the same axial line. Each segment contains in association which is
morphologic, physiologic, and anatomical, a segment of nerve matter and
a somatic (body) segment. The neural segments are arranged end to end
so as to form the rudimentary beginning of the complete central nerve
axis of the adult human body; the somatic segments blend together with
somewhat indefinite lines of cleavage which are to become much more
indefinite and obscure by changes in relative form due to differences
in the growth rate of different parts or to involuntionary changes
following functional inutility at various periods. Gray says, “The
intrinsically segmental nature of the spinal cord is expressed by the
association of each definite segment with the somatic segment supplied
by its nerve.”
Within each segment there may be observed at an early period cell
migrations from the walls of the primitive neural tube and amoeboid
projection of axonic and dendritic processes from these cells, which
serve to bring the other tissues of the segment under the control of
the nerve elements; there is an assumption of command, as it were, by
the nervous system, so that the epithelial, connective, and muscular
tissues of each segment are linked in sensomotor and vegetative
co-ordination by the contact association of the nerves which ramify
them--sensomotor because the nerves are presently to carry the only
force capable of inciting activity of any kind in other tissues,
vegetative because the functions of growth, nutrition, and repair, in
each somatic cell, depend upon the continuity of communication between
it and the lowest nerve cell in the nerve pathway which connects it
with the higher motor and sensor centers.
Development of the Nerve System
Already may be noted a hint and a prophecy of that future segmental
organization by which it becomes possible for some spinal vertebra to
become displaced and thus begin a morbid process which may diffuse
itself throughout an entire body segment, involving neural and somatic
elements together. Already the simple organization begins to become
rapidly complex and difficult to trace.
Cell masses begin to migrate from the walls of the primitive neural
tube to a position laterad to become the spinal ganglia; these send
out long dendritic processes which marvellously thread their way to a
predetermined peripheral connection which is to bring some cutaneous,
or muscular, or joint tissue into sensor relation with the dorsal,
or Sensor, portion of the cord and through it with the brain; at the
same time they send their axonic processes inward to mingle with and
communicate with the dendrites of other sensor cells remaining in the
central axis to form the gray matter of the cord, and thus, migrating,
keep up communication both with the central axis and the periphery.
Other cell masses migrate ventrolaterad to form the sympathetic ganglia
and they also send out afferent and efferent processes which make a
connection on the one hand with the periphery and on the other with the
source from which the cells developed, the situation to be occupied
by the cord. From this view it is seen that the sympathetic system
is merely an offshoot from the same source with all the rest of the
peripheral nerve system, merely a mechanism for the proper distribution
of nerve impulses from the central organs, and that it retains its
connection in all its parts with those organs. Its ganglia, like those
of the cord, are always and from the beginning under the domination of
the upper or cephalic end of the neural tube.
This cephalic end rapidly expands. Its growth is faster than the rest
of the neural tube and from its walls, by proliferation, develop the
structures of the cerebrum, mid-brain, and hind-brain. It also gives
off ganglionic masses from which grow sensor processes to form the
afferent elements of the cranial nerves and contains, like the cord,
motor nuclei, or nidi, from which motor axons grow toward the periphery
to come into relation with definitely predetermined organs.
The Spinal Column and Cranium
Now appear the primitive cartilaginous and membranous elements from
which a bony wall is to be built around the central nerve axis,
primitive vertebrae, the upper known as cranial and numbering four,
and the lower, or spinal, numbering usually thirty-three. These bone
structures develop around the brain and spinal cord. Later the cephalic
vertebrae fuse into a solid vault, the cranium, completely enclosed
except for various foramina for the passage of spinal cord, nerves, and
blood-vessels. The succeeding twenty-four vertebrae remain separate and
movable upon each other and leave between them the openings for the
emergence of the spinal nerves. The last nine segments fuse eventually
into two immovable or false vertebrae called Sacrum and Coccyx. These
latter also contain foramina from which nerves issue.
The Adult Nerve System
When this development and growth of new parts is completed the
Nerve System appears as a set of complex organs made of a central
axis, brain and spinal cord, and peripheral connections made up of
forty-three pairs of directly attached nerves (12 cranial and 31
spinal) with two great gangliated cords and numerous other sympathetic
ganglia and communicating cords situated outside the skeletal axis
but communicating with it intimately by means of interchange of fibre
bundles between the sympathetic and the cerebro-spinal nerves.
[Illustration: Schematic diagram of Spinal nerve and Rami.
A: Spinal nerve. B: Spinal ganglion. C: Posterior nerve root. D:
Anterior nerve root. E: White ramus communicans. F: Gray ramus
communicans. G: Sympathetic ganglion. H: Sympathetic cord.
After Gray
Parker
31. Interchange of fibre bundles between spinal and sympathetic
nerves.]
But we who have viewed the embryonic development even briefly and
sketchily, understand that all these complex organs are merely an
aggregation of neurons, each neuron made up of a cell body, one or more
axons, and dendrites; that the nerve cells are the controlling elements
and the axons the centrifugal carriers of nerve energy, while the
dendrites are the centripetal processes through which each nerve cell
receives communications.
The Body Axis
The skull and spinal column, taken together, constitute the bony axis
of the body, the center of organization of the skeleton; to these parts
are attached other skeletal structures, mandible, ribs and sternum,
extremities, classified as the appendicular portion of the skeleton.
Likewise are attached, directly or indirectly, the voluntary muscles
which move the skeleton, and the vessels and viscera. Any given
structure in the body can be traced to a supporting connection with
this bony axis.
The bony axis contains the neural axis. Its strength and solidity are
such as to preserve the integrity of the most vitally important tissue
of the body from every form of injury if such protection be possible.
Through openings in the bony axis--foramina--the central nerve
organs give off or receive the nerve bundles which bring them into
communication with every other structure of the body. And the body has
been so arranged that every single part of it is partly or wholly under
control of nerves emerging through these foramina. Even the brain
and spinal cord themselves respond to changes in the blood-vessels
which are controlled by nerve impulses which have emerged through the
intervertebral or cranial foramina and returned by other routes to
supply the muscular coats of the vessels.
Concussion of Forces Affects Spinal Column
Reverting for a moment to the primitive segmental arrangement which
is none the less persistent and important because in the completed
human the regularity of contour of the segments has been wholly lost
and aberrant organs have moved from their original positions carrying
their nerve supply with them, let us first state and then illustrate a
general law.
Any violence applied to the body tends to affect the spinal column.
Such violence does or does not produce permanent displacement of a
spinal segment according as it does or does not succeed in overcoming
the internal resistance. But whatever effect upon the spine is
accomplished will occur most noticeably in the same body segment
to which violence was applied. That is, force applied to any body
segment tends to subluxate the vertebra which would impinge the nerves
controlling that segment. Thus diseases are primarily segmental and
later general just as the body is primarily segmental and later
co-ordinated into complicated functional systems, all more or less
interdependent.
If a man falls so that he strikes first on the point of his shoulder
the force will be transmitted almost directly across the line of the
spine, at right angles, and may subluxate the sixth or seventh Cervical
or first Dorsal. If subluxation occurs it is because the law of gravity
causes the remainder of the body to keep moving downward after the
shoulder strikes and until it too comes to rest. The subluxation
which results is a right one if the left shoulder be struck and vice
versa. Now the brachial plexus is chiefly controlled by these three
vertebrae and a right subluxation tends to impinge most the nerves
on the left side, so that if any permanent effect of the fall follow
it will be a permanent weakness or disease of the left shoulder or
arm, with possible slight extensions along other branches of the same
plexus, as to the latissimus dorsi. Also by the internal sympathetic
communications from this same region the larynx, trachea, or large
bronchi may be affected, occasionally the heart, all structures
segmentally associated with the arm.
This law applies throughout the body and can be fully demonstrated
by any one having a complete knowledge of nerve connections and body
segmentation upon being furnished with a complete and accurate history
of any injury to the body. It goes further than this. Toxins or other
secondary causes operating within the body tend always to produce their
motor reactions and consequent effect upon any subluxated vertebrae in
the same body segment with the peripheral irritation, so that if the
stomach contain a poison which affects the spine the sixth or seventh
Dorsal vertebrae will be most affected and the stomach itself the organ
to suffer most.
The spinal column is peculiarly adapted, with its strong ligaments,
its cartilage cushions, its perfect flexibility and flexuousness,
to withstand jars and shocks. Yet the spine is the door by which
disease enters the organism. Concussion of forces, the energy from the
environment encountering the bodily resistance, is of no serious effect
upon the organism--of no permanent or irreparable effect--unless it
affects the spine and brings about vertebral subluxation, disturbance
of the normal alignment between vertebrae, and thereby interrupts the
perfect healing and controlling influence exerted by the vital part of
the segment, the central nerve portion.
When a concussion of forces _does_ produce subluxations, does disturb
the perfect poise and balance of that center of structure of the body,
its consequences affect an entire body segment, producing, or tending
to produce, disturbances through the entire segment.
Disease is the indirect consequence of the contact of man with his
environment and is _natural_ but not _normal_.
The spinal column is a _center_ or a series of centers for disease.
In this column will be found the primary cause--the introductory
element--by which disease first makes its appearance in a previously
healthy body.
Comparative Anatomy
The study of Comparative Anatomy is necessary to a complete
understanding of the human organism. We may trace in the simplest forms
of animal life the beginnings and foreshadowings of the same plan of
organization. We may follow it through the ascending scale and watch
its complexity develop, and by viewing each step in the process we
may come fully to realize that the original plan has been preserved
throughout, though often in such form that by study of the single
species we should fail to recognize it.
We lack space for complete consideration of this subject and shall
merely suggest certain facts and phases. No clear analogy can be drawn
until we reach the worm, with its rudimentary spinal column and nerves.
Roughly speaking, dissection of one spinal segment with its nerves and
their controlled area--if this were possible--would separate from the
rest a fairly regular _layer_ similar to all the other layers. This is
the primitive segmentation.
It is shown much more clearly in the fish but the segments have begun
to curve with their periphery directed slightly caudad and some have
already shown a preponderating growth over other segments and a change
of shape from the original symmetry.
The reptiles and birds show still more complicated segmentation. It
is notable that in these lower animals the purely reflex portion
of the nervous system is highly developed while the volitional and
sensory portions, the cerebral hemispheres, are yet rudimentary. In
birds, particularly, the cerebellum is very highly developed because
its function of co-ordination of muscles for the maintainence of
equilibrium is required in a high degree for flying.
Those land animals which walk on all fours approach still closer
but their arrangement is much more readily comprehensible than in
man. As the animal stands on all fours with head extended, a gigantic
cleaver slicing out each vertebra and pair of nerves and slicing
straight toward the base of support might be said to divide the body
_approximately_ according to the structural and functional arrangement
in segments. Yet no segment so separated would exactly correspond to
the nerve distribution; there would be enlargement of some organs
with extension into the zone previously occupied by their neighbors;
enlargement here and atrophy there; invagination of one organ by
another and overlapping and intermingling of parts. Even the relation
between the spinal cord segments and the vertebrae has departed much
from the primitive so that the growth of the vertebrae has exceeded
that of the cord and the cord terminates opposite the Lumbar region
instead of at the end of the Sacral canal. It may here be remarked
that in the human embryo the cord at first occupies the entire length
of the neural canal formed within the vertebrae; that in the adult it
terminates opposite the lower border of the body of the first Lumbar
vertebra and that the nerves, still retaining their original foramina
of exit and their relation to the somatic segments, pass downward
within the canal to their respective openings and collectively form a
brush like mass called “cauda equina.”
Causes of Segmental Changes
The causes of the change in the shape, form, and relation of the
different segments are functional: the body changes to meet the
changing needs of its environment and the steady progressive functional
development from one species to another.
When the animal at last assumes the erect position, doing more
intricately and intelligently the bidding of a developing and improving
central nervous system, the change of position and the force of gravity
bring about a gradual downward, or caudad, tendency of the parts of the
somatic segments most remote from the spine and of the nerves which
supply them.
The nerves, muscles, and bones of the lower extremities change from
almost a right angle to an extremely obtuse angle, less obtuse during
infancy and more so in the adult. The forelegs become arms and hang at
the sides, extending downward from the part of the spine which controls
them. The ribs tend more obliquely downward and outward from the spine
and the tendency of all the nerves is downward from their attachment to
the spinal cord to their emergence from the intervertebral foramina. In
the neck and head alone is this rule varied, the tendency of the nerves
and some other structures there being to run from the spine either at
right angles or upward.
It seems almost symbolic and indicative of the purpose of creation that
the body, which is less strong and vigorous in Man than in the lower
animals, should tend more and more obliquely downward from its central
axis, while the cranium, containing a highly specialized mass of cells
and fibres, the organ of Mind, which marks Man’s supremacy in the
animal kingdom and is his crowning glory, is reared _above_ the body it
dominates.
In all the form changes which mark the growth of the body the organs
are arranged to afford the greatest possible economy of space and
convenience for use. This perfect and matchless mechanism adapts itself
to the changing habits and environments and to the quality and needs of
the Mind which inhabits it.
Necessity for Table of Spino-Organic Connection
To the practitioner who is fully equipped with an instantly available
knowledge of all the nerve connections in the body and to whom
palpation of a subluxation at once suggests its somatic sphere of
influence as a weakened or diseased area, or to whom mention of a
disease immediately calls to mind the organ, or segment, which is
primarily affected and its nerve connection with the spine, any
tabulation of spino-organic connection or of diseases and adjustments,
for reference, is unnecessary. But the ordinary practitioner finds it
difficult to acquire and retain such an array of information and much
more convenient to refer to reliable and easily read tables which will
supply at once any such information desired.
No specific adjustment is possible without knowledge of the vertebra
which controls the part diseased and toward the healing of which the
nerve energy should be directed. Specific adjustment without correct
diagnosis is of course impossible. And whenever correct diagnosis has
been made it is essential that the mind of the Chiropractor should
revert to one certain vertebra which he expects to find subluxated as
the primary cause of the disease.
Diagnosis is essential in order to find out _what_ organ is the site
of the disease, for all disease is primarily segmental. The _location_
of the disease having been determined, a quick reference to a table
showing the spinal connection with that location makes specific
adjustment possible. The value of specific, as against general,
adjustments will be considered under “Practice.”
Method of Investigation
One who wishes to determine for himself the proper specific adjustment
for a certain disease must, in order to be able to attach any weight to
his conclusions or to announce them with any hope of credence by the
scientific world, proceed very much after the following method, which
sets down what may be termed “standard test conditions” for research
into the spino-organic connection.
He must make a correct diagnosis which serves to determine the nature
and location of the disease process. In this he may be greatly aided
by vertebral palpation and nerve-tracing, especially in differential
diagnosis. Any case which affords less than a quite positively correct
diagnosis should be excluded from the test list because any conclusion
based on a doubtful diagnosis must itself be doubtful and may be
seriously misleading.
He must then ascertain as far as possible the known anatomical nerve
connection between the spine and the diseased part. If several
connections are known he must decide according to nervous physiology,
by recognizing the morbid functions which constitute the disease and
learning which nerves control these functions and which must therefore
be deranged in order that the disease may exist. I may say right
here that to attempt to answer the problems of Chiropractic on the
assumption that standard anatomies are incorrect in their statement of
nerve connections is as hopeless as the wail of the schoolboy that the
answers in his arithmetic are wrong because his sums fail to come out
that way.
The investigator must next be accurate in Palpation, selecting the
subluxation which would, from his knowledge of the body segmentation,
seem most likely to influence the nerves involved, and positively
ascertaining the _number_ of the subluxated vertebra. No one who cannot
count vertebrae accurately can positively say which vertebra he has
adjusted. More than that, no one who _has not_ counted the vertebrae in
the special case in question can say which vertebra he has adjusted. No
mere regional localization will suffice for scientific investigation.
Correct and accurate adjustment must follow selection of the single
vertebra and the adjuster must know that he has used the one
special movement, or form of adjustment, which is mechanically right
for that kind of subluxation and has so moved the vertebra as to
release impingement. Mere movement of a vertebra is not necessarily
an adjustment or even a maladjustment; it may be movement without
permanent change of relation or release of impingement. (See
“Preferable Adjustments,” p. 155.)
There follows the observation of the progress of the case and this
must be so careful and accurate that the observer knows to a certainty
whether the disease is progressing unfavorably, or favorably, or
whether it has been entirely eradicated. He must know the value of
every changing symptom, the real meaning of each new development. Every
diagnostic method should be at his command for this work. Constant
vigilance and constant thought should mark each step of his work.
Finally he must be so cautious and careful in his statements that no
doubtful conclusion is allowed to escape from his own mind. We may
believe or suspect or hope for proof of our theories but we have no
right to state as a fact anything except that which has been proven
under the most rigidly guarded scientific test conditions.
Failure to observe any of the precautions mentioned renders worthless
the results of investigation. Nothing further than a mere presumption
can be based upon research which fails to observe all these rules.
It will be readily understood that there are few Chiropractors
whose training has been sufficient to enable them successfully to
accomplish such research. There are thus many things connected with the
spino-organic connections which are commonly held as facts but which
should be classed as presumptions. And the prevalence of the habit of
general adjustment rather than specific makes the future final solution
of all these problems remote.
Kinds of Evidence Acceptable
It will be seen that of the three kinds of evidence--Anatomical,
Physiological, and Clinical--which are admissible in reasoning upon
the connection between the spine and disease, only one form--clinical
evidence--has been adduced by Chiropractic. For anatomical and
physiological corroboration of our apparent clinical findings we are
obliged to turn to standard works on these subjects; fortunately we
find it in abundance.
Anatomy, fortified now by research in the morphologic relations of the
parts studied and by physiological and pathological experiment which
has thrown much light on the proper viewpoints from which to describe
structure, contains sufficient data on the nervous system to enable us
to explain practically every fact observable in a Chiropractic clinic.
It is true that there are a few statements in the ensuing outlines for
which we cannot as yet find the anatomical or physiological proof. But
it must be remembered that anatomists and physiologists have never
studied the body with a knowledge of the subluxation theory to aid them
in gaining perspective and that Chiropractors, as a class, have not
yet delved deeply enough into anatomy and physiology to extract all the
available and illuminating information from them. Ofttimes the facts we
value most are most obscure in the texts because to others they seem
least important. But they are there. Armed with information concerning
Chiropractic facts it is probable that the scientist of the future will
corroborate all of our clinical findings of today and emphasize the
rational explanations of them.