CAR week 7 - nasal cavities, sinuses, larynx etc.

Name 3 functions of the nasal cavity

1. conduction and preparation inspired of air

2. heat exchangers for cooling the brain

3. olfaction

How does the nasal cavity conduct and prepare inspired air

1. moistens it

2. warms it

3. filters particles

   1. traps particles in mucous → swallowe

How is the nasal cavity involved in heat exhcnage for cooling the brain

• airflow cools venous blood

  • subsequent countercurrent flow with arteries cools arterial blood going ot the brain

how is the nasal cavity involved in olfaction

• caudal regions of turbinates are covered by olfactory epithelium

What are the landmarks of the nasal cavity borders?

1. Dorsal: nasal bones

2. ventral: hard palate

3. Lateral: incisive bone and maxilla

4. Rostral: nares (nostrils)

5. caudally: nasopharynx

6. axially: nasal septum

Outline the nostrils:

1. official name

2. what are they surrounded by

3. what are they supported by

1. nares

2. hairless skin - sometimes highly modified depending on species

3. nasal cartilages

Outline cattle nostrils:

1. what are they surrounded by

2. what cells

3. glands?

1. smooth hairless nasolabial plate

2. stratified cornified epithelium

   1. serous glands create moisture - nasolabial glands too

Outline horse nares:

1. nasal cartilage?

2. cartilage ring?

3. other cartilage?

1. no ventral nasal cartilage

2. incomplete - distensible nostrils

3. alar cartilages - plate and horn

outline alar cartilage:

1. shape

   1. which nostril is ‘true’, which is ‘fake’

1. comma shape

2. ventral is true, dorsal is false. 

   1. skin lined diverticulum, within nasoincisive notch

How is the horse able to improve airflow

they have a significant ability to distend nostrils

Name the muscles that control nostril dilation

• levator nasoabialis

• caninus

• transversus nasi

what nerve innervates and what artery supplies the nostril dilators?

• facial nerve

  • facial artery

what divides the nasal plate in dogs and cats?

• philtrum = median groove

what gland secretes near the philtrum in dogs and cats

lateral nasal gland

what is BOAS and what breeds does it affect?

• brachycephalic obstructive airway syndrome

• flat face breeds of cat and dog

what structures are affected by BOAS?

• stenotic nares

• elongated and thickened soft palate

• enlarged tongue

• narrow trachea

how is the quality of life affected with BOAS

• increased breathing and noise

• coughing and shortness of breath

• sleep apnoea

  • exercise intolerance

outline the structure of pig noses:

• nostril size

• sensitivity

  • bones

• small, on a flat mobile snout

• highly sensitive

• rostral bone

Outline the structure of the nostrils in birds

• slit like openings (not in diving birds)

• operculum: overhanging bony flap

what is the nasal vestibule

• the opening of the nasal cavity 

What does the nasal vestibule contain and what does it receive

• opening of nasolacrimal duct - visible on ventral surface of nasal vestibule (especially in horses)

• receives nasal gland secretions in dogs

Outline the nasal osteology:

• dorsal

• lateral

• ventral

• caudal

• axial

• nasal bone 1

• incisive bones and maxilla

• palatine bone

• ethmoidal bone

• nasal septum

what are choanae

paired caudal openings of the nasal cavity

what divides the nasal cavity

• nasal septum

  • further divisions by nasal conchae

what are nasal conchae and what are their role

• scrolls of turbinate bone covered in mucosa

• increase nasal surface area and are highly vascular

what are the 3 conchae found in horses

• dorsal

• middle

  • ventral

what are nasal meati (meatus singular)

• passages of air flow: dorsal, ventral and middle

• simple in horses, more complex in dogs

What 4 meati are there in a horse and where do they lead to

1. dorsal meatus → olfactory mucosa

2. middle meatus → paranasal sinuses

3. common meatus

4. ventral meatus → pharynx

how does cattle middle meatus compare to a horses’

• very small

when placing a nasal tube through which meatus do we want to travel?

• ventral

Label this diagram

1. rostral concha

2. middle concha

3. caudal concha

what cells do we find in the vestibule?

stratified squamous epithelium

How does the function of the epithelium change as we travel through the nasal cavity

Starts as respiratory

Label a-d and state what epithelium we find/function

a = vestibule = transition from integument (skin) to mucous membrane

b = nasal cavity = respiratory epithelium

c = caudodorsal part of ethmoidal conchae: olfactory epithelium

d = vomeronasal organ: olfaction

what makes up respiratory mucosa

• epithelium and lamina propria

Describe the cells found in the respiratory epithelium

Pseudostratified ciliated columnar goblet cells

what are cavernous bodies and where do we find them

• thin walled veins

• in the lamina propria

what are the structures found in the lamina propria

1. capillary net

2. nasal glands

3. venous cavernous bodies

4. artery

5. periosteum

6. vein

5 functions of the respiratory epithelium

1. regulating air flow of erectile tissue

2. cleaning (cilia)

3. humidification (evaporator)

4. protecting reflexes (sneeze reflex)

what are ethmoturbinates, where do we find them and what action do animals perform to bring air into contact with them?

• they extend rostrally from the ethmoid bone - olfaction

• covered with respiratory epithelium

• contain olfactory sensory neurones

• sniffing - alters normal airflow to bring it into contact with them

what do we find in the olfactory region and what CN is involved?

1. olfactory cells

2. non-motile cilia-like structures: olfactory receptors that detect chemicals

3. CNI

Outline the vomeronasal organ:

1. what is its function

2. where is it found

3. what is unique about it

4. what role does it play?

5. what behaviour indicates it’s being used?

1. accessory olfactory sense organ

2. within the hard palate

3. it has unique chemoreceptors distinct from other olfactory organs

4. pheromone detection

5. Flehmen’s response = lip curling

what may unilateral discharge from the nose of a horse indicate?

• sinus related problem

• sinuses drain into nasal cavity but aren’t connected on the L/R side therefore unilateral drainage = sinus problem

How do we get airflow resistance?

• turbinates - but this is necessary for air preparation

• resistance of radius of nasal cavity: ½ radius = 16x more resistance (resistance = length/radius^4)

• nasal cavity, pharynx and larynx cause >60% flow resistance

How do horses help reduce airflow resistance?

• less complex turbinates to reduce resistance

• flow is aided by a straighter head-neck-thorax alignment

What are paranasal sinuses?

• air filled diverticula of the nasal cavity: invaginated skull bones

Outline the structure of the paranasal sinuses:

1. lining

2. innervation

3. species variation

4. separation

1. respiratory epithelium (same as nasal cavity)

2. V1 and V2 branches of CNV

3. a lot but all have frontal and maxillary sinuses

4. R/L side of head

Name 5 functions of the sinuses

1. resonating cavities: voice

2. insulation/cooling (brain)

3. reduces weight of skull

4. increased insertion surfaces

5. space for teeth

What sinuses can we identify here?

green = frontal

all other colours = divisions of the maxillary

what is the frontomaxillary opening?

where the frontal sinus connects to the maxillary sinus

Name the 2 different sinuses

1. frontal

   1. maxillary

Name the 2 frontal sinuses

1. frontal

2. dorsal conchal

Name the 4 maxillary sinuses

1. rostral maxillary

2. caudal maxillary

3. ventral maxillary

4. sphenopalatine

Identify the sinuses

Orange: frontal

Red - caudal maxillary

Bright green = rostral maxillary

Dark green = ventral maxillary

Na

Name the sinuses

Orange = frontal sinus

bright red = caudal maxillary

bright green = rostral maxillary

dark green = ventral conchal

Identify the sinuses

1. orange = frontal

2. dark red = dorsal conchal

3. bright green = rostral maxillary

4. bright red = caudal maxillary

5. dark green = ventral conchal

6. yellow = sphenopalatine

How are the frontal and dorsal conchal sinuses drained?

1. frontal and dorsal conchal sinus

2. frontomaxillary aperture

3. caudal maxillary sinus

4. nasomaxillary opening

5. middle meatus

How is the sphenopalatine sinus drained?

1. sphenopalatine sinus

2. caudal maxillary sinus

3. nasomaxillary opening

4. middle meatus

How are the rostral max sinus and ventro conchal sinus drained?

1. rostral maxillary or ventro conchal (not connected together)

2. drain into nasomaxillary opening

3. middle meatus

What kind of tooth roots do horses have? What is their clinical relevance?

• hypsodontal - long routes, especially in young

• upper rows of teeth:

  • 108/208 and 109/209 in the rostral maxillary sinus

  • 110/210 and 111/211 in caudal maxillary sinus

  • clinical relevance - tooth root infections can cause problems in the sinuses 

Outline the nasolacrimal duct:

1. function

2. what does it start with

3. where does it run

4. what does it continue within

5. where does it exit

1. drainage from medial canthus of eye to nasal cavity and drains excess tears

2. starts at nasal puncta

3. within infra-orbital canal (along the tooth apices)

4. nostril(horse/cattle) or nasal cavity (dogs)

Label 1-8, what imaging technique took this image?

1. rostral maxillary sinus

2. ventral conchal sinus

3. infraorbital canal

4. frontal sinus

5. dorsal conchal sinus

6. dorstal meatus

7. middle meatus

8. ventral meatus

9. computed tomography: CT

How will sinus disease usually present?

• chronic unilateral purulent discharge ± facial swelling

How does primary sinusitis differ from secondary?

Causality:

• primary: bacterial

• secondary: dental/cyst/neoplasia

What does the straight line indicate?

• it’s a fluid line in the frontal and maxillary sinus

• indicates fluid is present = pus or blood

What is wrong with this head CT?

• horse has a tooth infection, maxillary sinusitis and fluid

• soft tissue opacity where there shouldn’t be (in the conchae and sinusees)

what is sinus trephination

• drilling a hole into a sinus for flushing/investigation

what can we do to investigate sinuses?

endoscopy

where is the infraorbital sinus in birds?

• under the skin rostroventral to the eye'

  • triangular cavity

Outline cattle horns:

• what are they made of

• what sinus is present int he horn?

• clinical relevance?

1. keratin

2. frontal sinus

3. opened during dehorning in adults

• animal will ‘breathe’ through, predisposing to sinus infection

What 4 nerves are involved in horn innervation?

1. cornual animals- all animals with horns

2. cornual branch of infratrochlear nerve - 90% animals

3. frontal nerve - 15%

4. branches from C1 and C2 - 5% animals

Where do we find the cornual and cornual branch of infratrochlear nerve?

1. halfway between lateral canthus and horn base - along ridge of frontal bone

2. between medial canthus and medial horn base

when dehorning calves:

• what nerve needs to be blocked

• what technique is used

• cornual nerve block only

• burn off

when dehorning cattle and goats:

• what nerve blocks are needed

• what technique

• what does it open up

• when don’t we do it

1. cornual and cornual branch of infratrochlear nerve blocks, maybe region caudal to horn too

2. wire/saw

3. frontal sinus

4. when flies are abundant

Outline goat kids dehorning:

• what do we need to be careful of

• frontal sinus is very small and XS heat can damage the brain

what is the blood supply to the horn of ruminants? What relevance does this have?

Blood supply:

• maxillary artery

• superficial temporal artery

• cornual artery

Dehorning can produce a lot of bleeding if the fetotomy wire isn’t moves quickly enough

Outline deer antlers:

• how do they grow

• what are they covered in?

• how often do they regrow?

• what are they made of?

1. rapidly, bony horns

2. velvet - active cells

3. every year - the active cells lay down bone

4. bone NOT keratin

Outline rhino horns:

1. what are they made of

2. how are the fibres arranged

3. do they have a bony core?

1. keratin 

2. less densely than true horn

3. no

Outline the pharynx:

1. what is it the common cavity of?

2. what is ventral and what is dorsal

3. 3 parts?

1. food and ingesta

2. oral cavity ventral with oesophagus dorsal and the nasal cavity dorssal with larynx and trachea ventral

3. nasopharynx, oropharynx and laryngopharynx

Outline the nasopharynx:

• ventral margin

• rostral margin

• caudal margin

• lateral and dorsal margin

• what’s it lined with?

1. soft palate (continuous with palatine bone)

2. choanae

3. laryngopharynx

4. pharyngeal wall

5. respiratory epithelium

what is the nasopharyngeal recess?

• caudodorsal extension of nasopharynx

  • found in most ungulates

  • blind ending

Outline the oropharynx:

• dorsal margin

• ventral margin

• rostral margin

• caudal margin

• lining?

1. soft palate

2. tongue

3. oral cavity

4. laryngopharynx

5. stratified squamous epithelium

Outline the laryngopharynx:

• rostral margin

• caudal margin

• lateral and dorsal magin

• lining

1. free tip of soft palate

2. larynx and opening of oesophagus

3. pharyngeal wall

4. stratified squamous epithelium

outline the soft palate:

• what does it divide

• structure

• 3 muscles

• innervation

1. pharynx

2. flexible muscular structure 

3. palatinus, tensor veli palatini and levator veli palatini

4. V3 of CNV

where are they found and what are the effects of these muscles:

1. palatinus

2. tensor veli palatini

3. levator veli palatini

1. within the main body - shortens palate

2. within rostral side wall - causes lateral traction and thus tension

3. within caudal side wall - raises palate during swallowing and mouth breathing

What kind of muscle is found in the pharyngeal wall?

• striated

Outline the muscles of the pharyngeal wall:

• what do they do

• what 3 are there

• where do they insert

• what ware they important for

• what’s one muscle with a different function, what is it

• innervation

1. constrict and shorten

2. rostral (palatopharyngeal), middle (hypopharyngeal) and caudal (thyropharyngeal)

3. roof of pharynx > dorsal and lateral arches

4. passage of food

5. dilation - stylophharyngeus caudalis

6. CNX and CNXII

What is the scientific word for swallowing

• deglutition

Outline the steps of deglutition

1. soft palate elevated to obstruct nasopharynx and open oropharynx

2. palatopharyngeal arch constricts

3. hyoid apparatus pulls larynx forward

4. epiglottis flips back to cover tracheal opening

5. tongue pushes food into oesophagus

Outline the guttural pouch (horse)

• where do the auditory tubes run in all species

• what is the guttural pouch

1. from nasopharynx to middle ear in all species

2. a large diverticulum of auditory tube in horses

What are the margins of the guttural pouch in the horse

• dorsal = base of skull

• ventral = laryngopharynx and oesophagus

• lateral = skin

• medial = septum

How can we access the guttural pouch?

• drains can be entered through slits into the nasopharynx

Outline what we find in the guttural pouch:

1. bone?

2. nerves?

3. blood vessels?

4. muscles?

5. lymph nodes

1. stylohyoid bones: divides into lateral and media compartments (SH)

2. CNIX, X, XII

3. internal carotid artery and external carotid artery

4. longus capitus

5. pharyngeal lymph nodes

Outline guttural pouch diseases:

1. bacterial

2. fungal

1. stangles, strep. equi sbsp equi

2. mycosis: signs depend on location of plaques

• could get episttaxis if over artery/neurological disease if over nerve

How can we access the guttural pouch surgically?

Viborg’s triangle - not done often

How can we describe nasal discharge?

• colour

• consistency

• amount

• bilateral or unilateral

• odour and what type

• is blood present

What do each of these descriptions mean:

1. serous

2. mucoid

3. purulent

4. mucopurulent

5. viscous

6. sanguineous

7. epistaxis

8. fetid

9. unilateral

10. bilateral

1. watery

2. opaque white discharge

3. thick yellowish-green discharge often indicating infection

4. mix of mucoid and purulent discharge

5. sticky

6. blood

7. full on nosebleed

8. bad smelling

9. one side

10. both sides

How can we investigate nasal discharge?

1. endoscope

2. culture

3. whole clinical examination - look at teeth

4. bloods

What may these discharges indicate?

1. watery/white no other signs

2. thick yellow discharge that’s bilateral and less active

3. pneumonia

4. strangles

5. flowing blood nasal discharge

6. unilateral bloody discharge

7. creamlike unilateral discharge

8. foamy bilateral

1. asthma/allergies/reacting to environmental irritants

2. viral or bacterial infection

3. Strep. equi subsp. Zooepidemicus

4. S.equi subsp. Equi

5. unless exercise induced pulmonary haemorrhage (EIPH) - needs a vet, could be fungal or bacterial infection

6. dark rust colour and lots of mucous - not fresh bleeding and could be ethmoid haematoma

7. bacterial infectioni of guttural pouch - guttural pouch empyema

8. oesophageal obstruction = choke

Provide advantages of each of these methods:

1. blood sample

2. nasal swab

3. oral radiograph

4. endoscopy

1. easy to take and can give a lot of information - provide details presence and severity of infection

2. culture to determine the presence of specific bacteria

3. observe teeth and see if signs of root infection that could be causing sinus problems

4. early diagnosis and minimally invasive