NEUROLOGY. 139 
communicates, either directly or indirectly, with the seventh, eighth, and 
ninth; in the cavernous sinus and orbital plexus with the third, fourth, fifth, 
and sixth; and even with the olfactory, optic, and auditory, by the fine 
filaments which accompany the nutrient arteries of those several organs in 
which these nerves expand and terminate; it also communicates, as has 
been already noticed, with the several ganglions in the head. In their 
course along the spinal column, each nerve regularly communicates with 
every pair of the spinal nerves, with each of the carvical nerves by one 
and sometimes by two filaments, and with each of the dorsal, lumbar, and 
sacral nerves by two, so that these nerves may be said to communicate with 
every nerve in the cerebro-spinal system. The sympathetic nerves have 
been considered by some as independent nervous systems, communicating 
by numerous branches with every portion of the cerebro-spinal system; by 
others they are regarded as nervous cords, formed by the union of branches 
from all the spinal and from several of the cerebral nerves: the latter is 
probably the more correct view. 
Although perfect symmetry does not exist between these nerves on the 
right and left sides, yet the differences are but trifling. The sympathetic 
nerves send off numerous branches, which are chiefly destined to supply 
the heart and the coats of the great vessels, and all the pelvic and abdo- 
minal viscera, except the stomach. These branches arise from the gan- 
glions on these nerves; of these there are generally three in the neck; in 
the back and loins they correspond’ with the number of vertebree in those 
regions, and in the pelvis there are three on each side, and the coccygeal 
or impar ganglion below. 
The cervical ganglions are three, the superior, middle, and inferior. 
Sometimes, however, there are four, and at others only two. 
The superior cervical ganglion is of an oval figure and reddish color, 
extending from the first to the third cervical vertebra; its upper end is 
very small, and about half an inch beneath the carotid foramen in the 
petrous bone. It sends off several branches, superior, inferior, internal, 
external, and anterior. The superior branches are two in number; they 
ascend in the carotid canal to the cavernous sinus, and communicate with 
the sixth and the vidian branch of the fifth. In the carotid canal they form 
the internal carotid plexus, from which some filaments pass through the 
petrous bone into the tympanum. In this sinus, the ascending small fila- 
ments again form a plexus named cavernous plexus. From this plexus, 
filaments pass to the Casserian ganglion, others to the orbital plexus and 
lenticular ganglion, and the remainder accompany the artery to the brain. 
The wferwor or descending branch is the continued cord of the sympathetic 
itself which joins the middle or cervical ganglion. The anterior branches 
are numerous; some communicate with the eighth and ninth in the great 
basilar plexus, others surround the external carotid, and divide into fasci- 
culi which accompany all its branches and form loops and plexuses around 
each, named from their destination, thyroid, lingual, &c. The eaternal 
branches jon the superior cervical nerve; they are large and ganglionic. 
Some join the nervous loop, the principal unite with the second cervical 
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