NERVOUS SYSTEM and SYMPATHETIC NERVE.
The nervous ganglions consist of a number of oval or roundish organs connected with certain nerves, and placed deeply in the tnmk of the body, to which they are confined, being situated, with the exception of those of the head, in the immediate vicinity of the vertebral column. Their number and size are subject to variation, not only in different persons, but even on the two skies of the same individual ; the following is the enumeration which approaches nearest to the truth : thirty on each side of the body, placed on the posterior roots of the spinal nerves; one on each side, situated on the larger origin of the fifth pair; the ganglions of the great sympathetic consisting of the follow ing, connected on each side of the body with what is regarded as the trunk of this nerve, viz. three cervical, twelve dorsal, three to four or live lumbar, three to five sacral ; to these we must add some large masses placed near the mesial plane, viz. two semilunar, three or four cceliac ganglions, and one cardiac ganglion, first de scribed by \Vrisberg, but which is occasionally deficient; and lastly, forming a part of the great sympathetic, the ophthalmic, the spheno-pala tine, the otic, and the submaxillary ganglions, and a small body usually met with in the carer nous sinus, the cavernous ganglion. M. Hip. Cloquet has described in rather vague terms a small reddish mass placed in the anterior palatine canal, which he calls the nuso-palatine ganglion; but Arnold, Cruvei!hier, and others deny, and with good reason, the existence of this body. A gangliform enlargement is con stantly seen on the commencement of the ner vus vagus, and a second lower down ; similar swelling is also placed on the glosso pharyngeal nerve (g. petrosum).
Professor Muller of Berlin has discovered above this enlargement a true ganglion on the the glosso-pharyngeal (ganglion jugulare nervi glosso-pharyngei), occupying half or two-thirds of the trunk of the nerve, and being precisely to that nerve what the intervertebral ganglion and the Gasserian are to the spinal nerves and the fifth pair. My colleague Mr. Walker has shown me this ganglion, which is placed in the upper part of the foramen lacerum basis cranii posterius, and corresponds to the above descrip tion.* Arnold has further noticed that at the junc tion of the superior twig of the Vidian nerve, or nervus innominatus, with the facial nerve, there is a gangliform swelling.t Mayer has discovered a minute posterior root of the sublingual nerve, with a ganglion on it, in some mamtnalia (ox, dog, pig), and in one instance in man.
Thus the total number of ganglions in the human body amounts to about one hundred and twenty-seven, exclusive of the ganglifurm enlargements on the pneumo-gastric, glosso pharyngeal, and the facial oerves.
These bodies have been variously arranged by writers on this subject ; thus by %Veber/ they are divided into ganglions of reinforce ment, such as those on the spinal nerves, and Into ganglions of origin, of which those of the sympathetic, the ophthalmic, and the splieno palatine are examples; whilst Wutzer,§ classing them according to their situation and relations, considers that there are three orders, I. the cerebral ; 2. the spinal ; 3. the vegetative : the first comprises the Gasserian ganglion, the ophthalmic, and the ganglion of Meckel, to which must be added the otic ganglion of Ar lipid ; in the second order are enumerated the thirty spinal ganglions and the ganglionic en largement of the nervus yaps and glosso-pha ryngeus ; in the third division are included the ganglions of the sympathetic nerve.
The former of these arrangements is objec tionable, because offices are assigned to the ganglions the existence of which has not been ascertained ; and the latter is so far erroneous that in this classification the ganglion of the fifth pair is separated from the spinal, to which it is undoubtedly similar; whilst the ophthalmic and spheno-palatine are as incorrectly divided from the system of the sympathetic.* In endeavouring to detect that which con stitutes the essential difference among these numerous bodies, we ought to pay special attention to the character of the nerves which are attached to the ganglions. Taking this as the only rational guide, I should refer them to two classes. 1. Those which are placed on sentient nerves, comprising the Gasserian, the ganglion of the glosso-pharyngeus, and the spinal ganglions The gangliform enlargement of the nervus vagus should be referred to this order, inasmuch as there can be little doubt, although this at present is not proved, that this nerve is compounded, like the spinal nerves, of motor and sentient fibrils, a surmise supported by the distribution of the vagus, and still more by the interesting discovery of my friend Mr. Solly, of the existence of certain motor fibrils in the exact part of the medulla oblon gata, whence this nerve arises.f 2. Those which have connected with them both motor and sentient nerves, and are, as I believe, always in relation with contractile and sensitive structures : I those, namely, of the great sympathetic nerve, comprising the cer vical, the dorsal, lumbar, and sacral, together with the cardiac, the semilunar and cceliac, also the ophthalmic, the spheno-palatine, the otic, submaxillary, and cavernous.