Upper Resp. Passageways- Paranasal sinuses, Anatomy of Nasopharynx (Equine) Flashcards
what are these structures
what are these structures of the nasal cavity in the equine
what are these structures
what are the palpable landmarks
where do the dorsal and ventral nasal conchae form sinuses
4-5th cheek teeth (also in ruminants)
what are the features of nasal mucosa
very vascular
blood volume alters width the airways
prone to epitaxis
which concha are less developed in equines
olfaction ethmoidal conchae
middle concha
what are the conchae present
ethmoidal = top
what are the structures 1-4
- dorsal
- middle
- ventral
- olfaction ethmoidal conchae
nasal cavity transverse section of horse
what are the 5 pairs of paranasal sinuses
- frontal sinus
- dorsal conchal sinus
- maxillary sinus (rostral and caudal compartments)
- ventral conchal sinus
- sphenopalatinue sinus
why are the paranasal sinuses clincally important in horses
- bacterial infection, nasal tumours
- access to upper cheek teeth
- complex and extensive
what are the paranasal sinuses grouped as because of intercommunication
- ventral conchal/rostral maxillary sinuses
- all others
anatomy of paranasal sinuses
anatomy of paranasal sinuses
where is the location of the frontal sinus
internal and external plates of frontal bone
what is the frontal sinus separated by
left and right sides separated by bony septum
where does the frontal sinus extend to
rostrally from level with TMJ to level of eye orbit
what does the frontal sinus communicate with
rostrally with dorsal conchal sinus via conchofrontal sinus
caudal maxillary sinus via frontomaxillary opening
what separates rostral and caudal maxillary sinuses
bony septum
what does the caudal maxillary sinus communicate with and how
conchofrontal sinus via frontomaxillary opening
what does the sphenopalatine sinus communicate with
caudal maxillary sinus
what does the ventral conchal sinus communicate with
rostral maxillary sinus
what does the rostral maxillary sinus communicate with
nasal cavity via nasomaxillary opening (located in middle meatus)
what are the intercommunication between paranasal sinuses of the horse
what are the cheek teeth that fill the maxillary sinus
3rd and 4th upper cheek teeth - rostral maxillary sinus
5th and 6th upper cheek - caudal maxillary sinus
what are the sinuses
what does the maxillary sinus increase with
age
teeth wear and grow down and rostrally enlarging the maxillary sinus (RMS)
what is trephining
infection alleviated
allows drainage and flushing out
what are the clinical landmarks of paranasal sinuses for surgery
- median cathus of eye
- nasoincisive notch
- facial crest
- infraorbital foramen
what are the clinical landmarks of the maxillary sinus
- rostral: line through infraorbital foramen
- caudal: transverse line through middle of the eye
- dorsal: line from the medial canthus of the eye to infraorbital foramen
- ventral: facial crest and just rostral to its end
what are the clinical landmarks of the frontal sinus
- rostral: transverse line 1/2 way between medial canthus of eye and nasoincisive notch
- caudal: transverse line taken 1/2 way along zygomatic arch
- dorsal: approx. 2cm from the midline
- ventral: dorsal to line from medial canthus of eye to nasoincisive notch
what are the features of the soft palate of the nasopharynx in equine
extremely long
explains why the equine is an obligate nasal breather
what is the palatopharyngeal arch
cadaul edges of soft palate
forms a soft cuff around the aditus (entrance) of the larynx
what is the net effect of the soft palate and the palatopharyngeal arch
laryngeal entrance (aditus) held permanetly up in nasopharynx
where is the epiglottis held
above soft palate
what is the pharyngeal recess and what are the implications
median recess located dorsally of nasopharynx
very deep
implications for passing stomach tube
what are tubal tonsil located
close to opening of auditory tubes
where are the entrance to the auditory tubes
long, slit like located on lateral walls of nasopharynx
supported by flaps of cartilage
lined with resp epithelium
what is occuring here
soft palate displacement
the epiglottis has slipped below soft palate
what are these structures
auditory tube openings
what is the guttural pouches lined with
mucosa lining the auditory tubes expands into diverticulum on each side
how is the guttural pouch divided in
stylohyoid bone into medial and lateral compartment
air filled
resp. epithelium
what is this structure
guttural pouch
what is the clinical relevance of the medial compartment of the guttural pouch
cranial nerves: glossopharyngeal (IX), vagus (X), accessory (XI), hypoglossal (XII)
continuation of sympathetic trunk
internal carotid artery
what is the clinical relevance of the lateral compartment of the guttural pouch
cranial nerve: facial nerve (VII)
external carotid artery
external maxillary vein
what is ventral to each guttural pouch
retropharyngeal lymph nodes
what is this structure
what is the function of the guttural pouch
unknown
influence internal carotid artery blood pressure or cerebral blood cooling mechanism
what is the clinical importance of the guttural pouch
infection common
leads to visible swelling and erosion of mucosa lining of the pouch resulting in epitaxis
what does chronic guttural pouch cause
pressure on cranial nerves (IX, X) –> pharyngeal paralysis and/or laryngeal paralysis
damage to facial nerve (VII) –> rare facial paralysis
hemorrhage from internal carotid artery
abscess in retro-pharyngeal lymph nodes –> strangles
