In =dorsal view= (Fig. 39) the skull presents a smooth convex surface,
broadest caudad, with the two =zygomatic arches= (_g_) curving out some
distance laterally. The following bones are visible in dorsal view: the
occipital (1), interparietal (2), parietals (3), temporals (4), frontals
(5), malar or zygomatic bones (6), nasals (7), maxillaries (8),
premaxillaries (9), and lachrymals (10).
[Illustration: FIG. 39.--SKULL, DORSAL SURFACE.
1, occipital bone; 2, interparietal bone; 3, parietal bones; 4,
temporal; 5, frontal; 6, malar; 7, nasal; 8, maxillary; 9,
premaxillary; 10, lachrymal, _a_, lambdoidal ridge; _b_, external
occipital tubercle; _c_, sagittal crest; _d_, parietal eminence; _e_,
line which forms the dorsal boundary of the temporal fossa; _f_,
zygomatic process of the frontal; _g_, zygomatic arch; _h_, frontal
process of the malar; _i_, supraorbital arch; _j_, nares; _k_, foramen
incisivum or anterior palatine foramen; _l_, sphenopalatine foramen;
_m_, zygomatic process of the temporal; _n_, infraorbital foramen;
_o_, opening of lachrymal duct.]
The caudal boundary of the dorsal surface is marked by the prominent
=lambdoidal ridge= (_a_) which passes from the middle cranioventrad
along each side to the root of the zygomatic arch: it is borne by the
occipital and temporal bones. From the middle of the lambdoidal ridge a
second ridge, the =sagittal crest= (_c_), passes craniad in the middle
line across the interparietal bone: it varies greatly in extent,
reaching in a very old and muscular cat to the cranial border of the
parietals, while in kittens it does not exist. The most prominent
portions of the skull in this region, just craniad of the middle of the
parietal bones, are known as the parietal tubercles or eminences (_d_).
A faint curved line (_e_) runs from the cranial end of the sagittal
crest craniolaterad to the base of the zygomatic process of the
frontal: it marks the dorsal boundary of the origin of the temporal
muscle, and may therefore be considered the dorsal boundary of the
temporal fossa. This fossa extends from its dorsal boundary as far
laterad and caudad as the lambdoidal ridge (_a_), and as far craniad as
a line connecting the tip of the zygomatic process of the frontal (_f_)
with the frontal process of the malar (_h_). The temporal muscle takes
origin from its surface.
The middle portion of the dorsal surface is formed by the frontals (5).
Each frontal presents laterally a prominent =zygomatic process= (_f_),
extending ventrolaterad toward a corresponding (frontal) process (_h_)
of the malar bone. These two processes mark the boundary between the
orbital fossa (craniad) and the temporal fossa (caudad). Craniad of the
zygomatic process of the frontal a sharp margin separates the dorsal
surface of the skull from the wall of the orbital fossa: this is the
=supraorbital arch= or margin (_i_).
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