CEREBRO-SPINAL NERVES. 371 
the first pair are the olfactive, which proceed from the bulbs 
(1) of the olfactive peduncles, into the cavity of the nose. 
Next to these are the optic nerves (2), which may be partly 
traced to the optic ganglia, and 
y to the thalami optici, The 
third (3), fourth (4), and sixth pairs 
(6), are nerves of motion only, and 
are distributed to the muscles of 
the eye. The fifth pair is for the 
most part a nerve of sensation 
only. Before leaving the skull, it 
divides into three great branches ; 
of which the first (5) passes into 
the orbit (or cavity in which the 
eye is lodged), endows the parts 
contained in it with sensibility, 
| and then comes out beneath the 
eyebrow, to be distributed to the 
forehead and temples ; the second 
(5’) passes just beneath the orbit, 
-and makes its way out upon the 
‘face, supplying the cheeks, nose, 
upper lip, &c., which it endows 
with sensibility ; whilst the third 
(5”), which (like the spinal nerves) 
possesses a motor root also, supplies 
the muscles of mastication with 
the power of moving, and the 
parts about the mouth with sensi- 
bility. The seventh pair (7), or 
facial, is the general motor nerve 
of the face; and this does not 
endow the parts which it supplies 
BB2 
1 a U7) 
J 
Fig. 197.—Brain anp Spina 
Corp oF May. 
t rve of hearing. At 9 is seen the glosso-pharyngeal nerve, 
Originating from the 
per part of the spinal cord (or medulla bloongata) very near 
