The Hyoid, Larynx And Swallowing

Question 1

What is the hyoid apparatus? Which bones are they?

Answer 1

5 bones associated with the larynx

Stylohyoid, epihyoid, keratohyoid, thyrohyoid, basihyoid

Question 2

Are the hyoid bones paired or unpaired?

Answer 2

All paired except basihyoid

Question 3

The thyrohyoid is attached to what cartilage?

Answer 3

The thyroid cartilage

Question 4

Which 4 muscles are associated with the hyoid apparatus?

Answer 4

Sternohyoideus
Thyrohyoideus
Mylohyoideus
Geniohyoideus

Question 5

Which nerve innervates the thyrohyoideus and sternohyoideus? What is their function?

Answer 5

Cervical nerve

Draw hyoid causally

Question 6

What is the innervation and action of the mylohyoid?

Answer 6

Trigeminal

Draw hyoid rostrally

Question 7

What is the innervation and action of the geniohyoideus?

Answer 7

Hypoglossal nerve

Draw hyoid rostrally

Question 8

Why is the larynx hard to see on the radiograph of younger animals?

Answer 8

Less calcified

Question 9

What is the primary and secondary function of the larynx?

Answer 9

Protect lower respiratory tract from foreign bodies

Vocalisation

Question 10

What type of tissue makes up the larynx? What does the hyoid apparatus do in terms of the larynx?

Answer 10

Cartilaginous and smooth muscle tube

Suspends larynx from skull

Question 11

What is the vestibule of the larynx? What is its entrance called?

Answer 11

Funnel shaped part,ventral floor is the epiglottis
Lies rostrally
Laryngeal aditus

Question 12

What are the cartilages of the larynx?

Answer 12

Thyroid
Epiglottis
Arytenoid
Cricoid

Question 13

Are the cartilages of the larynx paired or unpaired?

Answer 13

All unpaired except arytenoid

Question 14

What shape is the arytenoid cartilage? What shape is the cricoid cartilage?

Answer 14

2 horned

Ring - thicker at top

Question 15

Does nasal breathing take place above or below the soft palate?

Answer 15

Above

Question 16

What is the vestibular fold?

Answer 16

The mucosal fold at the end of the vestibule

Question 17

What is the vocal fold? What is it’s function?

Answer 17

The vocal chord - vocalisation

Question 18

What is the aryepiglottic fold?

Answer 18

Mucosal fold from arytenoid to epiglottis

Question 19

How many pairs of muscles open the glottis? How many pairs open it?

Answer 19

7 pairs close

1 pair open

Question 20

What is the function of the cricoarytenoideus dorsalis? IMPORTANT

Answer 20

Abducts arytenoid

Opens glottis

Question 21

Which is the only muscle to open the glottis?

Answer 21

Cricoarytenoideus dorsalis

Question 22

Give one example of a muscle which closes the glottis and innervation

Answer 22

Cricoarytenoideus lateralis
Laryngeal nerve (runs up trachea)

Question 23

What is the laryngeal saccule? What is it’s opening called?

Answer 23

Pocket in the larynx

Laryngeal ventricle of larynx

Question 24

Brachycephalic dogs often need ventriculotomy. Why is this?

Answer 24

Laryngeal saccule eversion (closes on itself - struggle to breathe)

Question 25

Which nerves supply the larynx

Answer 25

Vago-accessory complex
Cranial laryngeal nerve (AE, VE, SVE)
Recurrent laryngeal nerve (AE,EE, SVE)

Question 26

Roaring in horses is due to what? How is this caused? What is the solution?

Answer 26

Laryngeal collapse
Paralysis of cricoarytenoideus dorsalis
Surgery - suture arytenoid cartilage open

Question 27

The larynx is very sensitive and reflexes. Why might local anaesthetic be needed when tubing an animal before an operation?

Answer 27

Irritation causes coughing and closure of the glottis

Question 28

When swallowing, what happens?

Answer 28

Tongue squeezes bolus
Glottis closes
Hyoid apparatus swings forward
And reverses

Question 29

The swallowing reflex is innervates by which nerve for afferent and efferent?

Answer 29

Afferent - glossopharyngeal, vagus

Efferent - vago-accessory complex