18 Larynx

Question 1

What are the functions of the larynx?

Answer 1

• Airway protection
• Ventilation
• Cough reflex (bring vocal cords together, increase pressure in thorax
• Phonation (production of sound)

Question 2

What bone is the larynx suspended from? Where does the larynx begin and end?

Answer 2

Suspended from: hyoid bone

Begins: Laryngeal inlet

Ends: lower border of cricoid cartilage

continues as trachea

Question 3

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Answer 3

Question 4

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Answer 4

Question 5

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Answer 5

Question 6

When would a cricothyroidotomy need to be done? How is it done?

Answer 6

Patient cannot be intubated or ventilated (swelling of vocal cords)

Intubation via cricothyroidmembrane

Question 7

The larynx is lined with a mucous membrane that folds to form 3 regions. What are these 3 regions called?

Answer 7

Question 8

The larynx forms part of the respiratory tract which is lined with pseudostratified columnar epithelium with thee exception of the true vocal cords. What epithelia are the true vocal cords lined with?

Answer 8

Stratified squamous

Question 9

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Answer 9

Question 10

What functions (actions) do th intrinsic laryngeal muscles allow for?

Answer 10

Question 11

There is only one muscle that abducts the vocal cords (one of the intrinsic muscles). Name this muscle.

Answer 11

Posterior cricoarytenoid

Question 12

What nerves are the intrinsic laryngeal msucles supplied by?

Answer 12

• All except crycothyroid= recurrent laryngeal nerve of vagus
• cricothyroid= external branch of superior laryngeal nerve

Question 13

How do the vocal cords faciliatate phonation?

Answer 13

Question 14

Answer 14

Question 15

How is the pitch of sound (during phonation) determined? (which muscle, what effect does it have)

Answer 15

Cricothyroid muscle

Contraction- increases tension in vocal cords

High pitched sounds –> vocal cords taut

Low pitched sounds –> vocal cords less taut

Innervated by superior laryngeal nerve (branch of X vagus)

Question 16

What will be the effect of injury to the superior laryngeal nerve (closely related to superior thyroid artery)?

Answer 16

Hoarseness of voice- especially when trying to make high pitched sounds

Question 17

Online the how the vagus innervated the larynx.

Answer 17

Question 18

Useful info about superior laryngeal nerve.

Answer 18

Question 19

Outine the route of the recurrent laryngeal nerve and what it innervates

Answer 19

Innervates:

• Motor- All intrinsic muscles of larynx except cricothyroid
• Sensory - infraglottic region

Question 20

How might a unilateral recurrent laryngeal nerve palsy present?

Answer 20

Hoarseness of voice

Ineffective cough (can’t bring vocal cords to midline)

Question 21

Give some potential causes of injury to the recurrent laryngeal nerve

Answer 21

1. During thyroid surgery- (close relation to inferior thyroid artery)
2. Aortic arch aneurysm (left)
3. Cancer involving apex of lung (right)
4. Disease/surgery involving larynx/oesophagus/thyroid

Question 22

What position do paralysed vocal cords assume?

Answer 22

Paramedian position

Question 23

What might need to be done if a patient has a bilateral recurrent laryngeal nerve palsy?

Answer 23

Emergency crycothyroidotomy

Question 24

Identify some conditions affecting the larynx that cause swelling and can threaten the airway.

Answer 24

Question 25

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Answer 25

Question 26

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Answer 26