10.1.4 Larynx During Swallowing Flashcards
What happens to the larynx during swallowing?
Tongue pushes epiglottis posteriorly and aryepiglottic muscles contract
- narrows laryngeal inlet
- epiglottis positioned horizontally
What happens to the hyoid during swallowing?
Hyoid bone elevated and moved anteriorly by suprahyoid muscles
What happens to the true vocal cords during swallowing?
Adduction of true vocal cords, closure of the rima glottidis
What happens to bolus in the mouth as it reaches the epiglottis?
Directed over curved upper surface of epiglottis into piriform fossae of laryngopharynx
Fish bone can get stuck in the piriform fossae, may need surgery to remove
How is the epiglottis curved?
Epiglottis is curved anteriorly, curved in the exact same way as the tongue
Think of it as a mini tongue?
What is the function of the suprahyoid muscles during swallowing?
-Suprahyoids act to elevate and anteriorly displace the larynx
-Ensures patency of pharynx so food/fluid can be directed into oesophagus and not larynx
What are all the sensory and motor nerves supplying the larynx dervied from?
Vagus, CNX
What are the 3 main branches of the vagus nerve?
Superior laryngeal nerve
- Internal branch
- External Branch
Recurrent laryngeal nerve
What is the function of the internal branch of superior laryngeal?
Purely sensory, sensory for supraglottis and glottis
What is the function of the external branch of the superior laryngeal?
Purely motor, only supplies the cricothyroid muscle
Route is close to the superior thyroid artery
What is the function of the recurrent laryngeal nerve?
Motor and Sensory
Motor to all intrinsic muscles of the larynx except for cricothyroid
Sensory to infraglottis
What is the route of the Right recurrent laryngeal nerve?
Loops under the right subclavian
Ascends in tracheo-oseophageal groove, basically behind the oesophagus and trachea
What is the route of the Left recurrent laryngeal nerve?
Loops under arch of aorta
Ascends back up in tracheo-oesophageal groove
What are the recurrent laryngeal nerves closely related to?
Closely related to thyroid and inferior thyroid arteries
Risk of damage to nerve in thyroid surgery, can lead to paralysis of muscles moving TVC
How can the recurrent laryngeal nerve be injured?
- Disease or surgery involving larynx, oesophagus or thyroid
- Aortic arch aneurysm (affects left)
- Cancer involving apex of the lung (affects the right)
What does a unilateral RLN lesion lead to?
Unilateral true VC palsy, hoarse voice, ineffective cough
Cannot fully adduct the vocal cords, therefore cannot build intra-thoracic pressure, therefore, ineffectual, breathy cough
VC stuck in paramedian position
What does paramedian position mean?
Between fully abducted and fully adducted
What happens to airflow in unilateral RLN injury?
No significant impairement to airflow, as rima glottidis still wide enough to allow airflow
What happens in bilateral RLN injury?
Bilateral RLN lesions RARE
Narrow rima glottidis, both VCs are in paramedian position
significant airway obstruction, emergency surgical airway, access below VCs
