swallowing
Which ligament attaches the epiglottis to the thyroid cartilage posteriorly?
The thyroepiglottic ligament
How does the epiglottis move during swallowing?
Epiglottis is pulled down towards arytenoid cartilages to close off the larynx and prevent aspiration.
Food bolus is directed lateral to the epiglottis into the piriform fossa.
Where do the superior horn and inferior horn of the thyroid cartilage articulate to?
Superior horn articulates to hyoid bone
Inferior horn articulates to cricoid cartilage
What shape is the cricoid cartilage?
Signet ring shaped (narrow anteriorly and broad posteriorly)
At what spinal level is the inferior border of the larynx?
C6
What do the vocal cords attach to?
Attach to the inner surface of the thyroid cartilage anteriorly (fixed point), and arytenoids posteriorly (movable)
What muscles move the vocal cords?
The intrinsic laryngeal muscles (ABduct and ADduct)
What attaches to the arytenoids?
The vocal cords and internal laryngeal muscles
Which membranes are involved in the attachment of the thyroid cartilage superiorly and inferiorly?
Thyroid cartilage is attached to hyoid bone superiorly by thyrohyoid membrane
And attached to cricoid cartilage inferiorly by the cricothyroid membrane
What membrane is pierced in a cricothyrotomy?
The cricothyroid membrane
Emergency procedure so the patient can breathe if there is an obstruction at/ above the larynx and intubation is unsuccessful
What are the true and false vocal cords?
Vocal folds = true vocal cords
Vestibular folds = false vocal cords
How are the vocal cords positioned in respiration, phonation and during swallowing?
Respiration: ABducted
Phonation: partially ABducted
Swallowing: ADDucted
What is the innervation of the intrinsic muscles of the larynx?
All innervated with the inferior laryngeal nerve (branch of recurrent laryngeal nerve) EXCEPT cricothyroid
(Posterior cricothyroid is the only muscle to ABduct, all the the rest ADduct)
Where is the supraglottis?
From the inferior surface of the epiglottis to the false vocal cords
Where is the glottis?
The vocal cords and 1cm between them
Actual opening between the vocal cords is the rima glottidis
Where is the subglottis?
From the lower border of the glottis to the inferior border of the cricoid cartilage
What does the superior laryngeal nerve innervate?
Internal branch: sensory to the supraglottis
External branch: motor to the cricothyroid
What does the recurrent laryngeal nerve innervate?
Sensory to the subglottis
Motor to all of the intrinsic muscles of the larynx except the cricothyroid
What could cause a recurrent laryngeal nerve palsy?
Apical lung cancer Aortic aneurysm Laryngeal cancer Thyroid disease Cervical lymphadenopathy Diabetes During thyroid surgery
How would a unilateral recurrent laryngeal nerve palsy present differently to a bilateral palsy?
Unilateral = hoarseness of voice Bilateral = no phonation and breathing impaired
What are some symptoms of laryngeal cancer?
Hoarseness of voice Foreign body sensation in throat Dysphagia Odynophagia Coughing Weight loss Otalgia (referred pain from vagus)
What increases the risk of laryngeal cancer?
Smoking and alcohol
Is laryngeal cancer more common in men or women?
5 x more common in men