Skull radiography Flashcards
Different cranium types (3)
Dolichocephalic – sighthounds, collies
Mesaticephalic – german shepherd, setters (cranium length same as nose length)
Brachycephalic – bulldogs, boston terriers, pugs etc.
Describe brachycephalic patient skulls. (10)
Domed, thin calvarium (in some breeds thickened).
Ventrally orientated cribriform plate.
Reduced or absent frontal sinuses.
Shortened nasofacial area with crowded maxillary teeth.
Curved mandibles which are relatively longer than the maxillae, resulting in inferior prognathus (underbite).
Small and thick-walled tympanic bullae.
Increased soft palate and peripharyngeal soft tissue.
Excessive submandibular soft tissue (muscle mass and skin).
Caudally displaced hyoid apparatus.
Fontanelles or cranium suture lines may stay open.
Skull radiographical views. (6)
Lateral
VD (or DV)
Intraoral (VD/DV)
Oblique (temporomandibular joints, bullae)
Rostrocaudal
- Open mouth: can view bullas
- Closed mouth: can capture frontal sinus
Caudodorsal
Describe a good Lateral skull view.
Superimposition of structures on both sides.
- Good land marks: check that mandibles and aural bullas are overlaid.
Use pads/foams to support nose and/or jaws.
NB! If supporting materials not clean – artefacts!
Nose (mid-sagittal plane) parallel to table.
You can do open mouth or closed mouth.
Describe a good Dorsoventral skull view.
DV is more preferred than VD → easier to achieve symmetry.
Hard palate needs to be parallel to table/cassette.
For viewing Midline structures, you need to remove intratracheal tube.
Bilateral symmetry is the goal.
Intraoral – teeth, maxilla/mandibula
Describe a good oblique skull view.
If you want to capture the maxilla, it should be positioned closer to the table (see image). And vice versa for the mandible.
Tilt Degree depends on the area and conformation of patient’s head.
- Usually 20-30 degrees
Brachycephalic – usually bigger degree (30+)
Dolicocephalic – usually smaller degree (10)
Sufficient degree will separate superimposed structures adequately.
Head towards DV
- You can more easily view: Frontal sinus, maxilla, upper teeth arcade.
Head towards VD
- You can more easily view: TMJ, bullas, mandibula, lower teeth arcade
whats this
Oblique mandibular view.
TMJ view is also called:
+ describe it
sagittal oblique
To view the temporomandibular joint.
Patient in lateral recumbency, nose lifted 10-30 degrees. Open mouth or closed mouth.
Rostrocaudal closed mouth for viewing…?
Describe positioning.
the frontal sinus
position such as in picture
Rostrocaudal open mouth for viewing…?
Describe positioning.
Tympanic bullae
30 degree angle between beam and hard palate
Describe the rostrocaudal skull view.
cats, brachycephalic breeds
The atlanto-occipital joint gently flexed so that the mandible is about 10 degrees less than vertical.
Review normal anatomy.
Review normal VD/DV anatomy.
Skull fractures radiographically.
Fracture line must be differentiated from suture line. Fractures are not usually symmetrical.
Image has dark line around midline that is not symmetrical = fracture.
fractured mandibula in oblique views
in the right mandibula view you can barely see the fracture due to superimposition of structures so capture both mandibula on their own image.
identify pathology
Subperiostal haematoma
Egg-shell like new thin bone is new bone formation due to repeated mild-moderate trauma.
5 mo Akita that banged its head on its crate repeatedly.
identify pathology
Hydrocephalus
Note the open fontanelle as well.
7 mo Staffordshire terrier mix
identify pathology
left zygomatic arch neoplasia in left image
asterisk marks soft tissue neoplasia in left side image. note the difference in density of that space.
identify pathology
calvarium neoplasia in left image
mandibular neoplasia in right side image
identify pathology
left image: Fracture of retroauricular processus
right: TMJ dysplasia
identify pathology
TMJ neoplasia
but note that osteomyelitis can look very similar
identify pathology
TMJ subluxation
in the closed mouth image the luxation is difficult to discern but in the open mouth view its obvious
identify pathology
TMJ luxation in a cat
Describe craniomandibular osteopathy.
“CMO”
Is a non-neoplastic proliferative bone disease (the new growth grows outward typically).
Usually 3-8 mo old dogs affected
- Especially West Highland white terrier – autosomal recessive.
- Cairn terrier, Scottish terrier
Marked new bone formation in:
- Mandibulae
- Bullae
- In some cases, also the cranium and frontal bone.
Great variability in presentation – bilateral, unilateral, different areas can be affected
Self-limiting disease! changes may even disappear in time
Describe Secondary hyperparathyroidism.
Nutritional Ca+ deficiency that affects mostly vertebrae, bones in limbs.
Secondary hyperparathyroidism can also be caused by Chronic renal failure and in these cases it tends to affect the skull.
Renal dysplasia (in young animals) can also cause it.
Renal issues cause Hyperphosphatemia, hypocalcemia which in turn will stimulate the secretion of parathyroid hormone.
Too much PTH causes Bone resorption:
“Floating teeth”, “Rubber jaw”
identify pathology
Secondary hyperparathyroidism, bone resorption and “Rubber jaw”.
identify pathology
Middle ear disease - polyp
the bulla should be filled with air so it should be almost black but in this image it is not.
identify pathology
Chronic infection, mass in the right canal.
neoplasia and chronic infection will look similar on xray and often a mass will cause infection anyway so both will be present.
identify pathology
Nasopharyngeal mass in cat visible in open mouth view
Xray views for Nasal chambers and frontal sinuses. (3)
What ailments do you look for in these views? (2+)
Lateral/ DV
Intraoral DV
Rostrocaudal (frontal sinus)
Rhinitis
- Bacterial
- Fungal (aspergillosis)
- Foreign bodies
- Lymphoplastocytic
Neoplasia
Review normal anatomy.
Dotted line – cribriform plate
What do you see?
Nasal chambers
R – rostral part
- Numerous slightly wavy parallel lines.
M – middle part. Rounded, more widely spaced lines.
Cd – caudal part. Linear lines.
identify pathology
signs of inflammation or neoplasia. in this case it was Aspergillosis.
identify pathology
3 neoplasia examples (but inflammation looks very similar)
observe difference in density between sides of jaw. it shouldn’t be too dense nor too dark (lytic changes).
You should be able to see turbinate structures in normal states. But note, that fluid will also obscure structures.
