Larynx (neuroanatomy 3.5)

Question 1

Describe the vocal folds (or cords) within the larynx

Answer 1

• Vocal folds
• Just above we have vestibule
• Beneath this infraglottic space
• Glottis

Question 2

Describe the laryngeal opening

Answer 2

• Laryngeal opening using an endoscopic view
• Back of tongue and then epiglottis
• Vestibule
• Tracheal rings, vocal folds and vestibular folds
• Structure of vocal cords with endoscopic camera

Question 3

What are the muscles of the larynx?

Answer 3

1. Arytenoid muscle
2. Posterior crico-arytenoid muscle
3. Lateral crico-arytenoid muscle
4. Cricothyroid muscle

Question 4

What is the arytenoid muscle?

Answer 4

most important in terms of movement

Question 5

What is the posterior crico-arytenoid muscle?

Answer 5

Posterior crico-arytenoid muscle from the cricoid cartilage to the arytenoid cartilage - contraction of posterior cricoaryenoid will open up or about to the vocal folds

Question 6

What is the lateral crico-arytenoid muscle?

Answer 6

Lateral cricoarytenoid muscles - from cricoid cartilage to arytenoid and contraction of this muscle will close or aduct the vocal field

Question 7

What is the cricothyoid muscle?

Answer 7

contraction of this will tense the vocal folds and will change the pitch of noise produced by air flow between them

Question 8

What are the protective mechanism of the airway?

Answer 8

• Swallowing reflex where larynx is raised
• Epiglottis retroflex is over the opening of the away and stops food going into airway
• Gag reflex
• stops you swallowing something you don’t want to
• By touching the pharynx at the back of the tongue, the glossopharyngeal nerve (CN9) is underlying that reflex

Question 9

What are two protective mechanisms invoking expulsion of air at some speed?

Answer 9

Sneezing: expel air through the nose and try to clear obstructions or irritations of the nose Coughing: have reflex action to try and get food away from airway and out through hr mouth right now

Question 10

What is the innervation of the larynx like?

Answer 10

• Via branches of the vagus nerve
• Thyroid cartilage, cricoid cartilage
• Trachea going into upper airway

Question 11

What are the two branches of the vagus nerve?

Answer 11

1. Superior laryngeal nerve: two branches itself: internal laryngeal nerve and external laryngeal nerve
2. Reccurent laryngeal nerve: passes down into thorax then comes back up to larynx

Question 12

What happens if there is a lesion in the vagus nerve before any of the branches arise?

Answer 12

Complete paralysis of the larynx

Question 13

What happens if there is a lesion where the internal branch is affected?

Answer 13

Lesion causes a loss of sensation above the vocal cords

Question 14

What happens if there is a lesion where the external branch of the superior branch is affected?

Answer 14

If external branch of superior branch: lesions causes paralysis of crciothyroid muscle, just one of the muscles involved in laryngeal action

Question 15

What happens if there is a lesion that affects the recurrent laryngeal nerve?

Answer 15

paralysis of nearly all muscle of larynx except cricothyroids in there and also a loss of sensation below the vocal cords

Question 16

Where is the thyroid gland?

Answer 16

• Below thyroid cartilage, wrapped around top of trachea is thyroid gland
• Two losses and the isthmus of thyroid sitting here
• Separation between thyroid gland and cartilage
• In thyroid surgery parts of innovation of larynx at risk
• The recurrent laryngeal nerve runs very close to the thyroid. So when surgery’s being carried out on the thyroid, they have to be very careful not to damage the recurrent laryngeal, and paralyze the larynx.

Question 17

What are some veins?

Answer 17

• See superficial veins of neck and most prominent is the external jugular view on either side lying on surface of sternocleidomastoid
• Other veins: Facial vien: drinaing from face down in the internal jugular vine (slightly obscured in diagram) Subclavian vien

Question 18

Where does the opthalamic vein drain?

Answer 18

• Ophthalmic vein drains back into cavernous incus
• Provide a potential route of infection back into cavity also infection round the orbit is potential infection risk into cranial cavity

Question 19

Where does the pterygoid plexus drain?

Answer 19

Pterygoid plexus of deep veins draining ultimately into the internal jugular vein

Question 20

What are two routes for putting in a line to be able to monitor central venous pressure?

Answer 20

• Internal jugular vein
• Subclavian vein

Question 21

What is the most common route for putting in a line to be able to monitor central venous pressure?

Answer 21

• Most common site form introduction of central line is internal jugular vein (then the probe into superior vena cava)
• Alternative is via subclavian vein (don’t want to hit subclavian artery)

Question 22

How do you check lymph nodes?

Answer 22

-Palpate sub-mental and submandibular generally approaching from behind using your hand you can feel these lymph nodes particularly if they are enlarged

Question 23

Describes the lymphatics

Answer 23

• Closely associated with vasculature and views are lymphatics
• See deep cervical lymph nodes tracking down next tot the internal jugular vein just here
• Lymph nodes drawing from buccal cavity in this case from the dentition and here from the chin back towards the deep cervical nodes here and
• Submental under chin and submandibular nodes draining down