NERVOUS SYSTEM. 
125 
from the origin of this trunk to the temporal muscle, and a 
branch also runs along the upper border of the septum to the 
palate; and a larger branch, which traverses the palate in com¬ 
pany with its bloodvessels, passes through the foramen incisi- 
vum to the upper lip. 
The main trunk, of the nerve now enters into the superior and 
exterior foramen in the hiatus, between the palatine bone and 
the tuberosity of the superior maxillary bone, and which leads 
into a bony canal easily to be traced in the horse between the 
maxillary sinus and the antrum, and appearing as a great pillar 
passing through the palatine sinuses in the ox;—it traverses this 
canal, and at length emerges on the face, through the foramen 
infra orbitarium, and under the levator labii superioris. It no 
sooner escapes from this canal than it forms the pes anserinus, 
the goose’s foot;—it divides something like the foot of this bird! 
It anastomoses with, or receives numerous branches from, the 
seventh pair, and forms a strangely intricate plexus of nerves 
about the lower part of the face and muzzle, yet one wisely and 
beautifully contrived ; for here, as being the peculiar seat of 
touch, are required all the flexibility and more than the sensi¬ 
bility of the human hand. 
The Posterior Maxillary Nerve, or third Division of the Tri¬ 
geminus. —This escapes from the cranium through the foramen 
Jacerum basis cranii, and very soon gives off some important 
branches. 
The first Branch of the Posterior Maxillary, reckoning pos¬ 
teriorly, proceeds backwards below the condyle of the jaw, where 
it divides into two portions : the first runs up to the parotid 
gland, ramifies into many filaments, and unites with the seventh 
pair; it also dips deep into and principally supplies the temporal 
muscle, and penetrates into and is distributed through the mas- 
seter muscle. In this division there would seem to°be concen¬ 
trated the greater part of the motor fibrils of the trigeminus, for 
these are muscles of extensive and powerful action ; there are 
few muscles of the frame that are oftener or more powerfully 
employed than those which are concerned in mastication; but 
with the motor fibrils those of sensation are doubtless con¬ 
joined. 
The Second Branch is a long and slender one. It first dips 
into the pterigoideus muscle, and which is supplied by it,—con¬ 
sequently it is here also a motor nerve as well as a sensitive one : 
it then passes round or behind the tuberosity of the upper 
jaw, supplies the buccinator muscle possibly with sensitive 
fibrils alone, for others go to this muscle from the seventh 
pair. In the buccinator muscle these fibrils are usuallv lost but 
