Figure 226 Line drawing of photograph representing radiographic positioning for Figure 225.
Figure 227 Lateral projection of skull with teeth shadows excluded for clarity.
A Atlas
B Stylohyoid bones
C Epihyoid bones
D Ceratohyoid bones
E Basihyoid bone
1 Incisive bone
2 Nasal bone
3 Maxilla or maxillary bone
4 Frontal bone
5 Parietal bone
6 Occipital bone
7 External occipital protuberance
8 External occipital crest
9 Interparietal process of occipital bone
10 Occipital condyle
11 Paracondylar process of occipital bone or jugular process
12 Petrous temporal bone or temporal bone-petrosal part
13 Tympanic bulla of temporal bone or temporal bone-tympanic part
14 External acoustic meatus of temporal bone
15 Zygomatic process of temporal bone or temporal bone-squamous part
16 Retroarticular process of temporal bone
17 Mandibular fossa of temporal bone
18 Masseteric border of zygomatic bone
19 Frontal process of zygomatic bone
20 Palatine bone
21 Vomer
22 Maxillary sinus of maxilla
23 Cribriform plate of ethmoid bone
23(a) Rostral limit
23(b) Caudal limit
24 Ethmoturbinates of ethmoid bone
25 Orbital margin
26 Frontal sinuses. Total of six: three on each side.
27 Dorsal nasal concha of ethmoid bone
28 Ventral nasal concha of maxilla
29 Lamina dura
30 Basisphenoid bone
31 Mandible
32 Mandibular body
33 Mandibular ramus
34 Coronoid process of mandible
35 Condyloid or articular process of mandible
36 Angular processes of mandible
37 Mandibular foramen
38 Mental foramen
39 Mandibular canal
39(a) Ventral border
40 Soft palate
41 Nasopharynx
Figure 228 Lateral projection of skull to demonstrate details of teeth excluded in Figure 227.
1 Upper incisors. Total of six.
2 Lower incisors. Total of six.
3 Upper canines. Total of two.
4 Lower canines. Total of two.
5 Upper premolars. Total of eight.
6 Lower premolars. Total of eight.
7 Upper molars. Total of four.
8 Lower molars. Total of six.
A Upper carnassial; 4th premolar
B Lower carnassial; 1st molar
Drawing only illustrates gross details of teeth as seen in radiograph, Figure 225. More detailed drawings are give in the section on dentition.
Figure 229 Line drawing of lateral projection of skull to demonstrate soft tissue shadows seen in radiograph, Figure 225.
External nose
1 Nostril
2 Nasal vestibule
3 Alar nasal fold
3(a) Bulbous terminal enlargement
4 Dorsolateral nasal cartilage
5 Straight nasal fold
6 Dorsal nasal meatus
7 Middle nasal meatus
8 Ventral nasal meatus
External ear
9 Pinna
10 Ear canals
The superimposed shadows, 9 and 10, of the external ear can be confused as bony abnormalities.
11 Skin fold level with dorsal aspect of orbits
Figure 230 Ventrodorsal projection of skull. Beagle dog 2.5 years old, entire male (same dog as in dorsoventral projection of skull, Figure 236). (Approximately 100% of original size.)
Figure 231 Line drawing of photograph representing radiographic positioning for Figure 230.
Figure 232 Ventrodorsal projection of skull with teeth shadows excluded for clarity.
A Atlas
B Axis
Hyoid apparatus. The bony shadows are indistinct but all are visible except for the basihyoid.
C Stylohyoid bone
D Epihyoid bone
E Ceratohyoid bone
F Thyrohyoid bone
1 Palatine fissure
2 Vomer
3 Maxillary teeth obscuring maxilla shadow
4 Lamina dura
5 Ventral nasal conchae and ethmoturbinates
6 Frontal sinuses
6(a) Frontal sinuses (lateral)
6(b) Frontal sinuses (medial)
7 Cribriform plate of ethmoid enclosing ethmoidal fossa
8 Medial wall of orbit
9 Border of choanae formed by palatine bone and pterygoid bone (hamulus seen as the more opaque shadow at caudal extremity)
10 Mandible
11 Mandibular body
12 Mandibular ramus
13 Coronoid process of mandible
14 Angular process of mandible
15 Condyloid or articular process of mandible
16 Temporal process of zygomatic bone
17 Zygomatic process of temporal bone
16 and 17 form the zygomatic arch.
18 Retroarticular process of temporal bone
19 Tympanic bulla of temporal bone-tympanic part
20 External acoustic meatus of temporal bone-tympanic part
21 Mastoid process of temporal bone-tympanic part
22 Jugular foramen of temporal bone-tympanic part
23 Paracondylar process of occipital bone or jugular process
24 Occipital condyle
25 External occipital protuberance
26 Nuchal crest of occipital bone
Figure 233 Line drawing to demonstrate teeth shadows excluded in Figure 232. Ventrodorsal projection of skull.
1 Lower incisor teeth. Total of six.
2 Upper incisor teeth. Total of six.
3 Upper canine teeth. Total of two.
4 Lower canine teeth. Total of two.
5 Lower premolar teeth. Total of eight.
6 Upper premolar teeth. Total of eight.
7 Lower molar teeth. Total of six.
8 Upper molar teeth. Total of four. (In this dog 2nd molar on left side is missing.)
A Lower carnassial; 1st molar
B Upper carnassial; 4th premolar
The drawing only illustrates gross details of teeth as seen in radiograph. More detailed drawings are given in the section on dentition.
Figure 234 Line drawing of ventrodorsal projection of skull to demonstrate soft tissue shadows seen in radiograph, Figure 230.
1 Nostril
2 Caudal limit of pinna
3 Internal folds of pinna
4 Vertical ear canal
5 Horizontal ear canal
6 External acoustic meatus
7 Neck skin fold
Figure 235 Schematic drawing of ventrodorsal projection of skull to demonstrate the temporomandibular joints and mandibular symphysis.
A Capsule of temporomandibular joint
B Lateral ligament
Between the cartilage-covered bony articulations is found an articular disc.
C Symphysis of mandible. (Fibrocartilage is seen as a radiolucent region in the radiograph.)
Figure 236 Dorsoventral projection of skull. Beagle dog 2.5 years old, entire male (same dog as in ventrodorsal projection of skull, Figure 230). (Approximately 80% of original size.)
Figure 237 Line drawing of photograph representing radiographic positioning for Figure 236.
Figure 238 Dorsoventral projection of skull with teeth shadows excluded for clarity.
A Atlas
B Axis
Hyoid apparatus. The bony shadows are more distinct than in the ventrodorsal projection. All bones are visible.
C Stylohyoid bone
D Epihyoid bone
E Basihyoid bone
F Ceratohyoid bone
G Thyrohyoid bone
1 Palatine fissure
2 Vomer
3 Maxillary teeth obscuring maxillary shadow
4 Lamina dura
5 Ventral nasal conchae and ethmoturbinates
6 Frontal sinuses
6(a) Frontal sinuses (lateral)
6(b) Frontal sinuses (medial)
7 Cribriform plate of ethmoid fossa
8 Medial wall of orbit
9 Border of choanae formed by palatine bone and pterygoid bone (hamulus seen as the more opaque shadow at caudal extremity)
10 Mandible
11 Mandibular body
12 Mandibular ramus
13 Coronoid process of mandible
14 Angular process of mandible
15 Condyloid or articular process of zygomatic bone
16 Temporal process of zygomatic bone
17 Zygomatic process of temporal bone
16 and 17 form the zygomatic arch.
18 Retroarticular process of temporal bone
19 Tympanic bulla of temporal bonetympanic part
20 External acoustic meatus of temporal bone-tympanic part
21 Mastoid process of temporal bonetympanic part
22 Jugular foramen of temporal bonetympanic part
23 Occipital condyle
24 Nuchal crest of occipital bone
Temporomandibular joints, single oblique projection with schematic drawing: Figures239–242
Figure 239 Rostrocaudal oblique (45-degree nose tilt) projection of temporomandibular joints. Doberman dog 7 years old, entire male. (Approximately 100% of original size.)
Figure 240 Line drawing of photograph representing radiographic positioning for Figure 239.
Figure 241 Rostrocaudal oblique (45-degree nose tilt) projection of temporomandibular joints.
A Temporomandibular joint of recumbent side
B Position of temporomandibular joint of non-recumbent side obscured by petrous temporal bones
1 Mandibular body
2 Angular process of mandible
3 Condyloid or articular process of mandible
4 Coronoid process of mandible
5 Mandibular fossa of temporal bone
6 Retroarticular process of temporal bone
7 Tympanic bulla of temporal bone
8 External acoustic meatus of temporal bone
9 Basisphenoid bone
10 Temporal process of zygomatic bone
11 Condyle of occipital bone
12 Atlas
13 Axis
14 Stylohoid bone
15 Epihyoid bone
16 Ceratohyoid bone
Figure 242 Schematic drawing of rostrocaudal oblique (45-degree nose tilt) projection of temporomandibular joints to demonstrate joint capsule and disc.
Joint capsule
Articular disc. Divides joint into ventral and dorsal compartments.
Laterally the joint capsule is strengthened to form a fibrous lateral ligament.
Tympanic bullae, relaxed lateral and oblique projections: Figures 243–248
Figure 243 Relaxed lateral (open mouth) projection of tympanic bullae. Beagle dog 2.5 years old, entire male. (Approximately 110% of original size.)
Figure 244 Line drawing of photograph representing radiographic postioning for Figure 243.
Figure 245 Relaxed lateral (open mouth) projection of tympanic bullae.
1 Tympanic bulla of temporal bone
1(a) Recumbent side (shaded in drawing)
2 External acoustic meatus of temporal bone
3 Zygomatic process of temporal bone
4 Temporozygomatic suture
5 External protuberance of occipital bone
6 External occipital crest
7 Occipital condyle
8 Paracondylar process of occipital bone or jugular process
9 Atlas
10 Axis
11 Mandible
12 Angular process of mandible
13 Coronoid process of mandible
14 Condyloid or articular process of mandible
15 Mandibular fossa of temporal bone
Note that 14 and 15 are superimposed, hence the temporomandibular joint is not demonstrated.
16 Retroarticular process of temporal bone
Hyoid apparatus
17 Tympanohyoid cartilage (seen as a radiolucent region between tympanic bulla and stylohyoid bone)
18 Stylohyoid bone
19 Epihyoid bone
20 Ceratohyoid bone
21 Basihyoid bone
22 Thyrohyoid bone
Figure 246 Rostroventral–caudodorsal oblique (open mouth) projection of tympanic bullae. Beagle dog 2.5 years old, entire male. (Approximately 100% of original size.)
Figure 247 Line drawing of photograph representing radiographic positioning for Figure 246
Figure 248 Rostroventral–caudodorsal oblique (open mouth) projection of tympanic bullae.
1 Temporal process of zygomatic bone
2 Zygomatic process of temporal bone
3 Mandibular body
4 Angular process of mandible
5 Condyloid or articular process of mandible
6 Vertical ramus of mandible
7 Retroarticular process of temporal bone
8 Temporomandibular articulation
9 Petrous temporal bone (seen as a radiopaque shadow)
10 Tympanic bulla of temporal bone (shaded in drawing)
10(a) External acoustic meatus (characteristic ‘lip’ at border of meatus which becomes larger with age)
10(b) Shadow formed by horizontal ear canal
11 Canal of auditory tube
12 Foramen magnum
13 Caudal edge of palatine bones or hard palate
14 Condyle of occipital bone
15 Atlas
16 Axis
17 Spinous process of axis
18 Dens or odontoid peg of axis
19 Stylohyoid bone
20 Epihyoid bone
21 Ceratohyoid bone
22 Basihyoid bone
23 Epiglottis
Dens or odontoid peg, single oblique projection: Figures 249–251
Figure 249 Rostroventral–caudodorsal oblique (open mouth) projection of dens or odontoid peg. Beagle dog 2.5 years old, entire male. (Approximately 130% of original size.)
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