Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

610 Small Animal Radiolo g y and Ultrasono graphy
A
B
Fig. 5-3 A, Normal dorsoventral canine skull radiograph. B, Normal dorsoventral feline skull
radiograph.
so that the uppermost mandible is rotated toward the dorsal portion of the skull. This rotation
causes the upside maxillary arcade (maxillary arcade farthest from the film) to be
superimposed on the nasal passages and the downside maxillary arcade (maxillary arcade
nearest to the film) to be free from superimposition. Care should be taken to ensure that
the tongue does not lie over the region of interest. The second variation of the open-mouth
lateral oblique view is obtained by rotating the maxilla in the opposite direction. This is
used to assess the mandible and mandibular dental arcade (Fig. 5-6, C and D). This view
also requires that the mouth be open, the nose slightly elevated so that the mandible is parallel
to the film for its entire length, and the skull rotated along its linear axis so that the
downside mandible is not superimposed by the other mandible or the maxilla. The degree
of rotation varies with individuals and is best determined at the time of positioning. When
making opposite oblique views, the patient should be turned over rather than rotating the
head dorsally for one view and ventrally for the other.
I N T R AO R A L V E N T R O D O R S A L A N D D O R S O V E N T R A L V I E W S
The intraoral ventrodorsal view, used to evaluate the rostral teeth, is obtained by placing
the patient in dorsal recumbency and then inserting either a cardboard or plastic film cassette
or a nonscreen film into the mouth. When possible, the tongue should be positioned
below the x-ray film or cassette. The tube should be angled slightly toward the caudal part
of the animal. The degree of angulation should be estimated for each individual; the goal
is to have the x-ray beam strike the roots of the mandibular incisors at a 90-degree angle.
This view is helpful in evaluating the mandibular symphysis, lower incisors, and mandibular
canine teeth. The intraoral dorsoventral view is obtained in a similar manner, except the