Studies in the Osteopathic
Basic Principles: Volume
Louisa Burns, M.S., D.O., D.Sc.O.
THERE ARE CERTAIN POINTS UPON THE SURFACE OF THE BODY
WHOSE MANIPULATION AFFECTS VISCERAL ACTIVITY.
These points have been called “centers” for the functions regulated through
their intervention. Physiologically, the term “center” is applied
to a group of nerve cells wherein any function is regulated. The
use of the same term in reference to points upon the surface of the body
is not defended, but the term has become so well fixed in usage that it
is perhaps better to continue its use than to add another term for the
superficial centers are very closely related with the nerve centers, and
owe their effectiveness to that relation. The nerve centers control
the activity of certain organs by coordinating the nerve impulses received
from the sensory nerves of those organs, from other tissues associated
with these in structure or function, and from higher centers in the brain.
The vaso-motor center, for example, is affected by sensory impulses from
the heart, by sensory impulses from all over the body, by descending impulses
from the basal ganglia, etc.
Regulation of Nerve Centers.
nerve cells of these centers are affected by changes in their environment,
as are other living cells. The respiratory center, for example, is
stimulated by increasing venosity of the blood flowing through it; the
heart center is affected in the same way. Both of these centers are
subject also to the stream of sensory impulses which are continually being
carried to them. All of the other nerve cells of the body are also
affected by the quality of the blood flowing through them.
nerve centers are affected continually by the nerve impulses reaching them
from all other parts of the body in structural relationship with them.
The action of the nerve centers, and therefore the action of the structures
controlled by them, depends upon the character of the sensory impulses
reaching the center. In other words, the action of any given center
represents the algebraic sum of the nerve impulses reaching that center.
If we wish to affect any function, then, we may do so if we can affect
the character of the nerve impulses reaching the group of nerve cells controlling
groups of nerve cells are placed well within the nervous system, and inclosed
in a bony case, hence any direct methods of affecting them are out of the
question. The pathway of impulses from the center to the structure
innervated may be directly affected in many cases, as, for example, in
the case of the vagus and phrenic nerves, the cervical sympathetic ganglia,
the nerve centers act in accordance with the algebraic sum of the impulses
reaching them, it is possible for us to affect their action indirectly
by changing the character of the impulses sent to them. This is done
by means of appropriate manipulations of certain superficial areas called
centers, also. Unfortunately, the term center is thus applied both
to the group of nerve cells and to the superficial area which is in closest
functional relationship with it.
Demonstration of Superficial Centers.
superficial centers were first recognized by clinical experience.
Afterward, they were demonstrated by experiments upon animals and persons.
evidence has been somewhat inexact, as clinical evidence always must be,
since patients nearly always suffer from so many and such complicated abnormal
conditions. In cases of long standing every abnormal effect is itself
a cause of other abnormal conditions, and these in turn result in yet other
malfunctions, and so on. For this reason, the evidence afforded by
observations upon patients has not been so satisfactory in isolating the
individual centers as it has been in demonstrating the success of the therapeutic
Areas of Hyperesthesia.
existence of hyperesthetic areas and of abnormal muscular contractions
in the neighborhood of the roots of the nerves supplying organs of disordered
function was first a matter of clinical observation, and later a
matter of experimental demonstration. In clinical experience, the
relief of the muscular contractions and of the hyperesthesias was found
to be followed by some relief of the symptoms noted. This relief
was only temporary in some cases, but in acute disorders, and in cases
wherein the muscular contraction was the chief factor in perpetuating the
abnormal function, the relief secured by relieving the muscular tension
and the hyperesethesia was permanent. These cases, whether acute
or chronic, and whether the relief were temporary or permanent, proved
the existence of a central relationship between superficial areas and viscera.
was also found that slight malpositions of the ribs and vertebrae were
usually found present in the neighborhood of the roots of the nerves supplying
the affected organ. The osteopathic conception of the relation of
slight mal-positions of bones and articular structures to the malfunction
and disease of the various tissues of the body was thus determined.
The fact that the correction of the mal-positions as found was followed
by a decrease in the severity of the disease symptoms, and in many cases
by either a symptomatic or an absolute recovery, established the relation
of cause and effect beyond a reasonable doubt.
Physiology of Superficial Centers.
existence of the osteopathic or superficial centers depends upon the fact
that all structures innervated from any segment of the spinal cord are
affected by all sensory impulses reaching that segment. Because of
this physiological relationship, the viscero-sensory impulses initiate
impulses to the skeletal muscles innervated from the same and adjoining
segments of the cord, as well as to the viscera innervated from the same
area. Conversely, sensory impulses from the skeletal muscles and
other somatic structures initiate changes in the impulses governing the
functions of the visceral muscles and glands, as well as the reflex actions
usually recognized. This relation of the somato-visceral and the
viscero-somatic reflexes underlies all the physiology of the osteopathic
Structural Nerve Relations.
anatomy of the nervous structures concerned in these reflexes is fairly
well known. The axons of the sensory ganglia enter the spinal cord
as its posterior roots. After the Y-division both branches of the
axon give off collaterals which penetrate the gray matter and form synapses
with the neurons of the anterior, lateral and posterior horns, and of Clarke’s
column. According to Barker, probably every axon sends collaterals
to every region of the same, and probably also to every region of adjoining
spinal segments. Thus the structure of the neurons is such as to
facilitate the occurrence of both somato-visceral and viscero-somatic reflexes
through every segment of the cord. (Note A.)
ordinary somatic segmental reflex actions are effected by impulses carried
over the somato-sensory neurons either directly or by means of interpolated
association neurons to the somato-motor cells of the anterior horns of
the cord. The axons of these terinate upon the skeletal muscles.
ordinary segmental visceral reflex actions are effected by impulses carried
by the viscero-sensory neurons either directly or by means of interpolated
association neurons to the viscero-motor cells of the lateral horns of
the cord. The axons of these cells terminate by forming synapses
with the sympathetic neurons, and the axons of the sympathetic neurons
terminate upon the visceral and vascular muscles, the glands, etc.
The cells of the lateral horns send their axons outward chiefly with the
anterior roots. It is these fibers which make up most of the white
rami communicantes, the splanchnic nerves and the erigentes. The
visceral portion of the third cranial nerve, the vagus and those parts
of other cranial nerves which are concerned in visceral activity arise
from groups of nerve cells which are homologous with the lateral horn neurons,
and, like the splanchnics, terminate around the cells of the peripheral
sympathetic ganglia. According to Howell, there is probably only
one relay between the viscero-motor center in the spinal cord or sub-cerebral
centers, and the destination of the nerve impulse.
viscero-somatic reflexes are effected by means of impulses carried by the
viscero-sensory neurons either directly or by means of interpolated association
neurons to the somato-motor neurons of the anterior horn, thence to the
somato-visceral reflexes are effected by means of impulses carried by the
somato-sensory neurons either directly or by means of interpolated association
neurons to the lateral horns of the cord, thence to the sympathetic ganglia,
and thence to the viscera.
structural relationships are seen in slides from the various regions of
the cord, medulla, pons, and mid-brain. The functional relationships
indicated by these structures have been demonstrated by experiments upon
animals and persons, as well as by observations upon sick people.
Superficial Centers in Diagnosis.
superficial centers are of value in diagnosis, because the disorder of
any visceral structure initiates a reflex muscular tension in the superficial
center of that organ. Both the visceral disorder and the abnormal
muscular tension produced by it are a source of increased nerve impulses
to that segment of the cord This abnormal increase of nerve stimulation
lowers the threshold of the neurons concerned. Thereafter the receipt
of normal impulses initiates extravagant reactions, both in consciousness
and reflexly, because of the lowering of the neuron threshold. For
this reason, the existence of marked muscular tension and of areas of increased
sensitiveness along the origin of the nerves to any viscus is evidence
of some abnormality of the structure or the function of that viscus.
Superficial Centers in Therapeutics.
therapeutics, the same principle is concerned. Since the visceral
activity may be affected by sensory impulses reaching the segment of the
cord from which it is innervated, then it is evident that abnormal impulses
from abnormal conditions of skin, muscle, articular surfaces, or other
structures may exert an abnormal influence upon the visceral activities.
This being true in any given instance, it follows that the removal of the
cause of the abnormal sensory impulses, or the removal of that which interferes
with the normal flow of sensory impulses, must exert a favorable effect
upon the progress of the patient toward a normal condition, unless permanent
structural changes have been caused by the persistence of the lesion.
therapeutic procedures are indicated by the diagnosis and the etiology.
Whether complete recovery will result from the removal of the original
cause of the disease or not depends, it is evident, upon the nature and
extent of the secondary changes which have been produced. In cases
of structural mal-adjustment of long standing, certain changes occur in
the gross structures, and also in the habits of metabolism of the cells
which have been subjected to abnormal conditions of innervation.
Absolute recovery, then, must be slow and uncertain. The symptoms
may often be greatly relieved, in these cases, even when absolute recovery
cases of acute illness, due to indiscretion, or to temporarily abnormal
conditions of the environment, not associated with gross structural changes,
it is sometimes possible to relieve the most annoying symptoms by manipulation
of the center controlling the disturbed function. This is merely
a palliative measure, but it is a very effective one whenever it is indicated
by the condition of the patient. The efficiency of these measures
depends upon the integrity of the neuron systems by means of which the
reflex actions are effected.
Note A.—(Figure 1)—“The outlines of the
cord and of the gray matter in it, and of the sensory and sympathetic ganglia,
are drawn to scale. The size of the nerve cells is magnified and
their arrangement is diagrammatic. It would be impossible to secure
in a single slide all of these relationships.
“The fiber “A” is viscero-sensory. The body of the cell is in the
sensory ganglion ‘H.’ The peripheral prolongation, properly called
a dendrite, is medullated. It passes through the sympathetic ganglion
‘F,’ without making any physiological connection with the sympathetic neurons,
so far as known, and is distributed with the sympathetic nerves.
These fibers retain their medullary sheaths until they reach the neighborhood
of their termination in the viscera. ‘B’ is a viscero-motor fiber,
the axon of a cell in the lateral horn ‘O’ of the spinal cord. These
fibers form the greater part of the white rami communicantes, and they
usually pass through one or more ganglia before forming a synapsis with
sympathetic neurons. These fibers are medullated until they reach
the ganglion of their termination. ‘C’ is a viscero-motor fiber,
the axon of a cell in the sympathetic ganglion ‘F.’ These fibers
are not medullated, usually, and the medullary sheath is extremely thin
in the very few instances where it is found at all. Impulses carried
over these fibers are derived from the lateral horn. “The lateral
horn of the spinal cord ‘O’ should be considered as part of the autonomic
nervous system, of which the sympathetic nerves also are a part.
The nerve cells of the lateral horn of the cord are smaller than those
of the anterior horn, and the axons of these cells are finer. The
axons terminate by forming synapses with sympathetic neurons. The
cells of the lateral horn of the cord receive impulses from several sources,
-- from cells in the posterior horn ‘K,’ from cells of the spinal ganglion
‘H,’ by collaterals from their axons ‘L,’ from the red nucleus by way of
the rubro-spinal tract ‘X,’ from the vasomotor and other centers in the
medulla, and perhaps from other sources. Impulses are carried to
the lateral horn only from sensory nerves and from centers which
coordinate sensory impulses.
all the sensory nerves entering the cord send collaterals to the lateral
horn of the same spinal segment. Normally, the sensory impulses carried
to the cells of the lateral horn are just sufficient to initiate the viscero-motor
impulses necessary to the normal action of the visceral and vascular muscles
and the glands of the body. If these impulses are deficient,--as,
for example, if the threshold values of the neurons concerned should be
abnormally high,--the outgoing impulses are deficient. Any abnormal
stimulation of the sensory nerves initiates abnormal stimulation of the
cells in the lateral horn, and through these, of the sympathetic nerves.
This abnormal stimulation may be received through viscero-sensory nerves
as is the case in the presence of indigestible food, etc., or it may be
derived from abnormally contracted muscles, from joint structures held
in abnormal tension, as in subluxations, or, rarely, from the skin itself.
collaterals from the sensory axons pass also to cells of the anterior horn,
abnormal viscero-sensory impulses may initiate the abnormal contraction
of the spinal muscles. This tension may in time bring about mal-position
of the vertebrae. Both the muscular tension and the mal-position
may in turn initiate abnormal sensory impulses which stimulate the cells
of the lateral horn in an abnormal manner. This reflex muscular tension
and the exaggeration of the viscero-motor impulses thus produced are of
great value to the body under slightly abnormal conditions, but are a source
of great misery if the visceral abnormality be continued. The effects
produced from this long-continued muscular tension are probably not to
be distinguished from those resulting from accidental structural mal-adjustments
of long standing.” -- From “How Osteopathic Lesions Affect Eye Tissues,”
The Journal of The American Osteopathic Association, March, 1907.
Sensory Visceral Areas, in Morat’s “Physiology of the Nervous System,”
p. 154, Edition of 1906.
Chapter XXVII, in “The Nervous System,” by L. F. Barker.