Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Five The Skull 609
A
B
Fig. 5-2 A, Normal ventrodorsal canine skull radiograph. B, Normal ventrodorsal feline skull
radiograph.
O P E N -MOUTH L AT E R A L V I E W
The open-mouth lateral view is positioned like the standard lateral view except that the
mouth is restrained in an open position (Fig. 5-4). This view aids in evaluating the rostral
portion of the calvarium, because the coronoid processes of the mandibles move ventrally
and do not superimpose upon the frontal and parietal regions, and the upper and lower
dental arcades are not superimposed.
L AT E R A L O B L I Q U E V I E W
The lateral oblique view is obtained by placing the animal in lateral recumbency without
external support to the body or skull (Fig. 5-5). This obliquity causes the structures closest
to the x-ray tube (farthest from the film) to appear as the more ventral of the pair on the
radiograph. In some breeds in which the head is nearly round (e.g., Boston Bulldogs, Pugs),
it may be necessary to elevate the dorsal part of the skull slightly from the table to create
adequate obliquity. This view is particularly useful for evaluating the temporomandibular
joints and osseous bullae. The degree of rotation needed for the ideal evaluation varies with
the head conformation. 1 It may also be helpful in evaluating lesions of the temporal portion
of the calvarium and horizontal ramus of the mandible.
O P E N -MOUTH L AT E R A L O B L I Q U E V I E W
The open-mouth lateral oblique view has two variations. The first is used to evaluate the
maxilla and maxillary dental arcade (Fig. 5-6, A and B). It is obtained by holding the mouth
open with a mouth gag (speculum), tape, or other device; elevating the nose slightly so the
maxilla is parallel to the film for its entire length; and rotating the skull around its long axis