5a. Nasal Cavity and Paranasal Sinuses Flashcards
Nose in broad sense comprises:
-external nose
-paired nasal cavities
-paranasal sinuses
External nose in domestic animals
-hardly recognizable
>merges with the muzzle
Nose involved in:
-olfaction
-warming
-humidifying
-cleaning of breathing air
Nostrils:
-many cartilages support their shape
-usually within specialized skin
Horse nostrils:
-within non-modified skin
*can open wide as they are obligate nose-breathers
Nasal plate in dog, sheep/goat:
-modified naked skin with a philtrum
-dogs: moist (no underlying glands
-sheep/goat: usually dry
Moist nasal plate in dog due to:
-overflow of nasal mucous glands
-lateral nasal gland
-licking
Nasolabial plate in ox:
-extensive modified naked skin
-no philtrum
-continues with dorsal lip
-usually moist due to underlying sweat glands
-pattern of grooves unique to each individual
Rostral plate in pig:
-modified naked skin has underlying sweat glands
-round nostril within a moveable strong plate
-supported by rostral bones
Pigs use rostral plate for:
-digging in ground
>able to find certain mushrooms
Nasal cartilages:
-nasal septum
-ventrolateral
-dorsolateral
-lateral accessory
Nasal septum:
-separates left and right nasal cavity/vestibules
Free edge of nasal septum:
-attached to cartilages that support margins of nostrils
Shape of cartilages determines:
-shape of nostril and its opening in different species/individuals
Ala:
-wing
Horse nasal cartilages:
-alar cartilage: common shaped
-when raised, nostrils open up
Nostril in horse divided into:
-true nostril
-false nostril
True nostril: horse
-ventral part
-leading to nasal cavity
False nostril: horse
-dorsal part
-leading to nasal diverticulum
-occupying the nasoincisive notch
Nasal diverticulum:
-skin-lined, blind-ended sac
Horse exercising:
-nostrils are fully open
*nasal diverticulum is minimal or gone
Paired nasal cavities/vestibules size:
-less roomy inside than it appears from outside
-partly filled with conchae
Conchae of nasal cavities:
-delicate, mucosa-covered, fragile laminate-turbinate bones
-project into nasal cavity from dorsal, lateral and caudal walls
Concha(e) names:
-dorsal concha
-ventral concha
-ethmoidal conchae
Dorsal concha:
-attached to nasal bone
Ventral concha:
-attached to maxillary bone
Ethmoidal conchae:
*ethmotubinates
-attached to ethmoid bone
-middle concha
Middle concha:
-not a different concha
-enlarged part of ethmoturbinates in large animals
Conchae in carnivores
-more extensive and branched
Olfactory mucosa in dogs:
-covers an area of ~150cm^2
-more chance to detect prey
*especially prevalent over ethmoturbinates
Ethmoturbinates in dogs:
-ectoturbinates
-endoturbinates
Ectoturbinates:
-ethmotrubinates that grow into sinuses
Endoturbinates:
-ethmoturbinates that remain in nasal cavity
Meatus:
-cleft
Nasal meatus:
-small potential spaces between conchae and surrounding structures
>dorsal
>ventral
>middle
>common
Dorsal meatus:
-between dorsal concha and ceiling
-leads to fundus of nasal cavity
-brings air in contact with olfactory mucosa
Ventral meatus:
-between ventral concha and floor of nasal cavity
Middle meatus:
-between dorsal and ventral conchae
>usually gives access to sinuses
Common meatus:
-between nasal septum and other conchae
What meatuses provide the main airway for breathing air?
-ventral
-common
Nasal mucous membrane:
-thickened by vascular plexuses forming cavernous tissue
-extended by folds of conchae
Nasal mucosa essential for:
-effective olfaction
-warming
-humidifying
-cleaning air
Nasal mucosa epithelium:
-cilia that move the mucus toward pharynx to be swallowed
Intubating:
-need to be careful not to damage the mucosa
-guide instruments (ex. nasal tubes) down the junction of ventral and common meatuses
>guide ventrally and medially
Vomeronasal organ:
-present in all domestic animals
-arises from incisive duct and runs caudally
-involved in detection of pheromones
>results in flehmen reaction
Horse vomeronasal organ:
-incisive ducts do NOT enter mouth
*only communicates with nasal cavity
Paranasal sinuses:
-diverticula of nasal cavity
-excavate skull bones, largely after birth
-narrow (direct or indirect) connection with nasal cavity
*do not communicate with contralateral counterpart
Paranasal sinuses named from:
-the bones they invaded
>especially those invaded first
Paranasal sinuses function:
-not clear, may help in
>thermal and mechanical protection of skull
>increase skull size for muscular attachment without increasing its weight
>resonance of voice
>other functions
Sinuses in dog:
-limited
-frontal sinus can have 3 parts
-maxillary recess
Maxillary recess:
-no true maxillary sinus
-ill-defined recess in maxilla
-freely communicates with nasal cavity
Lateral nasal gland in dog:
-large gland
-lies in lateral nasal wall, close to entrance of maxillary recess
-has serous secretion
Serous secretion of lateral nasal gland of dog:
-drained at rostral end of dorsal concha
-may have social significance in nose-to-nose sniffing when dogs meet
Lateral nasal gland in cats:
-not visible macroscopically
-secretion is mucous instead of serous
Sinuses in ox:
-frontal
-maxillary
-sphenoid
Frontal sinuses in mature ox:
-extend caudally as far as occipital, temporal and more
-dorsal conchal sinus
Dorsal conchal sinus in ox:
-extension of frontal sinuses that extend into cornual process and caudal part of dorsal concha
Maxillary sinuses in ox:
-involves maxilla first then may extended into palatine, lacrimal and sphenoids, ventral concha
Sphenoid sinuses in ox:
-often well developed
-may be extensions of maxillary sinus or arise independently
Sinuses in pig:
-extensive, especially in mature boars
>hard to euthanize them
-frontal sinuses into dorsal conchal sinus
-maxillary sinuses
-sphenopalatine sinuses
Sinuses in horse:
-frontal sinus
-maxillary sinuses
-sphenopalatine sinuses
Frontal sinus in horse:
*conchofrontal sinus
-no direct opening to nasal cavity
-communicates via maxillary sinus
Conchofrontal sinus in horse:
-wide extension to dorsal conchal
Maxillary sinuses in horse:
-rostral and caudal maxillary
-extends to caudal part of ventral conchal sinus
-nasomaxillary aperture communicates with nasal cavity
*trephination
Safe trephination: maxillary sinuses in horse
-drilling into bone
-can give access to sinuses and tooth roots
Developmental differences in sinuses:
-get larger as the animal gets older
>’move forward’
Breed differences in sinuses:
-differences depending on skull structure
Anatomical landmarks for livestock euthanasia:
-not between the eyes always!
-just above the eyes
-go from top for sheep, goat, and alpaca
