The Abdominal and Pelvic Brain
Byron Robinson, M. D.
ANATOMIC AND PHYSIOLOGIC CONSIDERATIONS.
The sympathetic rules the rhythm (peristalsis) of vascular canals
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
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.
ABDOMINAL BRAIN AND PLEXUS AORTICUS
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:
DUCTUS BILIS ET DUCTUS PANCREATIS ET AORTERIA HEPATICA
This illustration represents the binary and pancreatic ducts with the
hepatic artery, which are each ensheathed with a fenestrated network of
A H, hepatic artery; I, vateis diverticulum; TI, junction of ductus
cysticus and ductus hepaticus; III, ductus hepaticus; IV, cholecyst with
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
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
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.
NERVES OF THE HEART
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
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
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
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:
RENAL VASCULAR SUPPLY
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
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
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
3. The sympathetic branches preponderate in
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.
NERVES OF TRACTUS GENITALIS
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.