Studies in the Osteopathic
Basic Principles: Volume
Louisa Burns, M.S., D.O., D.Sc.O.
EXTERNAL CHANGES AFFECT ABNORMAL RATHER THAN NORMAL TISSUES.
long been accepted as an axiom that “a bad cold always settles in the weakest
place,” and that “fever always goes where there is sickness already.”
There are other sayings which have the same significance. Not all
old sayings have a basis of truth; some of them have their only foundation
in some tradition of witchcraft, yet others, such as these just mentioned,
have a true principle underlying them.
that we are able to do for the relief of suffering would be of no value
if normal tissues were affected equally with the abnormal. As a matter
of clinical experience, we do affect the abnormal tissues without subjecting
the normal to any interference with their activities. It is the function
of this chapter to offer some explanation of the facts as noted.
Variations in Metabolism.
the first place, the metabolism of the cells which are being subjected
to abnormal influences is more or less variable in character. If
any organism is placed under circumstances of unusual stress the series
of chemical changes which make up its life history becomes very changeable
in nature; the waste products of metabolism are not quite those characteristic
of the same organism in health; the food stuffs taken up from its environment
are not just the same as those used under normal conditions, and the whole
quality of the metabolism becomes changed in the effort to adapt itself
to the abnormal environment. In case of an organ of the body which
is being affected by adverse influences, not only are the facts just mentioned
true, but the function of the organ in the bodily economy varies in greater
or less degree from that it serves in health. This erratic condition
of the metabolism of the cells laboring under abnormal conditions renders
them more subject to further disturbance from changes in the environment
of the body than are the cells whose metabolism is a fairly stable result
of an inheritance of some generations of practically unchanged surroundings.
factor in this relationship is found in the quality of the walls of the
blood vessels. These are somewhat elastic, besides being muscular,
and are therefore subject to distension and relaxation as the result of
changes in the blood pressure and in the action of the vaso-motor nerves.
When the walls of any given group of blood vessels are relaxed, if the
general blood pressure remains high, the capillary endothelium is subjected
to a considerable strain. The formation of the nutrient lymph is
thereby promoted to a certain variable degree. If the dilatation
be increased to an abnormal degree, the phenomena of inflammation ensue.
If the area affected include any of the mucus membranes of the body, the
goblet cells increase in function, and, if the abnormal conditions persist,
they increase in numbers also. If the dilatation is soon relieved,
no permanent ill effects of the disorder are afterward recognizable.
But if the dilatation should continue for a sufficient time, the muscles
of the arterioles react to the strain, as both striated and non-striated
muscles usually do, by becoming longer. This condition of the vessel
wall is comparable to the condition of the gastric musculature in dilatation
of the stomach.
results, then, in a dilatation of the blood vessels which is more or less
permanent, according to the length of time during which the dilatation
persists, the pressure to which the injured vessels were subjected, and
the powers of recovery of the patient. This last factor is of no
especial interest in this discussion. Now the tissues whose vessels
have been dilated in some such a manner as that just described, must perform
their work with a certain amount of difficulty; it may be that no abnormal
symptoms result, because the organs of the body are able to perform their
functions fairly well under considerable degrees of embarrassment; but
if the handicap be too great, or if other injurious factors be active,
the failure or malfunction of the tissues involved is apt to become very
evident. It will be conceded that the organ whose vessels are even
slightly permanently dilated is not to be considered a normal organ.
These vessels are more subject to further dilatation than are normal vessels.
Therefore, any sudden contraction of the vessels supplying another part
of the body, or any sudden increase in the force of the heart’s beat, exerts
an ill effect upon them rather than upon the normal vessels. The
tissues in the area of distribution of the affected vessels then suffer
slight permanent dilatation of the arterioles is present in the mucus membranes
in the condition ordinarily called “catarrh.” For a bad cold to “settle”
in any part of the body is for the arterioles already somewhat weakened
to become greatly dilated by a sudden rise in blood pressure. The
effect of such dilatation is to induce the phenomena of inflammation, if
these be not already present, or to increase them of they were already
present. Every such additional dilatation weakens the vessels and
renders recovery more difficult.
factor concerned in the comparative ease with which abnormal tissues are
affected by external changes lies in the physiology of the nerve centers
controlling the diseased organ. The metabolism of every organ or
cell group in the body is regulated by a continual stream of nerve impulses
passing from the central nervous system. Sensory impulses from any
organ assist in the determination of the motor and secretory and vaso-motor
impulses to that organ, and others related with it in structure or in function.
“All structures innervated from the same segment of the spinal cord are
affected by sensory impulses reaching that segment,” Any diseased
or injured organ sends a continual stream of unusual sensory impulses into
the central nervous system; these may be sent into consciousness as sensations
of pain or discomfort, or they may simply initiate reflex changes in the
size of the vessels or in the activity of the diseased organs, of the other
structures innervated from the same segment of the cord or from the same
sub-cerebral area, or other tissues in relation with it.
The Neuron Threshold.
repeated stimulation of any neuron or neuron system lowers its liminal
value. The more frequently nerve impulses reach any nerve center
the more easily it is stimulated, and the quicker and the more pronounced
is its response to stimulation. The continual irritation of the nerve,
centers by the sensory impulses initiated from the abnormal structure or
the abnormal metabolism of any organ lowers the neuron threshold or liminal
value of these centers and renders them more easily affected by any stimulation
than are the same centers under normal conditions.
is evident, then, that if any series of impulses reach a certain segment
of the cord, or any group of neurons, the structural relations being equal,
the effect of this stimulation will be chiefly manifested by those neurons
whose liminal value is lowest. So, if any center has been receiving
an abnormal number of sensory impulses, as is usually the case with centers
in relation with diseased organs, it is very greatly affected by comparatively
slight stimulation. This effect is most apparent in those reflex
actions which are of a segmental nature, or are apparently so.
Example of Segmental Reaction.
any structure innervated from a given segment of the cord be diseased,
the neurons which control that segment have a lower liminal value than
other neurons of the same segment. This relation is of fundamental
importance in determining the effects of certain therapeutic methods.
example, that segment of the cord which gives origin to the eighth thoracic
nerve sends fibers from its lateral horn which carry impulses to the sympathetic
neurons which influence the size of the blood vessels in the stomach and
pancreas, and affect the secretions of the gastric and pancreatic glands.
This same segment of the cord also sends fibers from its anterior horn
which terminate upon the striated inter-costal muscles. This segment
of the cord coordinates the activity of other structures, not concerned
in this illustration. If the articular surfaces of the eighth dorsal
vertebra be irritated in any manner, sensory impulses will be sent into
the cord and cephalad, and also reflex impulses will be sent out over the
efferent paths which will affect either the stomach, the pancreas, or the
intercostal muscles, according to the comparative liminal value of the
neurons governing these structures. If the stomach be laboring with
a mass of indigestible food, at the time of the irritation, the liminal
value of the neuron system whose duty it is to coordinate the impulses
concerned in gastric activity will probably be lower than the liminal value
of the other neuron systems of the same segment. The stomach will
then be more quickly and more urgently affected by the abnormal irritation
than the other structures. The principle holds true for every segment
of the cord and for every center in the medulla, pons and mid-brain, so
far as their physiology in this respect has been investigated.
Effects of Fatigue.
principle in its application to the nerve centers hold true only so long
as the neurons concerned are active. After a certain time, which
varies according to a large number of factors, the neurons whose liminal
value has been abnormally lowered become fatigued. At first, the
effect of fatigue is to lower the liminal value in still greater degree,
so that the stimuli almost negligible under normal conditions may at this
time initiate excessive reactions. Afterwards, progressive degrees
of fatigue and exhaustion lessen the power of the neuron to respond to
stimulation until it becomes almost, if not quite, inert and functionless.
During this period of decreased function on the part of the neurons innervating
the diseased organs, its metabolism is affected less and less by external
changes, and its own abnormality exerts less and less of an effect upon
the other tissues of the body, by means of the nervous system. After
this time, no compensatory action is possible through the intermediation
of the central nervous system, and, on the other hand, no injury is offered
the other organs of the body by means of the central nervous system.
This loss of the nerve reactions may serve a useful purpose in many instances.
It forces a rest of the abnormal organ which may facilitate recovery; it
may prevent the injury of other organs, and it may save the patient from
useless suffering during the last of his days.
for the lack of the functions of the diseased organ may be secured otherwise
than by means of reflex action. This compensation is always something
of a patch work affair, though it is much better than no adaptation at
methods owe much of their efficiency to the principle at the head of this
chapter. If it be desired to increase the efficiency of the muscles
of the dilated stomach, for example, it is possible to stimulate the tissues
near the eighth dorsal spine and thus to initiate nerve impulses which
will affect the stomach, or the spinal or inter-costal muscles.
for the development of a scientific and exact system of healing, but fortunately
for the patients, this principle is a boon to the ignorant and careless
practitioner, whether he be of never so rational school. While the
chances are about even as to whether he will help his patient or will injure
him, he is not very apt to affect the normal tissues seriously unless he
brings about some very severe structural changes. The apparent cures
that frequently follow unintelligent manipulations are to be explained
upon the basis of this principle. On the other hand, the very fact
that abnormal tissues are more easily affected than normal readers the
injury produced by unwise manipulations of the osteopathic centers in relation
with the diseased organ decidedly disastrous, under certain circumstances.
fact that the abnormal rather than the normal tissues innervated from the
same segment of the cord are most affected by sensory impulses reaching
that segment renders it possible for the skilled physician to affect almost
any diseased organ in almost any manner he chooses, so long as the nerve
centers are not exhausted. After this, he may secure the same end
by indirect means, employing changes in general blood pressure, the activity
of other organs, volitional impulses and other factors in securing either
recovery, adaptation, or compensation.
A.—A familiar instance is found in an aching tooth. Every jar or unpleasant
sensation increases the pain in the tooth. If one with toothache steps
on a tack, the ache may be increased thereby. And every one knows how
much longer the aching tooth is than its fellows.