Equine Skull

sihirlifil's version from 2017-12-05 21:23

Part 1

Question Answer
Equine skull consists ofMaxilla; nose, paranasal sinus
Mandible; TMJ
Teeth: cheek teeth & incisors
Guttural pouch
Pharynx & larynx
Which projections are done?L/R lateral
Intraoral DV (maxillary incisors)
Intraoral VD (Mandibular incisors)
Lateral oblique: maxilla, mandible & their respective tooth roots
Oblique open-mouth: crowns (occlusal surfaces)
Lateral projection of the guttural pouch
Lateral projection of the larynx/pharynx
Special projections for the TMJ
Lateral projection: center where?Halfway between orbit & rostral opening of infraorbital canal (middle of cheek teeth)
(can palpate facial crest)
DV projection: cassette? beam?Cassette: ventral to mandible
Beam: centered midline at rostral margin of facial crest
DV projection: green arrow? red star?
Arrows: Maxillary sinus
Stars: Rostral margin of facial crest
Bony nasal septum projected between mandibular rami
Which oblique views are taken for the maxillary cheek teeth/roots?Latero 30* dorsal-lateroventral oblique
Which oblique views are taken for the mandibular cheek teeth/roots?Latero 35-45* ventral-laterodorsal oblique
Which view is this?
Latero 30* dorsal-lateroventral oblique (maxillary)
Which view is this?
Latero 35-45* ventral-laterodorsal oblique (mandibular)
The oblique projection for the mandibular cheek teeth is between 35-45*, as opposed to maxillary 30*, because?Mandible is narrower
Where is the cassette placed for the oblique lateral projections of cheek teeth/roots?On side of interest (sharpest image, less penumbra)
What can be seen with the open mouth Latero 10* dorsal-lateroventral oblique and Latero 15* ventral-laterodorsal oblique views? Good for which conditions?Erupted crowns of cheek teeth (Occlusal surfaces)
Useful to dx diastema (abnormal gap between individual teeth), coronal fractures, abnormalities of wear
Which view is this?
Open mouth oblique for crowns of cheek teeth (10*-15*)
What are intraoral projections good for assessing?Fractures
Abnormal number, shape, eruption of teeth
Periodontal pathology, fractures, hypercementosis, EOTRH, caries
Which view is this? pathology?
DV intraoral for MAXILLARY incisors & canines
Which view is this? pathology?
VD intraoral for MANDIBULAR incisors & canines
Which view? problem with this view? star = ?
Lateral view
Mandibular rami, orbits, & dental arcades are superimposed
* = frontal sinus
Which view? why bother with it?
Mandibular rami, orbits, & dental arcades are separated (eliminates superimposition problem)
Projections for guttural pouch & pharynx/larynx: center where?
Which view? * = ? @ = ?
Projections for gutteral pouch (*) and pharynx/larynx (@)
Radiologic signs of skull fractureAbnormal deviation, discontinuity, opacity, & contour of skull bones
Subq gas accumulation
Fluid lines in sinus (hemorrhage)
Fractured nasal bone & maxilla (lateral projection)
Modality? problem?
CT, transverse bone window
Fractures of frontal bone, orbit, & maxilla
Arrow = fluid level in frontal sinus (likely hge)
Preferred modality for skull fractures?CT allows for better assessment of extent & severity of fractures & the structures involved
Sinusitis =Inflammation of the paranasal sinus
Paranasal sinus =Frontal (conchofrontal)
Conchal (dorsal & ventral)
Types of sinusitisPrimary
Secondary: associated with dental disease (tooth root abscess, dental fracture); trauma; sinus cysts
Radiographic signs of sinusitisIncreased ST opacity of sinus/individual compartments: thickened sinus mucosa
Fluid lines, sometimes mineralized concrements
Thickening of the bones forming the sinus (chronic)
Problem? arrows?
Maxillary sinusitis (Lat, L & R oblique)
Arrows: FLUID LINES in rostral maxillary sinus (horizontal soft tissue-gas interface)
(Fluid lines in which sinuses?
Conchofrontal & maxillary
Sinusitis (DV)
Increased ST opacity of L maxillary sinus
Sinusitis (CT transverse & dorsal)
Horse lying on its back, horizontal air-fluid interface
Sinusitis (Scintigraphy: bone scan Technetium 99m MDP IV)
Increased uptake of R maxillary sinus area
Good for when radiographs inconclusive, need to identify which tooth (do CT first)
Sinus cyst =Cyst formation originating from sinus mucosa
Radiographic features of sinus cystIncreased ST opacity associated with paranasal sinus
May have rounded contours, thin mineralized wall
+/- Deformity of skull/enlargement of sinus or nasal chamber involved
Sinus cysts can be found where?Paranasal sinus
Nasal cavities
Nasal conchae
Associated with fluid accumulation in the affected sinus (may not be visible if surrounded by fluid)
Additional problem that cysts can cause?(Partial) obstruction of airway may occur with large cysts
Sinus cyst
Fluid opacity with fluid level & round bony structure (arrows) in location of L maxillary sinus
Sinus cyst
What’s wrong with this horse? (CT transverse ST window)
It’s a bovine silly!
Sinus cyst
Round ST attenuating mass, faint bony contour (mineralized wall of cyst, deformed intranasal bony structures)
Mass effect to opposite side, extending into palatine sinus. No airflow through cavity (occluded)
Ethmoid hematoma
* = soft tissue mass extending from Ethmoid region rostrally (superimposed with orbits/ethmoid turbinates/sinus)
Ethmoid hematoma
Ethmoid hematoma: best way to visualize?Origin, size, & extent of lesion best seen in CT (endoscopy, biopsy --> CT)
Best seen on Lateral radiograph (can see on DV)
What’s the difference between these 2 horses?
Top: Juvenile. 3 deciduous PM, molars haven’t developed yet
Bottom: Old (6 teeth with short roots
What’s going on with this 1-yr-old horse’s R maxillary teeth?
Can see 3 deciduous teeth (caps): 506, 507, 508
Dental buds of permanent 106, 107, 108 apparent
109 erupted
110, 111 developing but not yet erupted
How are teeth numbered in the Triadan system?1, 2, 3, 4 = permanent
5, 6, 7, 8 = deciduous teeth
#01-#11 refers to location in rostrocaudal direction
Eruption cysts & caps: signalment? CS?3-4 year old horses, self-limiting over 1-2 years
Bony swellings along ventral mandible, where mandibular cheek teeth are. Associated with root formation of permanent mandibular premolars
Eruption cysts: become a problem when?If impacted (tooth eruption hampered by other teeth or caps)
Eruption cysts: radiographic signsWide radiolucent periapical space
Thin sclerotic rim
Fine detail of roots of erupting teeth
Bony swelling of mandible
Eruption cyst