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



Our most cherished hopes are frequently maintained in silence.
The curfew tolls the knell of parting day - Thomas Gray (1716-1771), professor of modern history in the University of Cambridge, England.


    The proper nomenclature to apply to the sympathetic nerves is the nervus vasomotorius.  Practically it is a nerve belonging to the arteries.  In the anatomy of the nerves of the blood vessels two factors should be considered, viz.: (a) that nerves tend to course with blood vessels as the intercostals, nerves in the extremities, nerve coursing with the aorta and its branches.  However, cerebro-spinal nerves course mainly parallel with the vessels and divide mainly as acute angles, while vasomotor (sympathetic) nerves form a plexiform network, a neural meshwork, on the walls of the blood vessel, and are not confined to acute-angled dichotomy but divide and anastomose by angles of all dimensions; (b) the cerebro-spinal nerves in general do not form ganglia in their course along blood vessels.  The vasomotor nerve (sympathetic) forms ganglia, plexiform nodular meshwork on the walls of the arterial vessels especially at the bifurcation or point of exit of the arterial divisions.  The nervus vasomotorius courses along with the blood vessel as a nodularplexus, a leash woven like a web on the vessel wall. The coarser or finer web-like anastomotic meshwork of nerves surrounding a vessel is characteristic of the nervus vasomotorius (sympathetic).  With the development and differentiation of the animal life the nervus vasomotorius becomes distributed in its relation to blood vessels, dislocated, removed, transported along projecting lateral vessels from its direct contact with the original trunk vessel.  Excellent examples of removal - dislocation of the vasomotor nerve from contact with its original vessel - may be observed in the plexus aorticus, and especially in the instance of the plexus interiliacus where it is dislocated toward the median line from arteria iliacus communis. The second significant characteristic of the nervus vasomotorius is its numerous nerve ganglia found attached to the vessel wall and the location of marked ganglia at the bifurcation of trunk arteries as at the aortic bifurcations.  Ganglia of dimension also exist at the origin or exit of visceral arteries from the great arterial trunk as ganglion coeliacum (abdominal brain) ganglion spermaticum, ganglion renalis, ganglion arteriae phrenicae, ganglion mesentericum superior et inferior, ganglion cervicale (pelvic brain).  These significant ganglia located on the aorta at the origin or exit of visceral vessels, I shall term the aortic viscerel ganglia-ganglia aorticae viscerales.  The visceral aortic ganglion may have become dislocated from its vascular course during development, the most typical example of which is the ganglion cervicale, which was dislocated, transported medianward from the arteria iliaca communis to the lateral border of the uterus.  In the region of the origin of the coeliac axis, the arterial tripod, the ganglia have become dislocated, fragmented and removed, transported along adjacently developed arteries as the renal, mesenteric superior and inferior.  From fragmentation and transportation along arteries the renal arteries possess multiple ganglia.  In localities of the tractus vascularis where the vascular parietes are of maximum thickness, as the myocardium the ganglion cells collect in masses, known as cardiac ganglia.  We thus have the well-known cardiac ganglia of Ludwig (1816-1895), Bidder (1810-1892), Schmidt (1831-1894), Remak (1815-1865).  The nervus vasomotorius is an automatic nerve.  Ganglia located at the anastomosing points of nerves accompany its network of conducting coils throughout the entire course of the artery, thus automatically controlling each arterial segment.  The intimate relations of the nervus vasomotorius with the great arterial vessels may be sufficiently observed in the plexus aorticus thoracicus, plexus coeliacus (abdominal brain) plexus aorticus abdominalis, plexus interiliacus, plexus pelvicus (pelvic brain).  Ganglia of maximum dimension are located in intimate relation with the entire course of the aorta.  The nervus vasomotorius was originally essentially a vascular nerve, hence its name, nervus vasomotorius.  The nervus vasomotorius, vascular nerve plexuses, begin in ganglia (aortic visceral ganglion - ganglion coeliacum, spermaticum, mesentericum, renalis, cervicale), accompanies the arterial vessels as a plexiform nodular meshwork, a neural anastomosed vascular sheath, and ends in automatic visceral ganglia (Auerbach's, Meissner's, automatic menstrual, renal ureteral, vesical, etc., etc.), located in the parenchyma of organs.
    In general the dimensions of the ganglia on the arterial plexuses correspond with the dimensions of the vascular channel.  However, the renal arterial plexus is supplied with numerous ganglia of maximum dimension, relatively greater in proportion than that of the segments of the arterial channels as the myocardium.  The ganglia located on the arteries of the tractus genitalis are relatively numerous and of large dimension.  The original great abdominal vascular ganglion is that of the coeliac axis, from which doubtless many adjacent vascular ganglia have become fragmented, and transported on the vessels toward the viscera.  Perhaps the most typical example of this transportation of ganglia is the renal artery, on which is distributed relatively numerous small and large ganglia throughout its entire course.  A peculiar degenerative developmental process has occurred at the bifurcation of the aorta near the sacral promontory.  According to the general rule there should be a ganglion of large dimension located at the bifurcation of the aorta.  However, the nervous ganglion located in this region (which I term the interiliac nerve disc) has not only few ganglion cells (some deny the existence of any ganglion cell) but is dislocated distalward from the aortic bifurcation to the promontory of the sacrum.  It is mainly a dorso-ventrally flattened nerve disc with disappearing ganglion cells.
    The vascular nerve plexuses vary in dimension and fenestration.  The meshwork of nerves may be coarse or fine, wide or narrow.  The plexus aorticus abdominalis possesses ganglia, cords and fenestra of maximum dimensions.  The fenestra are extensive, elongated, formed by nerve cords of maximum dimension, on the anastomosing points of which are distributed ganglia of maximum dimension.  The plexus renalis is a wide-meshed network richly beset by large ganglia.  It is a plexus nervus vasomotorius possessing ganglia, cords and fenestra of maximum dimension.  The plexus mesentericus superior possesses numerous fine white cords with relatively large fenestra and ganglia limited in number and dimension.  This plexus possesses the peculiarity of the meshes or fenestra deviating considerably from the course of the artery.  The plexus hepaticus, composed of branches from the nervus vagus dexter and plexus coeliacus, surrounds the hepatic artery with strong,
flat cords in the form of a narrow-meshed network.  The plexus lienalis ensheath the arteria renalis and is bedecked with numerous ganglia of varied dimension.  Microscopic and macroscopic ganglia occur in the vascular plexuses.  Some macroscopic ones are constant, as the ganglion located on the external carotid artery.  Wrisberg's ganglion is situated in the cardiac plexus, notably the renal ganglia (macroscopic) are found on the plexus renalis.  In general the vasomotor nerves, sympathetic, form a plexiform nodular sheath around the blood vessels and enter with it into the substance of parenchyma of the organs.  This arrangement of the nervus vasomotorius induces many physicians to adopt the idea that the nervus vasomotorius originally and essentially belonged to the vascular system, and is lost on the coats of the arteries.  The nervus vasomotorius invariably accompanies the arteries - not the veins - the trunk of the vena portac being the only exception.  The ganglia of the nervus vasomotorius (sympathetic) are connected with the anterior primary divisions of the spinal by short nerve cords known as rami communicantes, which are gray and white in color.
    The gray rami communicantes arise in the ganglia of the nervus vasomotorius (sympathetic) and pass to the spinal cord.
    The white rami communicantes arise in the spinal cord and pass to the cords and ganglia of the nervus vasomotorius (sympathetic).  Hence the cerebro-spinal nerves and nervus vasomotorius (sympathetic) are distinctly and firmly anastomosed; however, like the federal, state, county and city government, possess many independent functions.


    The nervus vasomotorius consists of (a) the lateral chain and its ganglia; (b) the nerve plexuses and their ganglia accompanying the blood vessels from the aortic ganglia to the viscera; (c) the automatic visceral ganglia.  Hence the nervus vasomotorius of the abdomen consists of ganglion cells and nerve cords.  It must be remembered that it is not the number of ganglion cells that designates the power of a nervous system to accomplish maximum labor, but it is particularly the number of conducting cords associating and connecting the ganglion cells which decides the superiority of nervous executive ability.  The nervus vasomotorius is peculiarly rich in conducting cords, establishing rapid and frequent communication between its ganglion cells - governing every particular segment of the arterial channel.  The ganglion cells of the nervus vasomotorius are well informed from the rich association of connecting fiber transmitting news over many lines.  To illustrate the eternal vigilance of the nervus vasomotorius it need only to indicate the fact that the artery is always on tension, that the nerve is always on guard-awake or asleep.  A ganglion cell at each end of a conducting cord can accomplish more work than the single cord can transmit.  A depot at each end of a railroad line can handle more freight than a single road can transmit.  Increased number of conducting cords transmit increased information to the ganglion cells.  The nervus vasomotorius is partially independent, automatic in action.  If a frog's brain and cord be removed or destroyed the visceral functions will proceed for a time.  Circulation, respiration, digestion, which indicates that absorption, secretion and peristalsis, sensation remain intact.  The functions manifested by the blood vessels are: (a) peristalsis (rhythm); (b) absorption; (c) secretion; (d) sensation.  The plexiform nodular anastomosing neural network ensheathing the artery controls the above four functions.  The tractus vascularis contracts and relaxes with clock-like regularity.  Sensation is important from the fact that fluid in the vascular channel is required to produce normal vascular peristalsis.   Hence the rational idea in "visceral drainage" is to maintain sufficient volume of fluid in the vascular channel to stimulate and insure contraction.  It is the functions of the vascular plexiform neural sheath that is of peculiar interest to us.  From the fact that the heart will continue its peristalsis some time after removal indicates that the intramural cardiac ganglia are automatic.
    That the ganglia are located in the myocardium would indicate that the nervus vasomotorius terminates in the arterial parietes, and hence the contraction and dilatation of the heart are analogous to the contractions and dilatations of the arteries, being due to ganglia located in the vascular wall.  There is an intimate relation of the blood vessels within the substance of organs and the automatic visceral ganglia.  In general the origin of the nervus vasomotorius is the spinal cord - as there lies the vasomotor center, yet ganglia located on the aorta (e. g., abdominal brain) possess controlling influence.

Aortic Visceral Ganglia - Ganglia Aorticae & Viscerales.

    I wish to call attention in the function of the nerves vasomotorius to the ganglia located on the aorta at the exit of the visceral vessels.  I have termed them aortic visceral ganglia - ganglia aorticae viscerales - because they appear not only to influence visceral vessels, but the function of viscera, and to become, with differentiation and developmental processes, definitely associated with distinct individual visceral function, e. g., if one examines systematically in man and animals the arteria uterina ovarica during gestation, and in the resting state, a peculiar phenomenon will be observed.  The uterine artery will be enlarged, hypertrophied, exactly from its origin in the internal iliac, and the ovarian will be enlarged, hypertrophied exactly from its origin in the aorta, i. e., both uterine and ovarian arteries are enlarged, hypertrophied, from their exact origin in the arterial trunk.  Now the arteria uterina ovarica possesses distinct ganglia belonging to itself and the genitals.  In this case it consists of ganglion cervicale, or cervical ganglion (pelvic brain) dislocated from its original position located at the origin of the uterine artery.  In other words, through eons of ages the ganglia at the origin of the arteria uterina ovarica have become differentiated, developed into the power of endowing the artery supplying the genitals with function - gestation and menstruation - which requires a certain amount of blood.  Again, at the origin of the arteria mesenterica inferior is located a ganglion which irritates peristalsis in the left half of the colon - the faecal reservoir (left half of the transverse colon, left colon, sigmoid, and rectum) - peristalsis sufficient for a daily evacuation.
    In the tractus nervosus accompanying the tractus vascularis there are differentiations of nerve functions as, e. g., vasomotor dilator nerves and vasomotor constrictor nerves.  If vasomotor dilator nerves be stimulated relaxation and rest of the vessels of occur.  Hence these  nerves  have  been  termed  vaso-inhibatory  nerves,  e. g., stimulation  of  the  nervi eregentes proceeding from the plexus sacralis (due to accidental trauma of the spinal cord) will induce dilatation of the arteries of the penis with congestion of the corpora cavernosa and consequent partial erection.  Stimulation of the spinal cord induces priapism, i.e., pathologic conditions of the spinal cord may produce erection from stimulation.  The vasomotor constrictor nerves are in evidence when the surface of the body from fright or other cause become blanched, pale.
    Anatomically the cerebro-spinal nerves and nervus vasomotorius is distinctly and firmly anastomosed, connected, by the rami communicantes, however, like the federal, state, county and city government, the two systems of nerves perform many independent local functions.  Long ages of habitat established this function.

     Fig. 30.  This illustration presents two views, viz. : (a) The arterial trunks, arcs, arcades and circles of the tractus intestinalis are solidly and compactly anastomosed, connected through blood currents and channels. (b) The sympathetic nerve (nervus vasomotorius) accompanies the arteries as a plexiform network, as a nerve vascular sheath.  This cut demonstrates that the nerves of the tractus intestinalis are solidly and compactly anastomosed; hence irritation on any sympathetic plexus of the tractus intestinalis will effect, reflexly, all others. 10, arcs and arcades of the coeliac axis. 6, 7, 8 arcs and arcades of the superior and inferior mesenteric arteries, all of which are anastomosed united by (4), the pancreatico-duodenalis superior and inferior.  The arterial arcs, arcades and circles of the hand and utero-ovarian artery resemble those of the tractus intestinalis.  The number and dimensions of the arteries furnish a clue to the quantity of nerve supply.


     Fig. 31.  This illustration presents the sympathetic nerves following the arteries.  I dissected this specimen (man 40) with care, and from the model.  1 and 2, abdominal brain.  Splanchnicus major.  Ad, adrenal; Dg, ganglion (right), (left),  7. G. R. arteria renalis (right an renalia (left) Ur ureteral nerves.  S. G. and 5 mesentericum inferior; X, ganglionic coalescen ureteral crossing.  5 (Lowei) ganglionic coalescence of nerves at the crossing of the ureter and vasa iliaca communis.  ID, Plexus interiliacus (hypogastricus).  ID is the nerve disc of the sacral promontory.  The arteries are accompanied by a plexiform nodular neural sheath encasing the vessel.


     Fig. 32 represents typical Vascular Plexuses, which I dissected from a specimen taken from a subject of about fifty years of age.  I and 2 abdominal brain lying at the foot of the great abdominal visceral arteries.  P. 0. S. ganglia located at the other visceral arteries.  The nervus vasomotorius (sympathetic) accompanies the arteries in the form of a plexiform, fenestrated, neural sheath.