CHAPTER XX.
The Superior Cervical Ganglion.
With what it has Communication—Its Position—One of its Functions—Stimulation or Inhibition—Results Produced.
WITH WHAT IT HAS COMMUNICATION.
Every ganglion on the great chain of the sympathetic nerve has special and important functions, but upon the superior cervical falls the greatest burden of responsibility. This ganglion has communication with a greater number of nerves and organs than any other; is in direct communication with three cranial and four cervical nerves, indirectly with four more cranial nerves, and enters, by its branches into the formation of a large number of plexuses. Through this ganglion it is that much Osteopathic work is done, and the purpose of this brief paper is to point out some of the many effects which may be produced by its stimulation or inhibition.
ITS POSITION.
Anatomically we know that the superior cervical ganglion is situated in relation to the transverse processes of the upper three cervical vertebrae. It gives off branches which communicate directly with the vagus, glosso-pharyngeal and hypoglossal nerves; another branch, the ascending, passes into the carotid canal and enters into the formation of the carotid and cavernous plexuses; other branches pass to the pharynx, and a branch enters the formation of the cardiac plexuses. From the carotid and cavernous plexuses pass many nerves, only a few of which need special mention; one unites with the great superficial petrosal to form the Vidian nerve which goes to Meckel's ganglion, branches pass to the Gasserian ganglion, while we have others passing to the third, fourth, the ophthalmic division of the fifth and the sixth nerve, also we have derived from the nerve the sympathetic root of the lenticular ganglion.
ONE OF ITS FUNCTIONS.
Physiologically we know that one of the special functions of the sympathetic nervous system is to control the tone of non-striate muscular tissue, and that we have filaments distributed from the sympathetic system in the muscular wall of every blood vessel, duct and organ throughout the body. We also know that the sympathetic is the accelerator nerve of the heart, being opposed in its action by the vagus which, is inhibitory; further, that the vagus is constant in its brake-like action, while the sympathetic only acts when stimulated either directly or reflexly. While the vagus is inhibitory to the heart it is motor to the lungs. Nerve force is not generated in the sympathetic system; the cerebro-spinal nerve force is conveyed to the ganglia by the rami communicantes and in the ganglia is transformed into sympathetic nerve force. We might compare the ganglia to electrical transformers. Such being the case it is not difficult to see that if the superior cervical ganglion receives the nerve-force for transformation from the upper four cervical nerves and we can prevent, or lessen, the passage of nerve-force from the spinal cord through those nerves to the ganglion, that we will, to a corresponding degree, lessen the amount of sympathetic nerve-force transformed in the ganglion and transmitted from it by its branches.