Pharynx & Guttural Pouch

Question 1

Describe how the nasopharynx, oropharynx, laryngopharynx and larynx are all connected

Answer 1

Pharynx connects nasal cavity and mouth to the larynx and oesophagus respectively. Its role is to direct food, water & air down the either the trachea or oesophagus

The soft palate dived the rostral portion of the pharynx into the oropharynx and nasopharynx (common caudal portion is laryngopharyngeal)

Larynx connects laryngopharynx with the trachea & contains vocal cords. The epiglottis closes the opening of the larynx during swallowing

Question 2

Outline the structure of the nasopharynx and the structures which in borders

Answer 2

Dorsal to the soft palate
Soft tissue is continuous with palatine bone

Extends from the choanae to the intrapharyngeal opening
Choanae
Opening of nasal cavity into nasopharynx

Lined with respiratory epithelium

Borders
Base of skull
Soft palate
Cranial cervical vertebrae

Question 3

What is the nasopharyngeal recess

Answer 3

Caudodorsal extension of the pharynx
Found in most ungulates

Blind ending

Question 4

What is the pharyngeal diverticulum

Answer 4

Blind ending pouch dorsal to opening of oesophagus

Question 5

Outline the structure of the oropharynx and the structures which in borders

Answer 5

Ventral to soft palate

Extends from the oral cavity (last molar) to the epiglottis
	Involuntary, innervated by IX not V

Lined with stratified squamous epithelium

Borders
	Tongue
	Palate
	Palatoglossal arches

Question 6

Outline the structure of the laryngopharynx

Answer 6

From intrapharyngeal opening to opening of oesophagus and larynx

Contains the epiglottis of the larynx
Details in next lecture

Intrapharyngeal opening:
	Formed from free edge of soft palate and palatopharyngeal arches

Common pharynx
	Between soft palate and epiglottis - feature of man
	Common to both nose and mouth

Question 7

Describe the structure of the soft palate

Answer 7

Divides the pharynx
Covered by respiratory and stratified squamous epithelium

Palatinus muscle 
           Shortens the palate

Question 8

Describe the function of the soft palate

Answer 8

Controlled by two muscles
From muscular process of the temporal bone

	Tensor veli palatini
		Causes lateral traction and thus tension
		Innervated by the mandibular branch of the trigeminal nerve

	Levator veli palatine
		Raises the soft palate
		Swallowing AND mouth breathing

Question 9

Outline the changes in the pharynx during inhalation and swallowing

Answer 9

Swallowing (deglutition)
Soft palate elevated

Palatopharyngeal arch constricts

Hypoid apparatus	
	Pulls larynx forward
	Epiglottis pulled back - protecting larynx

Question 10

Describe the muscles involved in inhalation and swallowing

Answer 10

Pharyngeal Wall

Striated muscles
Constriction and shortening
Rostral (Palatopharyngeal)
Middle (Hypopharyngeal)
Caudal (Thyropharyngeal)

	All insert onto the roof of the pharynx > dorsal and lateral arches

	Important for passage of food

Dilation
	Single muscle :  Stylopharyngeus caudalis

Question 11

Outline the innervation of the muscles used during inhalation and swallowing

Answer 11

Vagus nerve and hypoglossal nerve

If affected it can lead to food aspirations, inability to swallow properly

Question 12

Describe the structure and function of the guttural pouch in horses

Answer 12

Pharyngeal opening of the auditory tube (arrow)

Connecting tunnel between nasopharynx and middle ear

Space between base of skull, atlas, pharynx and oesophagus, located behind ethmoturbinates behind the eye and under the brain

Divided into 2 cavities by the Stylohyoid bone

Function:
Cooling of blood?

Question 13

Which key structures run through the guttural pouch?

Answer 13

-Cranial nerves IX, X, XI

-Internal carotid artery

-Cranial nerve VII

-Internal maxillary artery

-Pharyngeal lymph nodes

Question 14

Describe the relevance of structures passing through and over the guttural pouch

Answer 14

All of the nerves that affect laryngeal and tongue function run through guttural pouch

Fungal infections can erode these structures

Question 15

List the two methods of accessing the guttural pouch

Answer 15

Endoscopy of Guttural Pouch Aerocystoscopy

Viborg’s Triangle

1. Caudal border of mandible

2. Tendon of sternocephalicus

3. Linguofacial vein

Question 16

Describe the clinical relevance of the guttural pouch

Answer 16

Fungal disease
Vascular and neurological complication

Bacterial disease
S equi var equi

Entry into the pouch maybe required
-Viborgs triangle only useful if distended
-Can be achieved with an endoscope or without

Question 17

Describe how you would perform endoscopy of the guttural pouch

Answer 17

To use either:
Chambers Mare Catheter
Kruuse

Nielson Mare Catheter
	Arnolds

     Plastic AI catheter

1. Premeasure catheter to pharynx
2. Insert with tip pointing ventrally and pass through ventral meatus
   3 Having advanced the catheter insert it into the guttural pouch
3. Turn the catheter lateraly

The guttural pouch extends further than the pharynx so if you are in the incorrect postion you should feel the caudal wall of the pharynx