Page 264 - My FlipBook

274 ANATOMY. —
are all f^ituated near the median line, and as they pass out of the brain-
case there is reflected over them a prolongation of the dura mater, which
forms an enclosing sheath.
There are twelve pairs of cranial nerves. Anatomists have desig-

V\a. 185.

Dissection of the Sinuses of the Skull iiiul Cranial Nerves—the cavernous sinus dissected on tlie left
side; 1, third nerve; 2, optic nerve; :{, fourth nerve; 4, internal carotid artery; 5, (iasserian
ganglion of the fifth nerve, with its three divisions; fi, circular sinus; 7, superficial petrosal
nerve; 8, cavernous sinus; 9, sixth nerve; 10, transverse or basilar sinus; 11, seventh pair; 12,
superficial petrosal sinus: 13, eighth pair; 14, inferior petrosal sinus; Ifi, ninth nerve; 18, occip-
ital sinus ; 20, lateral sinus ; 21,torcular lleiophili.
nated them by numljers corresponding with their superficial origin,
beginning at the anterior pair and passing backward on the under or
anterior surface of the brain (Figs. 136 and 137). These nerves arc
known as motor nerves, sensory nerves, nerves of sjjecial sense, and
compound nerves. Their names and functions are as follows :

Number. Name. Function.
First pair . . . Olfactory Special sense, smell.
Second pair . 0{)tic Special sense, sight.
Third l)air . . Motor oculi ...... Motion to five orbital muscles.
Fdiirtli i»air . . Pathetic Motion to one orbital muscle.
Fiftii pair . . . Trifacial Sensation and mcUion, possibly special
sense —taste.
Sixth i)air . .\l)ducens Motion to one orbital muscle.
Seventh pair • Facial Motion to muscles of face.
Eif^lith pair . . Auditory Special sense, hearing.
Ninth jiair . . (Ilosso-pliaryngoal . . Sensation, motion, and special sense
taste.
Tentii pair . . Pneumogastric . . . Sensation and motion.
P^lcventh pair . S])inal accessory . Motion.
Twelfth pair . Hypoglossal .... Motion to muscles of tongue.
Nerves of Motion (or centrifugal nerves) are those which jireside ov^er
the action of the mu.'^clcs of tlie body. They have their origin in the