The Abdominal and Pelvic Brain
Byron Robinson, M. D.



The sympathetic rules the rhythm (peristalsis) of vascular canals and glandular
ducts of the body.

"The first questions to put to a witness are as to his name and place of residence, and his means of  knowledge of the facts concerning which he is expected to testify."
- Judge Charles B.Waite.

    After considerable microscopical investigation I am convinced that we do not know the whole sympathetic nerve, nor do we fully know its distribution because of its tenuity.  This remark is made as evidence gained in long microscopical labors on the peritoneum, in which I have been interested for years.  In the peritoneum we cannot tell the function of a nerve from its microscopical appearance.  We may assert that the width of the nerve indicates its length, that a wide nerve is a long nerve.
    Now a sympathetic nerve is a non-medullated nerve, i. e., the white substance of Schwann is lacking, at least it is not visible by our present optical instruments, or the present known reagents.  However, it appears to me to be present in Remak's bands (sympathetic fibers), though in an exceedingly thin layer.  Again, many nerves in the peritoneum begin with a medullary sheath and end without one.  The nerve is sheathed for part of its course and non-sheathed for another part.  But whether we are to call a nerve which is sheathed in its whole course or in a part of its course, a sympathetic or a non-sympathetic, depends upon whether it shows a different function.  In ordinary parlance a sympathetic nerve should have no visible sheath of Schwann, i. e., no medullary sheath.  A sympathetic nerve is perhaps better known by its function than by its microscopical appearance.  In fact no microscopist can decide merely by the appearance whether a nerve be sympathetic or non-sympathetic, unless he claim that all non-sheathed nerves are sympathetic.  For one can trace the medulla on a nerve in the peritoneum for a long distance when suddenly it disappears.  Should one meet this nerve unsheathed in any portion of the peritoneum, he could not decide upon its function.  At present we must discuss the function and not the microscopical structural differences.
    One of the best places to study the sympathetic nerves is in the peritoneum of the kitten (when about six weeks old).  The reagent best suited for practical microscopical work is as follows: Acetic acid 5 parts, gold chloride 1 part, and water 994 parts.  The rabbit's peritoneum is quite good, but not so good as the cisterna lymphatics magna of the frog's peritoneum.  Now it is not difficult to trace the gangliated cords lying on each side of the vertebral column.  In spare subjects the branches running from the cords and ganglia are plainly visible.  By a little care we can trace the branches of the ganglia and cords directly to the brain and spinal cord.  The sympathetic system lies in front of the cerebrospinal, as a secondary system enclosed in a cavity, the thoraco-abdominal, just as the cerebrospinal is enclosed in the cerebrospinal canal.  The sympathetic system is characterized by having non-medullated nerve fibers.  It frequently has large round ganglion cells enclosed in thick dense capsules.

     Fig. 52.  This illustration presents a limited amount of sympathetic nerves in outline.  (George Dancer Thane).

    The ganglion cells lie scattered over considerable areas, and are separated by dense, thick portions of connective tissue.  The ganglion cells of the sympathetic do not atrophy in early old age, as claimed by some, for before me lies a beautiful microscopical section of the abdominal brain of a woman who died at about the age of 72, in which the characteristic feature is the numerous large ganglion cells ensheathed in thick connective tissue capsules.  It may be that in some cases the superior cervical ganglion does develop an excess of connective tissue which crushes out the delicate ganglion cells, but such cases I have not observed in the abdominal brain, which must serve some great economic plan in the system.  The significance of the abdominal brain and sympathetic system must not be forgotten, as children are born without a brain, and some reports note the absence of the medulla also.  In such children the heart and viscera have been kept going by the sympathetic system.  Dr. W. F. Ball, of Mantua Station, Ohio, reoorted such a case to me.
    The sympathetic nerve is characterized by accumulations of cells at certain points, these being known as ganglia.  In the abdomen and chest the ganglia have a regularity of location corresponding to definite segments of the body.  There is a long chain of such ganglia situated on each side of the vertebral column, known as the lateral chain of sympathetic ganglia, and extending from the first cervical to the last sacral vertebra.  Two fine, small cords connect the spinal cord with each of the ganglia of the lateral chain, making a close and intimate relation of the spinal cord and lateral chain.  The spinal cord is doubly connected with the lateral chain.  The medullated branch passes from the anterior root to the ganglia.  The non-medullated root passes to the blood-vessels of the cord.  The lateral chain is well protected by adjacent bony structures from any injury or pressure by viscera.
    Ventral to the lateral chain there are located three nerve plexuses: one in the chest, the cardiac; one in the abdomen, the abdominal brain; and one in the pelvis, the utero-cervical, or as I prefer to call it, the pelvic brain.  The thoracic and abdominal plexuses are single, located in the ventral line of the body and possessed of a large amount of nervous ganglia and cells, especially the abdominal brain.  The pelvic plexus is double, situated on each side of the cervico-uterine junction, and is quite a massive collection of ganglia and nerve cells.  All three central plexuses, the thoracic, abdominal and pelvic, are bound by intimate and very close relations with the lateral chain of sympathetic ganglia.  Every viscus is profusely supplied with the sympathetic strands, and the vast number of cords and ganglia, like the equalizers on a horse power, hold in intimate relation all the viscera in a delicate balance.  Specialists are beginning to recognize the wonderful sympathetic balance of all the viscera, for when one gets out of order it untunes the chorus of the whole.  In fact, if a viscus in an adult is disturbed, it is generally the genitals, and if soon unbalances the remainder.  It is easy to note the large cords, the ganglia and the invertebral plexuses of the sympathetic system, to note their distribution and the relations of the ganglia to the viscera in spare subjects hardened by alcohol.  It is not difficult to see, even in rough, incomplete experiments, that there is a certain independence of the ganglia distributed to the viscera.  Though the latter are seen to be in close relationship with the great structure of the sympathetic, yet they show definite, independent action.  An hour after death one can induce the viscera in a dog to act by slight irritation or stimulation.  Perhaps little remains to be discovered concerning the arrangement of the, automatic ganglia in the viscera, or the structural arrangement of the cerebro-spinal and sympathetic systems.  But much remains to be discovered in regard to the functional relations of the cerebrospinal and sympathetic systems.  Each system may contain structures of the other, or not.  As a birdseye view of the sympathetic nervous system we may produce the following:

     Fig. 53.  This illustration represents the binary and pancreatic ducts with the hepatic artery, which are each ensheathed with a fenestrated network of sympathetic nerves. 
A H, hepatic artery; I, vateis diverticulum; TI, junction of ductus cysticus and ductus hepaticus; III, ductus hepaticus; IV, cholecyst with its duct.

    1.  A series of distinct ganglia connected by nerve cords, extending from the base of the skull to the coccyx.
    2.  Automatic visceral ganglia.
    3.  A series of three centrally located prevertebral plexuses. situated in
the thorax, abdomen and pelvis.
    4.  A series of communicating and distributing nerve fibers.
    The above propositions may be reduced to three elements, viz., nerve fibers and nerve cells, or ganglia and periphery.
    The caudal end of the sympathetic ends in a nerve mass known as the ganglion impar, and the head (frontal) end ceases in the ganglion of Prof. Francois Ribes of Montpelier, France (1800-1864).  I must confess that my searches for Ribes' ganglion have not been fully successful.
We find the sympathetic nervous system very widely distributed and it must not be considered improbable to find sympathetic centers in the cerebrospinal axis.  The seat of a ganglion may be anywhere and yet not partake of the adjacent surroundings, i. e., sympathetic ganglia may be situated in the cerebrospinal axis, yet not be an integral part of it, particularly as regards function.  Thus we may consider the vaso-motor center, the cardiac, and other centers, located in the medulla and cord, not to be a part of them.
    This view must hold as a fact, for blood-vessels which necessarily supply all parts of the body, brain or spinal cord, must be supplied with sympathetic nerves to regulate their caliber, but neither the nerves nor the blood-vessels are of the cord or medulla.  The sweat, heat (flashes) and vaso-motor (flushes) centers are located in the medulla and segments of the cord.  Pathologic states, as at the menopause, make all these centers painfully manifest.  Doubtless the genital center lies in the lumbar portion of the cord, though automatic visceral ganglia exist in the genital organs, such as I have formerly designated "automatic menstrual ganglia." Such ganglia require a month to accomplish a rhythmical cycle; they explode monthly.  In the spinal cord there exists a linear row of cells known as the columns of the late English investigator, Dr. Clark.  Some think that Clark's columns exercise the function of vaso-motor action, i. e., control the caliber of blood-vessels.  But as Dr. Fox states, this column of Clark's does not exist throughout the whole length of the cord.  Should further investigations demonstrate that Clark's columns have a vaso-motor function it would go a long way in proving considerable independence of the sympathetic nervous system.
    This independence, however, does not entirely depend on the supposed vaso-motor column of Clark.  Definite, though limited independence can be observed in portions of the sympathetic nerve by any one who will carefully perform experiments on the lower animals.  We of course do not overlook the idea that the sympathetic system and cerebrospinal system are so intimately co-related that one so blends with the other that all action seems lost in the cerebrospinal mass.
    When the spinal cord and brain have lost control of the intestines they assume a wild and disordered action, as may be seen in a person dying of brain disease.  In cases in which at the autopsy we could discover no brain disease I have found from one to four invaginations after death.   In such cases, doubtless, after the cessation of the function of the cerebrospinal masses, the sympathetic fell into a wild, confused and disordered action.  The muscular wall of the intestine assumed an irregular action producing invagination.  This latter is due to irregular action of the muscles in the intestinal wall.
    In a certain sense we may look at the nervous system as composed of two parts, viz.: a cerebrospinal part and a sympathetic part, connected by a number of single, fine, short, non-medullated strands.  These strands really connect the ganglia of the sympathetic with the brain and cord.  With such a constructed apparatus before us it might be stated that the sympathetic system simply consists of branches of the cerebrospinal system.  It may be represented as a branched roadway which distributes forces from the spinal cord to the viscera.  It may be considered as overflow paths to carry nervous energy to the periphery.  The ganglia of the sympathetic system are entirely outside of man's will-power.  He cannot control them to hasten visceral action or retard it.  It is plainly of utility to man to place beyond his willpower the action of viscera, as he would doubtless abuse it from selfish and other purposes.

     Fig. 54.  This figure represents the 3 cardiac sympathetic nerves on the left side to the heart (Nos. 34, 22, 22) ; 23 is Nrisberg's ganglion ; 18 is the phrenic joined to the inferior cervical ganglion at 8 by a branch, 19.   This connection explains the braying sound or expiratory moan on sudden rectal dilatation.

    But we must claim that the sympathetic nervous system is more than a mere branched roadway for the mere distribution of nervous energy from the cerebrospinal axis.  If nervous energy was merely to flow to the viscera from the cerebrospinal axis, why all this complicated, brain-like apparatus in the various sympathetic ganglia?  No, the ganglia of the sympathetic are centers of nervous energy, accumulations of brain cells, of reflex centers, organized receivers of sensation and transmitters of motion.  Is the cerebrospinal system closely related to the sympathetic system by mere relations of structure, because the sympathetic ganglia and cells are imbedded in the great centers, or is it because the cerebrospinal system has intrinsic and final control of the sympathetic?
    In the dorsal region we find the typical spinal nerve of the morphologist with its three chief divisions, viz.; (a) dorsal; (b) ventral and (c) visceral branch.  The visceral and vaso-motor branch is contained in the ramus communicans, which passes from the spinal cord to the lateral chain of the sympathetic or lateral ganglia, the demedullating centers.  From this lateral chain of ganglia nerves pass onward to a second chain of ganglia, known as the prevertebral or collateral ganglia, i. e., the cardiac, abdominal brain, inferior mesenteric and pelvic brain.  Milne Edwards called the nerves which pass from the lateral sympathetic chain to the collateral (prevertebral) chain, rami efferentes.  Again, from the prevertebral (collateral) ganglia or plexus, nerve fibers pass into smaller terminal ganglia in the abdominal organs, or to what we designate the automatic visceral ganglia.  We also have, besides the three distinct sets of sympathetic ganglia, connected with the ramus communicans, the posterior ganglia at the roots of the nerves as they issue from the spinal canal.  The ramus communicans is then connected with four distinct ganglia:

1.  The root ganglia (proximal ganglia), i. e., the ganglia situated on the posterior spinal nerves immediately after issuing from the cord.

2.  The lateral chain of sympathetic (proximal sympathetic ganglia).

3.  The prevertebral ganglia (distal sympathetic ganglia).

4.  The automatic visceral ganglia, or terminal ganglia (distal sympathetic ganglia).

    Leaving out the first of the ganglia, we note that the ramus communicans connects the spinal cords with three great systems of sympathetic ganglia, viz. : (a) the lateral chain (b) the prevertebral chain and (c) the automatic visceral ganglia, making a complicated and vast system distributed over a wide area.  In regard to the relation of this vast sympathetic system to the cerebrospinal axis in general, three views have been held:

     Fig. 55.  This illustration presents corrosion anatomy of 3 kidneys.  The renal vascular blades opened like a book. 
     The abundance of sympathetic nerves may be estimated by the fact that each branch of the renal artery is ensheathed by an anastomatic meshwork a fenestrated network of nerves.  The renal calyces and pelvis lie within the open book.  For nerves of the digestive tract see Fig. 13.

    1.  The first and perhaps the oldest view is that the sympathetic nervous system possesses a very great independence of action.  The supporters of this view make the sympathetic system the exclusive center of motion and sensation of the thoracic and abdominal viscera.  The chief establishers of this view are Volkmann (1842) and Bidder (1844).  Their able defense of the independence of the sympathetic nervous system is still entertained and published in the best anatomies.  Bichat (1800) advocates the independence of the sympathetic ganglia, as one of the first and ablest supporters.  In fact Bichat was one of the first to definitely conceive this notion.  Before me lies a rare old book which I secured from an old English collection.  It is written by James Davey, 1858, on "The Ganglionic Nervous System."  Davey gives Bichat credit for knowledge of the sympathetic ganglion.  Davey began to advocate the primary and essential independent function of the sympathetic in 1835. as is recorded in the "Lancet." Fletcher wrote (1837) on the independent action of the sympathetic.
    2.  The second view held was chiefly established by Valentine (1839).  This view makes the sympathetic system an offshoot or dependent of the cerebrospinal system.  It would contain no fibers except those in the brain and spinal cord.
    3.  A third view considers the sympathetic to be composed of fibers from the brain and cord, and also of other fibers which arise in the various ganglia.  According to this view every sympathetic nerve trunk contains both cerebrospinal and sympathetic fibers.  This view should consider all nerves sympathetic which arise in the ganglia and preside over the functions of the organs.
    The question might be asked, what are the functions of the sympathetic ganglia?  It should be remembered that many different opinions mean unsettled views.

    1.  We may state that the ganglia demedullate nerves.
    2.  More nerves pass out of a sympathetic ganglia than enter it; hence the ganglion is likely the originator of nervous fibers.
    3.  The ganglia possess nutritive powers over the nerves passing from them to the periphery.
    4.  They are centers of reflex action, i. e., receivers of sensation and transmitters of motion.

    We are therefore to consider as the subject of our theme:

    1.  The rami communicantes.
    2.  The lateral chain of sympathetic ganglia.
    3.  The prevertebral plexuses and
    4.  The automatic visceral ganglia.

    There are some differences between the sympathetic system and cerebrospinal axis which may be noted and discussed later.

    1.  We may claim that the sympathetic nerves are the visceral branches of the spinal nerves and hence have a distinct function, if not structure.
    2.  The individual fibers of the sympathetic nerves are of smaller caliber than those of the cerebrospinal or somatic nerves.
    3.  The sympathetic branches preponderate in non-medullated nerves.
    4.  The fibers of the sympathetic nerves are interrupted by nerve cells or
ganglia through which they pass.
    5.  Nerve cells are liable to accumulate into ganglia along a non-medullated nerve.
    6.  The sympathetic nerves tend to form closely meshed networks or plexuses, as Auerbach's and Billroth-Meissner's plexuses.
    7.  The somatic (cerebrospinal) nerves supply the body wall.  The sympathetic nerves supply the viscera.  In the visceral nerves must be included vascular nerves.

    We might call the various systems of ganglia of the sympathetic by numbers.  For example, the lateral chain of sympathetic ganglia may be called primary ganglia.  In the primary ganglia the chief nerves of the rami communicantes pass.
    Again, we might call the prevertebral plexuses, the secondary ganglia.  Many nerves from the rami communicantes enter the secondary ganglia without entering the primary ganglia.

     Fig. 56.  This illustration presents the nerves of the genitals according to Frankenhauser.

    Finally the automatic visceral ganglia might be called tertiary ganglia.  In short we could conveniently speak of the primary, secondary and tertiary system of sympathetic ganglia.
Much interest is attached to the ramus communicans, i. e., the narrow isthmus which joins the cerebro-spinal axis to the sympathetic system.  It is important to have a clear view of these rami communicantes, for through them pass the rami visceraes and rami vasculares, i. e., the rami communicantes contain and transmit the vascular and visceral nerves, both subjects of profound practical interest in medicine and surgery.
    In an anatomical sense writers understand by the term rami communicantes, two short nerves, a double connection between the cerebrospinal axis and the sympathetic system, i. e., with the lateral chain or primary ganglia.  One ramus communicans is white, medullated and passes directly out of the anterior root of the spinal cord chiefly to the lateral chain, but some fibers pass directly to the prevertebral plexus.  This branch of the communicans contains the visceral and vascular nerves; hence the importance to all practitioners.  The other ramus communicans is gray, non-medullated and passes from the lateral chain of ganglia to the spinal cord.  It is a vasomotor nerve, the purpose of which is to regulate the vessels of the cord and its meninges.  It is well to remember that the term ramus communicans is a general term including all the kinds of nerves which supply the viscera and blood-vessels.
    I propose here to consider at some length the ramus communicans which supplies the abdominal viscera and blood-vessels.  In the first place, there are certain fine, white, medullated nerves, as Gaskell has pointed out, which pass from the spinal cord, in the white ramus communicans between the second dorsal and second lumbar nerves inclusive, to supply the viscera and blood-vessels.  These nerves should be named as Gaskell suggests, splanchnics.  Hence we will have: (1) the thoracic splanchnics; (2) the abdominal splanchnics and (3) the pelvic splanchnics: A peculiar feature of these white rami communicantes is that they are only found in a limited region of the spinal column.  They begin, as Gaskell notes, at the second dorsal and end in the second lumbar.  They have a very fine caliber and pass into the lateral chain, where they become demedullated, and second into the prevertebral plexuses where the remainder become non-medullated.  Hence, all the white rami communicantes which pass through sympathetic ganglia leave the ganglia as non-medullated or as sympathetic nerves to attend to viscera and blood-vessels.  Above the second dorsal vertebra the rami cornmunicantes consist of the gray variety, i. e., they are peripheral nerves of the lateral ganglia.  Below the second lumbar vertebra they are also of the gray peripheral variety.