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THE JSERVOUS SYSTEM. ; 305
posterior cranial nerves, and by so doing increases the functional power
of some of these nerves.
The following are some of its communicating branches :
It communicates with the three divisions of the tiftli nerve
With the spheno-palatine, submaxillary, and otic sympathetic ganglia
;
A branch to the auditory nerve
A branch to the glosso-pharyngeal nerve
;
Through its auricular branch it also conununicates with the pneumo-
p-astric nerve. It will be seen that through this lars^e communication it
supplies other structures, which will be described hereafter.
The superficial or apparent origin of the facial nerve is from the
uppermost lateral portion of the medulla oblongata in a groove between
the olivary and restiform bodies, just below the pons varolii. The eighth
or auditory nerve is in close apposition to its outer side, the two being
separated only by a couple of filaments which are known as the inter-
mediary nerve of Wrisberg (portio inter duram et mollem).
This intermediary nerve is more or less connected with the facial and
auditory nerves, but from the fact of its greater connection with the
facial it has been classed as one of its roots (accessory root of Sappey).
It passes between the two nerves into the internal auditory meatus, and
terminates in the geniculate ganglion.
The facial nerve passes from its origin, in company with the eighth
or auditory nerve, forward and outM-ard between the pons varolii and
the middle peduncle of the cerebrum, around which it curves to enter
the internal auditory meatus, situated in the posterior surface of the
])etr6us portion of the temporal bone. It rests in a groove on the
upj)er part of the meatus, the auditory nerve being below, while the
nerve of Wrisberg still retains its position between the two. On reach-
ing the upper extremity of the meatus, the seventh nerve passes into and
through the aqueduct of Fallopius. This aqueduct runs an extremely
tortuous course through the petrous portion of the temporal bone. It is
at first directed outward for a short distance between the cochlea and the
vestibule to the wall of the middle ear ; then it b^nds backward over
the fenestra ovalis, then downward behind the pyramid and the middle
ear, and terminates at the stylo-mastoid foramen, at which point the
nerve makes its exit on the face. It passes from this point downward
and forward in the substance of the parotid gland, and breaks up into
numerous branches to supply the muscles of expression.
The branches of the facial nerve are tabulated as follows bv Prof.
Allen : ^
The great superficial petrosal nerve.
f " "
j The lesser "
Branches of the geniculate ganglion, | Branches to the sympathetic system.
six in number, 1 " " tympanic plexus.
"
I " pneumogastric nerve.
" " glosso-pharyngeal nerve.
[
Stapedius.
f
Before escaping at the stylo-mastoid ] (chorda tympani.
foramen, I Connecting branches with pneumogastric.
" " " glosso-pharyngeal.
[
^Allen's Anatomy, p. 529.
Vol. I.—20
THE JSERVOUS SYSTEM. ; 305
posterior cranial nerves, and by so doing increases the functional power
of some of these nerves.
The following are some of its communicating branches :
It communicates with the three divisions of the tiftli nerve
With the spheno-palatine, submaxillary, and otic sympathetic ganglia
;
A branch to the auditory nerve
A branch to the glosso-pharyngeal nerve
;
Through its auricular branch it also conununicates with the pneumo-
p-astric nerve. It will be seen that through this lars^e communication it
supplies other structures, which will be described hereafter.
The superficial or apparent origin of the facial nerve is from the
uppermost lateral portion of the medulla oblongata in a groove between
the olivary and restiform bodies, just below the pons varolii. The eighth
or auditory nerve is in close apposition to its outer side, the two being
separated only by a couple of filaments which are known as the inter-
mediary nerve of Wrisberg (portio inter duram et mollem).
This intermediary nerve is more or less connected with the facial and
auditory nerves, but from the fact of its greater connection with the
facial it has been classed as one of its roots (accessory root of Sappey).
It passes between the two nerves into the internal auditory meatus, and
terminates in the geniculate ganglion.
The facial nerve passes from its origin, in company with the eighth
or auditory nerve, forward and outM-ard between the pons varolii and
the middle peduncle of the cerebrum, around which it curves to enter
the internal auditory meatus, situated in the posterior surface of the
])etr6us portion of the temporal bone. It rests in a groove on the
upj)er part of the meatus, the auditory nerve being below, while the
nerve of Wrisberg still retains its position between the two. On reach-
ing the upper extremity of the meatus, the seventh nerve passes into and
through the aqueduct of Fallopius. This aqueduct runs an extremely
tortuous course through the petrous portion of the temporal bone. It is
at first directed outward for a short distance between the cochlea and the
vestibule to the wall of the middle ear ; then it b^nds backward over
the fenestra ovalis, then downward behind the pyramid and the middle
ear, and terminates at the stylo-mastoid foramen, at which point the
nerve makes its exit on the face. It passes from this point downward
and forward in the substance of the parotid gland, and breaks up into
numerous branches to supply the muscles of expression.
The branches of the facial nerve are tabulated as follows bv Prof.
Allen : ^
The great superficial petrosal nerve.
f " "
j The lesser "
Branches of the geniculate ganglion, | Branches to the sympathetic system.
six in number, 1 " " tympanic plexus.
"
I " pneumogastric nerve.
" " glosso-pharyngeal nerve.
[
Stapedius.
f
Before escaping at the stylo-mastoid ] (chorda tympani.
foramen, I Connecting branches with pneumogastric.
" " " glosso-pharyngeal.
[
^Allen's Anatomy, p. 529.
Vol. I.—20
