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316 ANATOMY.
PharviiKeal
Pharvneeal and i ^ i
„
• '^ , - Superior lai'vnsieal. i
,
laryngeal, .- • " '
t
i
• = I ( Inlenor laryngeal. i
'
( Thoracico-cardiac.
Excranial
Thoracic, -^ Pulmonary.
\ciiitl.l
( Q^^sophageal.
f Hepatic.
Abdominal } Gastric.
( Intestinal.
The Atiricnlar Br
nerve, situated within the posterior laeerated foramen, and immediately
receives a connnunieating filament from the petrous ganglion of the
glosso-])liaryngeal nerve. It then passes backward behind the bulb of
the internal jugular vein, and enters a foramen near the base of the
styloid process of the temporal bone, which is situated to the inner side
of the a(jueduct of Fallopius. Within the canal it forms a communi-
cation with the facial nerve, after which it passes through a canal situ-
ated close to the internal auditory meatus between the tympanic and
mastoid processes of the temp(jral bone. At that point it emerges from
the Iwne, divides into two branches, the posterior division joining the
posterior anricular branch of the facial nerve, while the anterior division
is distributed to the integument and cartilage of the back of the ear
and tlie posterior and inferior portion of the auditory canal,
Vari(dion.s.—In rare instances the auricular branch of the pneumo-
gastric nerve is entirely absent, or it may have no communication with
the facial nerve. Occasionally its individuality is lost by uniting with
the facial nerve, in which case its fibres are distributed Avith the poste-
rior auricular branch of the facial.
The Jf('itliir/c((l Branch is quite small, and arises from the anterior
border of the superior ganglion of the pneumogastric. It passes
upward, and is distributed to the dura mater in the vicinity of the
posterior lacerated foramen.
Anadomotic Branches.—Tiie larger number of anastomosing branches
of the pneumogastric nerve are distributed to the circulatory, respira-
tory, and digestive systems. In the jugular foramen small branches
are given off to the dura mater and to the ear ; in the neck branches
are distributed to the jiharynx, larynx, and heart ; in the thorax
branches are supplied to the heart as well as the lungs and oesophagus;
in the abdomen its terminal branches are distributed to the stomach,
liver, and other organs.
The Phari/nr/ra/ Branches (Fig. 153) are the princi]ml motor nerves
of the ])harynx. They arc usually two in number, but there niav be more
than two; occasionally there is but one. They arise from the superior
and inner portion of the inferior or cervical ganglion of the pneumo-
gastric nerv'e, or, more properly, they are composed of fibres which come
from the accessory portion of the s])inal accessory nerve, which passes
over this ])ortion of tiie ganglion. They pa.ss downward and inward,
generally behind the internal carotid artery, but occasionally in front
of it, to the superior border of the middle constrictor muscle of the
pharynx, where they divide into numerous branches which interlace
