154 
A. LIAUTARD. 
To be sure to penetrate to the cavities of the frontal fissures, trephining 
must be done upon a line a little superior to one which would unite the 
internal angles of both eyes. An opening made on one side of the me¬ 
dian line, penetrates on the corresponding sinus only; if both cavities 
are to be open, it is indispensable to trephine on each side of the median 
divisions, or to use a very large instrument, and apply it on the septum 
dividing the two sinuses. 
The bloodvessels are of little importance, as they generally are in 
median regions. Only small arteries, ramifications of the ascending ter¬ 
minal branch of the glosso-facial, and of the temporal arteries are found- 
the veins empty into the angular of the eye and the anterior auricular •’ 
t ie nerves come from the anterior auricular plexus. 
Differences.— In the ox, this region-ought to be called the frontal, 
as it is the bone of that name only which forms its skeleton, the parietal 
is ound further towards the base of the head. Much wider than in the 
torse, it occupies more than the two thirds of the anterior face of the 
lead, and descends down to a level of the anterior half; it also compre¬ 
hends the horns, whose form and dimensions vary considerably, accord- 
mg to the age, the sex and the breed of the animals. 
1 he horn rests upon a shorter bony rod, of same form and direction, 
fins rod is rough, perforated with holes, continued on the external sur¬ 
face by fissures, it is hollowed internally by cavities communicating with 
the sinuses of the anterior face. These surround the cranial cavity, in 
such a way that the trephining of the frontal in cattle always opens into 
these cavities, no matter on what part of the bone the operation is per¬ 
orated 1 hese sinuses are in connection with similar cavities of the 
parietal, occipital and sphenoid bones. They do not communicate with 
the superior maxillary sinus, but with the nasal cavities proper, by four 
foramina situated under the great ethmoidal volute. Girard was the first 
o see that three of these, communicate with peculiar sinuses, isolated 
from each other, and surrounding the orbits; he gave them the name 
In sheep and goats, that region is relatively smaller than in cattle - 
head Td TT’ the f r0ntal d ° eS n0 * reaCh aS far as the base of 
head, and the fissures do not extend beyond the superior border of the 
bone. 1 he horns may be absent, and in their place a kind of bony en- 
argement exists—if their are horns, they have a spiroid or cork-screwed * 
IncT pe< i 1 ' ‘ ar T S leep ’ the g0at carries the horns upwards and bent 
backwards and outwards. The form may vary considerably in the two 
