830 NERVOUS SYSTEM OF THE HORSE 
branches derived from the anterior cervical ganglion. The ganglion gives off two 
or three filaments which subdivide to form the internal carotid plexus (Plexus 
caroticus internus) around the artery of like name. The cavernous plexus (Plexus 
cavernosus) surrounds the artery within the cavernous sinus and communicates 
with that of the opposite side. The external carotid plexus (Plexus caroticus 
externus) is formed around the homonymous artery, and filaments from it go to the 
vessel and its branches and to the salivary glands. 
2. The cervical part (Pars cervicalis s. sympathici) includes two ganglia and 
the trunk which connects them. 
The anterior or superior cervical ganglion (G. cervicale craniale) lies on the 
guttural pouch below the occipito-atlantal articulation (Fig. 562). It is reddish- 
gray in color, fusiform, and about an inch (ca. 2-8 em.) inlength. It is connected 
by rami communicantes with the last four cranial and first cervical nerves, sends 
branches to form the plexuses mentioned above, and contributes to the pharyngeal 
plexus. 
The cervical trunk of the sympathetic connects the anterior and posterior 
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661.—Lrrr Crrvico-rHorAacic GANGLION AND 
Fic. 660.—RicHr Crervico-rHorRacic GANGLION AND Fic. 
RELATED STRUCTURES OF Horse. 
RELATED STRUCTURES OF HORSE. 
G, G’, Ganglia; S, sympathetic trunk; V, vagus; G, G’, Ganglia; S, sympathetic trunk; V, vagus: 
R, recurrent nerve; N eardiac nerves, C.VIII, T.I., R, recurrent nerve; C.VII, C.VIITI, T.I, rami com- 
rami communicantes from eighth cervical and first thor- municantes from last two cervical and first thoracic 
N.tr., nervus transversarius; N.c., cardiac 
T.b., brachio- nerves; 
acic nerves; N.tr., nervus transversarlu 
cephalic trunk; A.d.c., dorso-cervical artery; A.b.d., nerves. 
right brachial artery; A.c.c., common carotid artery. 
cervical ganglia. On leaving the former it is associated in a common sheath with 
the vagus along the dorsal face of the common carotid artery. At the root of the 
neck it separates from the vagus and joins the posterior cervical ganglion. A?~- )- 
The posterior or inferior cervical ganglion (CG. cervicale caudale) is situated 
under cover of the first rib and the insertion of the scalenus (Figs. 660, 661). On 
the right side it lies upon the longus colli and the trachea, on the left side upon the 
same muscle and the cesophagus. It is flattened, very irregular and variable in 
outline, and is blended more or less with the first. thoracic ganglion, so that the two 
may be considered together as the ganglion stellatum. This receives at its antero- 
dorsal angle the nervus transversarius, which accompanies the vertebral artery 
in the canalis transversarius; it is a trunk formed by the rami communicantes of 
the cervical nerves except the first and last. Large rami connect with the last 
cervical and first and second thoracic nerves. Filaments also connect with the 
vagus. From the ventral part of the ganglion proceed the cardiac nerves now to 
be deseribed. 
1In some cases there exists a more or less distinet middle cervical ganglion which receives 
the filaments from the vagus and is-eonnected with the-pesterior cervical ganglion by a trunk. It 
occurs oftenest on the right side and gives mor two cardiac nerves. 
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