_I_, Occipital; _II_, tympanic part of temporal; _IIa_, squamous part
of temporal; _IIb_, mastoid part of temporal; _III_, sphenoid; _IV_,
pterygoid; _V_, palate bone; _VI_, vomer; _VII_, malar; _VIII_,
zygomatic arch; _IX_, inner wall of orbit; _X_, palatine process of
maxilla; _XI_, premaxilla; _XII_, orbital cavity; _1_, _1_,
tubercles above foramen magnum; _2_, foramen magnum; _3_, occipital
condyle; _4_, notch between occipital condyles; _5_, condyloid
fossa; _6_, hypoglossal foramen; _7_, paramastoid (styloid, jugular)
process; _8_, for. lacerum and posterior opening of carotid canal;
_9_, petro-occipital synchondrosis; _10_, petro-tympanic fissure;
_11_, tubercle; _12_, bulla ossea; _13_, muscular process of
petrous; _14_, carotid foramen; _15_, osseous Eustachian tube; _16_,
postglenoid process; _17_, glenoid cavity; _18_, for. ovale; _19_,
posterior opening of alar canal; _20_, external opening of
parieto-temporal canal; _21_, stylo-mastoid foramen; _22_, external
auditory meatus; _23_, temporal crest; _24_, zygomatic process of
temporal bone; _25_, body of postsphenoid; _26_, body of
presphenoid; _27_, anterior opening of alar canal; _28_, for.
lacerum orbitale; _29_, optic foramen; _30_, hamulus of pterygoid;
_31_, horizontal part of palate bone; _32_, perpendicular part of
palate bone; _33_, median palatine suture; _34_, palato-maxillary
suture; _35_, posterior nasal spine; _36_, anterior palatine
foramen; _37_, palatine groove; _38_, alveolar border of maxilla;
_39_, palatine process of maxilla; _40_, pterygoid process of
maxilla; _41_, palatine fissure; _42_, body of premaxilla; _43_,
palatine process of premaxilla; _44_, alveolar border of premaxilla;
_45_, supraorbital process of frontal bone. (Ellenberger-Baum, Anat.
d. Hundes.)
]
The =occipital bone= is similar in position to that of the horse. The
crest, is prominent, angular, and directed backward. Just below the
crest are two rough imprints or tubercles for muscular attachment. The
surface below these is convex from side to side and concave from above
downward. On either side, at the junction with the squamous, there is a
foramen which communicates with the parieto-temporal canal. The condyles
are somewhat flattened and are widely separated above; at the inner side
of each is a short condyloid canal, which opens into the
parieto-temporal canal. The paramastoid processes are very short. The
basilar part is wide and joins the bulla ossea on either side; its lower
surface is flattened and the tubercles are at the junction with the
bulla. The hypoglossal foramen is small and is close to the foramen
lacerum posterius; the latter is bounded in front by the bulla ossea,
behind and internally by the occipital bone.
The =interparietal bone= fuses with the occipital before birth. It forms
the high posterior part of the sagittal crest, and is wedged in between
the two parietal bones. The tentorium osseum is thin and curved, concave
ventrally. Its base concurs with the occipital and parietal bones in the
formation of a transverse canal which is continuous with the
parieto-temporal canals.
[Illustration: