Bones of the Skull Flashcards
(242 cards)
1
Q
What are the 3 functions of the bones of the skull?
A
- protection
- shape
- attachment
2
Q
What are the 3 things the skull is composed of?
A
- Neurocranium
- Viscerocranium
- Mandible
(neuro. & viscero. make up the cranium)
3
Q
What 3 parts of the brain do you look at in cases of rabies?
A
- Brainstem
- Cerebellum
- Hippocampus
4
Q
What 7 bones do you have to remove to see the entire brain?
A
- Occipital bone
- Sphenoid bone
- Temporal bone
- Frontal bone
- Parietal bone
- Interparietal bone
- Ethmoid bone
All of these bones comprise the neurocranium
5
Q
What are the 9 bones of the viscerocranium?
A
- Lacrimal bones
- Zygomatic bones
- Maxilla bone
- Incisive bones
- Palatine bones
- Vomer bones
- Nasal bones
- Pterygoid bones
- Dorsal & Ventral nasal concha
6
Q
What 4 bones make up the lateral walls of the nasal cavity?
A
- lacrimal bones
- zygomatic bones
- maxilla
- incisive bones
7
Q
What 4 bones make up the floor of the nasal cavity/ roof of the oral cavity?
A
- palatine bones
- maxilla
- incisive bones
- vomer
8
Q
What bone(s) make up the roof of the nasal cavity?
A
nasal bones
9
Q
The frontal and parietal bones are _% membranous and _% endochondral.
A
100% membranous- they cover the brain
0% endochondral
10
Q
Which 5 bones of the skull are 90% endochondral?
A
- ethmoid
- presphenoid
- basisphenoid
- exoccipital
- basioccipital
11
Q
The base and face of the skull are largely ______.
A
endochondral
12
Q
What is CVRL?
A
Crown Vertebral Rump Length;
how are fetuses aged using the skull
(measure from anterior fontanelle to the base of the tail while maintaining a midline and you can tell which trimester the fetus is in based on a formula)
the anterior fontanelle is usually 2x3 cm
13
Q
What is the fontanelle?
A
An opening in the middle of the skull that is expected to close. The time it takes to close varies between species.
#3
14
Q
Which fontanelle is larger?
A
the anterior fontanelle
14
Q
How many fontanelles are in the dog?
A
2 (anterior + posterior)
15
Q
What kind of joint are suture joints?
A
synarthrosis- fibrous, immovable
16
Q
Suture joints are prominent in ____ animals
A
young
17
Q
What kind of joint is the temporomandibular joint?
A
hinge, synovial with meniscus
18
Q
The individual bones of the skull are firmly united by _____
A
sutures
19
Q
The lower jaw (mandible) and the hyoid apparatus are attached to the skull by _____ joints
A
articular joints
20
Q
Identify the occipital bone:
A
21
Q
Identify the occipital condyle
A
22
Q
Identify the external occipital protuberance:
A
23
Q
Identify the jugular process (a portion is called the paracondylar process):
A
24
Where do the cervical muscles of the transversospinalis system attach?
at the jugular process, as well as the external occipital protuberance (just cervical mm.)
25
Is the occipital bone paired?
no
26
The occipital bone forms part of the ___ ___ ___.
caudal cranial vault
27
what is the name of the foramen in the caudal part of the occipital bone that the spinal cord exits the cranial vault from?
foramen magnum
28
The occipital condyle forms a synovial joint with the:
cranial articular fovea of the atlas (first cervical vertebra)
29
What is the small tract that opens onto the ventral surface of the occipital bone?
the hypoglossal canal. The hypoglossal nerve (CN 12) leaves the braincase through this structure
30
The external sagittal crest of the skull provides attachment for:
masticatory muscles
this is why it is more developed in heavily muscles breeds such as the Rottweiler and Pit Bull Terrier
31
Where is the nuchal crest?
running transversely at the caudal end of the external sagittal crest
32
The basilar part of the occipital bones forms the:
caudal part of the base of the cranium
33
ventral and dorsal surface of the basilar part of occipital bone- slide 17
34
The squamous part of the occipital bone completes the foramen magnum _____.
dorsally
35
What are the 2 landmarks for CSF collection?
- nuchal crest
- C1
36
Where do the nuchal ligaments attach?
at the external occipital protuberance
37
What bone forms a large portion of the lateral and dorsal aspects of the brain case?
the parietal bone
38
What 4 bones does the temporal fossa consist of?
- parietal bone
- temporal bone
- basisphenoid bone
- frontal bone
39
Identify the parietal bone:
40
What kind of muscles attach at the external sagittal crest?
muscles of mastication
41
Identify the temporal fossa:
42
Which bone forms part of the ventrolateral aspect of the brain base and houses the inner ear?
the temporal bone
43
What are the 3 parts of the temporal bone?
- Petrosal part (pars petrosa- mastoid process)
- Squamous part (pars squamosa)
- Tympanic part (pars tympanica)
44
Where does the trigeminal nerve enter the temporal bone via a canal?
at the petrosal part of the temporal bone
45
Do nerves enter or exit the skull?
exit
| Nerves originate in the brain.
46
What 2 nerves exit from the internal acoustic meatus?
- facial n.
- vestibulocochlear n.
47
Identify the canal for the trigeminal nerve in the temporal bone:
48
Identify the mastoid process:
49
Identify the internal acoustic meatus:
50
Identify the mandibular fossa:
51
Identify the zygomatic process of the temporal bone:
52
What 2 structures exit from the mastoid foramen?
- occipital artery
- emissary vein
53
What does the mandibular fossa of the temporal bone articulate with?
The condyles of the mandible to form the TMJ
54
What is the function of the retroarticular process?
to stop the mandible from moving caudally
55
The mastoid foramen is between which 2 bones?
the occipital bone and the temporal bone
56
The external acoustic meatus bridges the gap between the:
external and middle ear
57
In which 2 species are the petrosal and tympanic parts (also called the pyramid) of the temporal bone firmly fused into the squamous part?
carnivores and in the ox
58
What does the external acoustic meatus give attachment to(??)
annular cartilage of external pinna?
59
Which part of the temporal bone is the zygomatic part of?
pars squamosa
60
In which animals is the retroarticular process well developed?
in carnivores
61
The frontal bone forms part of the ____ of the skull.
dorsum
Also forms the dorsomedial part of the bony orbit
62
Which part of the temporal bone encloses the inner ear?
the petrosal part
63
Identify the ethimoidal foramen:
I
64
The rostral end of each frontal bone is characterized by the:
frontal sinus- an air-filled space
65
Identify the frontal bone:
66
Is the frontal bone paired?
yes
67
Identify the zygomatic process of the frontal bone:
68
The orbital ligament connects the __ to the __.
zygomatic process of the frontal bone to the frontal process of the zygomatic bone. this completes the canine orbit.
69
Identify the zygomatic bone:
70
Identify the frontal process of the zygomatic bone:
71
The paired frontal bones are situated between which 2 bones rostrally and caudally?
the nasal and parietal bone
72
What unites the 2 frontal bones?
the interfrontal structure
73
What are the 4 parts of the frontal bone?
- Frontal squama
- Orbital part
- Temporal part
- Nasal part
74
How does the zygomatic process articulate in ruminants?
it forms an osseous union with the frontal process of the zygomatic arch
75
How does the zygomatic process articulate in horses?
it forms an osseous union with the zygomatic process of the temporal bone
76
How does the zygomatic process articulate in carnivores?
it forms the caudal margin of the orbit with the orbital ligament
77
What is special about the orbital ligament in the cat?
it is ossified
78
in horned ruminants slide 36
79
What is the most complex bone of the skull?
the sphenoid bone
## Footnote
⮚ The sphenoid bone forms the rostral part of the base of the neurocranium
⮚ Consists of two similar segments:
⮚ The presphenoid
⮚ The basisphenoid
Sphenoid bone
Bones of skull, lateral view, zygomatic arch removed 39
Sphenoid complex
The sphenoid complex comprises two unpaired bones, the basisphenoid and presphenoid. The basisphenoid consists of a
midline body with two irregular wings extending dorsolaterad to form parts of the temporal and pterygopalatine fossae. The
smaller presphenoid is visible as a narrow median bone only on the ventral view, and its small wings are seen only from within
the braincase.
80
What are the 2 segments of the sphenoid bone?
- presphenoid
- basisphenoid
they are unpaired
81
slide 37
82
Identify the sphenoid complex:
83
Identify the palatine bone:
84
Identify the pterygoid bone:
85
Identify the sphenoid complec:
86
What muscle attaches to the pterygoid bone in cows/ ruminants?
87
What are the functions of the skull?
Protects brain and eyeballs, gives the head its shape, provides muscular attachment for eye muscles, muscles of mastication, and muscles of facial expression.
88
Surgeries associated with the head region are referred to as what?
Maxillofacial surgery or oral surgery.
89
The skull is a component of the ________ skeleton.
Axial.
90
What are the components of the skull?
Neurocranium (brain case), viscerocranium (facial bones), mandible (articulates at the base of the brain case), +/- hyoid bone.
91
What is the cranial vault?
The portion of the skull that is removed to allow access to the brain; dorsum of the skull/skull cap.
92
What is the clinical significance of the cranial vault?
Used in the case of suspected rabies when they need to access the brain to test for the disease.
93
What parts of the brain can be accessed by dissecting the temporal, frontal, and parietal bones?
Cerebellum, hippocampus, and brain stem.
94
What bones make up the neurocranium?
Occipital bone, sphenoid bone, temporal bone, frontal bone, parietal bone, interparietal bone, ethmoid bone.
95
What are the bones that make up the viscerocranium?
Lacrimal bone, zygomatic bone, maxilla bone, incisive bone, palatine bone, vomer bone, nasal bones, pterygoid bones, dorsal and ventral nasal concha.
96
What bones form the lateral walls of the nasal cavity?
Lacrimal bones, zygomatic bones, maxilla, incisive bone.
97
What bones form the floor of the nasal cavity/roof of the oral cavity?
Palatine bones, maxilla, incisive bones, vomer bone.
98
What bones make up the roof of the nasal cavity?
Nasal bones.
99
What are the tiny dots present on the lateral side of the bones of the skull?
Ossification centers.
100
What makes up the skeleton of the head?
A complex of bones that are composed of both membrane and cartilage; collection of smaller bones that fit together in a species-specific construction.
101
The bones of the skull are mostly __________.
Paired.
102
The frontal and parietal bones are of what origin?
100% membranous.
103
The 100% membranous nature of the frontal and parietal bones is the reason for what condition in newborns?
Soft skull/anterior fontanelle.
104
How are fetuses aged using the skull?
Crown Vertebral Rump Length (CVRL): measure from anterior fontanelle to the base of the tail while maintaining a midline and you can tell which trimester the fetus is in based on a formula.
105
Occipital, sphenoid, mandible, and ethmoid bones are of what origin?
90% endochondral.
106
The bones of the skull that are not entirely of endochondral or membranous origin have what origin?
50% membranous and 50% endochondral.
107
The hyoid bone and mandible articulate with what bone of the skull?
The temporal bone.
108
How is the hinge joint of the mandible formed?
The temporal bone has a mandibular fossa and condylar fossa that articulate with the mandible.
109
What bones form the floor of the neurocranium?
Basioccipital and sphenoid; serve as a chair where the brain sits.
110
What bones form the lateral walls of the neurocranium?
Temporal bones on either side.
111
What bones form the roof of the neurocranium?
Frontal bones, parietal bones, and interparietal bones.
112
What bone forms the nasal wall (rostral end) of the neurocranium?
Ethmoid bone.
113
What bone forms the nuchal wall (caudal end) of the neurocranium?
Occipital squamous.
114
What bones form the lateral walls of the viscerocranium?
Zygomatic, lacrimal, maxilla, and incisive bones.
115
What bones form the floor of the viscerocranium?
Palatine, vomer, incisive, and maxilla bones.
116
The bones that form the floor of the viscerocranium additionally form what structure?
Roof of the oral cavity.
117
What bone forms the roof of the viscerocranium?
Nasal bones.
118
The individual bones of the skull are firmly united via what?
Synarthrosis, fibrous sutures.
119
The lower jaw and the hyoid apparatus are attached to the skull via what?
Articular joints.
120
The joint between the parietal and frontal bones is called what?
Parietofrontal sutures.
121
The joint between the frontal and nasal bones is called what?
Frontonasal sutures.
122
The joint between the maxilla and incisive bones is called what?
Maxilloincisive sutures.
123
The joint between the temporal bone and parietal bone is called what?
Temporoparietal sutures.
124
Is the occipital bone paired?
No.
125
What is the significance of the occipital condyles?
Forms the 'yes' synovial joint with C1.
126
What lies in between both occipital condyles?
Foramen magnum.
127
What is the significance of the jugular processes/paracondylar processes of the occipital bone?
Attachment for some of the transversospinalis system.
128
What is the significance of the external occipital protuberance?
Sharp medial ridge that provides attachment for several muscles of the cervical region; intersection between the external sagittal crest and the nuchal crests.
129
What is the name of the 'spine' along the dorsum of the occipital bone?
External sagittal crest.
130
What are the ridges that project off of either side of the external occipital protuberance?
Nuchal crests.
131
What are the landmarks on the occipital bone for the collection of CSF?
Nuchal crest and C1.
132
What forms the squamous part of the occipital bone?
The dorsal to the lateral part along with the condyles; completes the foramen magnum dorsally.
133
What is the main bone that forms the roof of the neurocranium?
The parietal bone.
134
What forms the temporal fossa of the skull?
Parts of the frontal, parietal, and temporal bones, as well as a very small portion of the basisphenoid bone.
135
What structures cover the temporal fossa?
Covered by masticatory muscles that attach to the mandible.
136
What bone forms the ventrolateral part of the brain case and is where the inner ear is located?
Temporal bone.
137
What are the 3 parts of the temporal bone?
Squamous part, petrosa part, tympanic part.
138
What is the significance of the petrosa part of the temporal bone?
Internal portion of the bone that is the location of the canal for the trigeminal nerve, internal acoustic meatus, and jugular foramen.
139
What is the tympanic bulla?
Spheroid prominence on the temporal bone that encloses the air-filled space and forms part of the middle ear.
140
What is the zygomatic process of the temporal bone?
Part of the temporal bone that articulates with the zygomatic bone and has the mandibular fossa on its base.
141
What is the mandibular fossa?
Caudoventral base of the zygomatic process of the temporal bone that articulates with the condyle of the mandible to form the temporomandibular joint.
142
What components of the temporal bone form the zygomatic arch?
The zygomatic process of the temporal bone and the temporal process of the zygomatic bone.
143
What is the significance of the retroarticular process?
Prevents the mandible from shifting caudally.
144
What is the significance of the mastoid process?
Only part of the petrosa part of the temporal bone that is visible externally; provides attachment for the mastoid part of the cleidocephalicus muscle.
145
What is the mastoid foramen and what emerges from it?
Irregular opening between the occipital bone and the temporal bone along the suture line through which a branch of the occipital artery and the mastoid emissary vein come out of.
146
What are the characteristics of the external acoustic meatus?
Large opening that gives attachment for the annular cartilage of the pinna; covered in a live animal by the tympanic membrane.
147
What structure demarcates or forms a bridge between the external ear and middle ear?
Tympanic membrane.
148
What are the characteristics of the frontal bone?
Has sinuses called the frontal sinuses that communicate with the nasal cavity; forms the dorsomedial part of the orbit.
149
What is the significance of the zygomatic process of the frontal bone?
Supposed to articulate with the frontal process of the zygomatic bone to form the caudal boundary of the orbit, however it is absent in dogs and replaced by the orbital ligament.
150
What is the ethmoidal foramen?
Small foramen on the ventral border of the frontal bone that provides passage for random nerves and blood vessels as they travel to the nasal cavity.
151
What is the most complex bone of the skull that has a butterfly shape?
Sphenoid bone.
152
What are the two parts of the sphenoid bone?
Basisphenoid and presphenoid.
153
What does the presphenoid make up?
A portion of the optic canal.
154
What is contained within the basisphenoid bone?
Oval foramen, found foramen, alar canal.
155
Describe the articulations of the sphenoid bone.
Basisphenoid articulates with the basioccipital caudally; squamous part of the temporal bone articulates with the 'wings' of the sphenoid bone caudally; articulates with the parietal bone and frontal bone laterally; presphenoid articulates with the pterygoid bone on both sides.
156
What is a foramen?
A hole.
157
What is a meatus?
Opening that is wider on one end than the other; resembles a funnel.
158
What is a canal?
Tube
159
What is a fissure?
Two edges coming together to meet
160
What do cranial nerves do?
Exit the skull, not enter
161
What are the three branches of the trigeminal nerve?
Mandibular nerve, maxillary nerve, ophthalmic nerve
162
Where is the optic canal located and what nerves exit it?
Located on the sphenoid bone; optic nerve and internal ophthalmic nerve exit here
163
What is the difference between the ethmoid bone and the cribriform plate?
Ethmoid bone is the entire structure; cribriform plate is the area within the ethmoid bone with foramina
164
What passes through the numerous small foramina within the cribriform plate?
Olfactory nerves which innervate the olfactory epithelium
165
What passes through the major palatine foramen?
Major palatine artery, vein, and major palatine nerve
166
What is the major palatine nerve a branch of and what does it innervate?
Branch of the maxillary nerve; innervates the hard palate, gums, and salivary glands
167
Where is the minor palatine foramen located and what does it provide passage for?
Caudal to the major palatine foramen; provides passage for unspecified structures
168
What is the path of the minor palatine nerve and what does it innervate?
Wraps around the pterygoid muscle to innervate the hard and soft palates
169
How are the palates formed?
Palatine process of the incisive bone, maxilla bone, and palatine bone
170
What are the two portions of the palatine bone?
Horizontal and vertical
171
What is formed by the vertical portion of the palatine bone?
The border between the roof of the oral cavity and the nasal cavity called the choana
172
Where are the palatine fissures and what passes through them?
Two narrow foramina at the rostral part of the hard palate; provide passage for small arteries and incisive ducts
173
What is the role of the incisive ducts?
Connect the oral and nasal cavities
174
What is the first thing the trigeminal nerve passes through once it exits the brain?
The canal for the trigeminal nerve on the petrous part of the temporal bone
175
What happens to the trigeminal nerve once it passes through the canal for CN V?
Branches into maxillary, mandibular, and ophthalmic nerves
176
Describe the path of the maxillary nerve once it branches from CN V.
Passes through round foramen into the alar canal, gives off branches, and enters the maxillary foramen
177
What nerves exit the orbital fissure and what do they innervate?
Oculomotor, trochlear, ophthalmic, and abducens; innervate the extrinsic eye muscles
178
What nerves enter the periorbital region of the skull and what do they innervate?
Ophthalmic nerve and zygomatic nerve; innervate the lacrimal gland and lower eyelid
179
What passes through the oval foramen?
The mandibular branch of the trigeminal nerve
180
What happens to the mandibular nerve within the mandibular canal?
Gives off inferior alveolar nerve branches to innervate the roots of the teeth of the lower jaw
181
What happens to the caudal nasal nerve once it branches from the maxillary nerve?
Exits the sphenopalatine foramen to innervate Jacobson's organ
182
What passes through the caudal palatine foramen?
The major palatine artery on its way to innervate the hard palate, salivary glands, and gums
183
What happens to the maxillary nerve after it gives off the pterygopalatine branch?
Enters the infraorbital canal and gives off superior alveolar nerve branches
184
What is the maxillary artery a branch of and what does it supply?
Branch of the external carotid artery; supplies the upper jaw bone, maxillary sinus, teeth, and other facial structures
185
What does the fossa for the lacrimal sac lead into?
The nasal cavity
186
What is the orbital fissure formed by?
Sutures between presphenoid and basisphenoid bones
187
Why would we perform a maxillary nerve block?
Pain management or in place of general anesthesia in older patients
188
What are the 3 types of maxillary nerve block?
Rostral, caudal, sub-zygomatic
189
Describe the rostral maxillary nerve block.
Infraorbital approach; deadens from P3 to I1, upper lip and nasal region
190
Describe the caudal maxillary nerve block.
Insert the needle upwards by the last molar; deadens M3 to P3
191
Describe the sub-zygomatic maxillary nerve block.
Palpate the zygomatic bone and insert the needle beneath it dorsomedially; deadens all teeth of upper jaw
192
What is one mandibular bone referred to as?
Hemimandible
193
What are the different parts of the mandible?
Vertical part: ramus; horizontal part: body
194
What is the condylar process of the mandible?
Articulates with the mandibular fossa of the temporal bone
195
What is drop jaw caused by?
Nerve paralysis of the mandibular nerve and/or hypoglossal nerve
196
If the hypoglossal nerve was damaged along with the mandibular nerve, what clinical signs would you expect?
Tongue dangling out, causing the inability to swallow
197
What is used to try to prevent recurrence of mandibular dislocations?
Use a muzzle to keep the mouth closed for a while and liquid feeding
198
What does the mandibular nerve innervate?
Bottom teeth and gums
199
How many mental foramina are there?
At least one, sometimes additional accessory mental foramina
200
What is the landmark for a mandibular nerve block?
P1
201
What must be kept in mind when performing a mandibular nerve block?
Risk of not completely deadening the area if there are accessory mental foramina present
202
What is the landmark for a caudal mandibular block?
Midway between the angular process and the last molar
203
How is a caudal mandibular nerve block performed?
Insert needle 0.5-1 cm depending on the size of the dog once you locate the mandibular foramen
204
What must be taken into account regarding older animals and mandibular nerve blocks?
Older animals tend to have more deeply seated tooth roots
205
What structures exit/enter the jugular foramen?
Exit: CN 9, 10, 11; Enter: internal carotid artery and internal jugular vein
206
What structures enter the tympanooccipital fissure?
CN 9, 10, 11, internal carotid artery, and internal jugular vein
207
What nerves exit the internal acoustic meatus?
The vestibulocochlear nerve and the facial nerve
208
What happens to the facial nerve after it exits the internal acoustic meatus?
It exits the stylomastoid foramen
209
What is the hypoglossal canal?
The caudal-most opening at the base of the skull where the hypoglossal nerve leaves the brain-case
210
What are the choanae?
The caudal nares, openings from nasal cavity into the nasopharynx
211
What are the bony margins of the choanae formed by?
Contributions from the maxillae, vomer, and palatine bones
212
Describe the foramen lacerum.
Irregular foramen formed within the suture between the sphenoid complex and the temporal bone
213
Describe the ethmoidal foramen.
One or two small foramina near the ventral border of the frontal bone for the ethmoidal nerve
214
Describe the branching that results in the ethmoidal nerve.
CN V -> ophthalmic nerve -> nasociliary nerve -> ethmoidal nerve
215
What is the surgical landmark for ear surgery?
Mastoid foramen via the nuchal crest
216
What passes through the foramen magnum?
Spinal cord exits, vertebral arteries enter
217
What is the pterygopalatine fossa formed by?
Pterygoid bone and palatine bone
218
What is the significance of the lacrimal fossa?
Where the lacrimal sac lies and from which the nasolacrimal duct passes to the nasal cavity
219
Describe the foramen orbitorotundum.
Found in ruminants and pigs; fusion of the orbital fissure and foramen rotundum
220
What is the tentorium cerebelli osseum?
Process that comes off the parietal and occipital bone separating cerebrum and cerebellum
221
What is the rostral cranial fossa?
Area of the skull rostral to the optic canal where the cerebrum sits
222
What is the middle cranial fossa?
Area of the skull from the optic canal to the dorsum sellae turcicae where the pituitary gland sits
223
What is the caudal cranial fossa?
Area of the skull from the dorsum sellae to the foramen magnum where the cerebellum sits
224
Within what fossa does the pituitary gland sit?
Hypophyseal fossa
225
What is the vomer bone?
Ridge-like structure that separates the two choanae
226
What is the hamulus?
Tiny piece of bone projecting caudally off the pterygoid bone for muscle attachment
227
The external surface of the parietal bone can be divided into what two parts?
Parietal plane and temporal plane
228
What characterizes the internal wall of the parietal bone?
Vascular grooves and numerous depressions and ridges
229
The petrosal and tympanic parts of the temporal bone are fused in which animals?
Fused in carnivores and ox, separated in other domestic mammals
230
What portion of the temporal bone encloses the inner ear?
The petrosal part
231
The paired frontal bones are united by what?
The interfrontal suture
232
What are the 4 segments of the frontal bone?
Frontal squama, orbital part, temporal part, nasal part
233
Describe the species differences of the caudal margin of the orbit.
Ruminants: zygomatic process of frontal bone; horses: zygomatic process of temporal bone; carnivores: orbital ligament
234
Which portion of the frontal bone carries the cornual processes?
Caudal end of the frontal squama
235
What is the nasal part of the frontal bone bordered by?
Nasal bone rostrally and lacrimal bone laterally
236
Describe the orbital part of the frontal bone.
Forms the major part of the medial wall of the orbital cavity
237
What is the optic canal?
A feature of the sphenoid complex that transmits the optic nerve
238
What is the significance of the musculotubal canal?
Provides passage for the auditory tube from the middle ear to the nasopharynx
239
What is the significance of the caudal alar foramen?
The maxillary artery enters the sphenoid complex through this foramen
240
Describe how the mandibular foramen is used as a landmark for perineural anesthesia.
Horse/ox: medial surface center of line from condylar process to facial notch; dogs: medial surface two inches caudal to last cheek tooth
241
Describe how the mental foramen is used as a landmark for perineural anesthesia.
Horse: lateral surface of interalveolar margin; ox: lateral surface 1 cm ventral and caudal to canine; dog: middle of lateral surface ventral to first cheek tooth
