10.1.4 Larynx During Swallowing

Question 1

What happens to the larynx during swallowing?

Answer 1

Tongue pushes epiglottis posteriorly and aryepiglottic muscles contract
- narrows laryngeal inlet
- epiglottis positioned horizontally

Question 2

What happens to the hyoid during swallowing?

Answer 2

Hyoid bone elevated and moved anteriorly by suprahyoid muscles

Question 3

What happens to the true vocal cords during swallowing?

Answer 3

Adduction of true vocal cords, closure of the rima glottidis

Question 4

What happens to bolus in the mouth as it reaches the epiglottis?

Answer 4

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

Question 5

How is the epiglottis curved?

Answer 5

Epiglottis is curved anteriorly, curved in the exact same way as the tongue

Think of it as a mini tongue?

Question 6

What is the function of the suprahyoid muscles during swallowing?

Answer 6

-Suprahyoids act to elevate and anteriorly displace the larynx

-Ensures patency of pharynx so food/fluid can be directed into oesophagus and not larynx

Question 7

What are all the sensory and motor nerves supplying the larynx dervied from?

Answer 7

Vagus, CNX

Question 8

What are the 3 main branches of the vagus nerve?

Answer 8

Superior laryngeal nerve
- Internal branch
- External Branch

Recurrent laryngeal nerve

Question 9

What is the function of the internal branch of superior laryngeal?

Answer 9

Purely sensory, sensory for supraglottis and glottis

Question 10

What is the function of the external branch of the superior laryngeal?

Answer 10

Purely motor, only supplies the cricothyroid muscle

Route is close to the superior thyroid artery

Question 11

What is the function of the recurrent laryngeal nerve?

Answer 11

Motor and Sensory

Motor to all intrinsic muscles of the larynx except for cricothyroid

Sensory to infraglottis

Question 12

What is the route of the Right recurrent laryngeal nerve?

Answer 12

Loops under the right subclavian

Ascends in tracheo-oseophageal groove, basically behind the oesophagus and trachea

Question 13

What is the route of the Left recurrent laryngeal nerve?

Answer 13

Loops under arch of aorta

Ascends back up in tracheo-oesophageal groove

Question 14

What are the recurrent laryngeal nerves closely related to?

Answer 14

Closely related to thyroid and inferior thyroid arteries

Risk of damage to nerve in thyroid surgery, can lead to paralysis of muscles moving TVC

Question 15

How can the recurrent laryngeal nerve be injured?

Answer 15

• Disease or surgery involving larynx, oesophagus or thyroid
• Aortic arch aneurysm (affects left)
• Cancer involving apex of the lung (affects the right)

Question 16

What does a unilateral RLN lesion lead to?

Answer 16

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

Question 17

What does paramedian position mean?

Answer 17

Between fully abducted and fully adducted

Question 18

What happens to airflow in unilateral RLN injury?

Answer 18

No significant impairement to airflow, as rima glottidis still wide enough to allow airflow

Question 19

What happens in bilateral RLN injury?

Answer 19

Bilateral RLN lesions RARE

Narrow rima glottidis, both VCs are in paramedian position

significant airway obstruction, emergency surgical airway, access below VCs