Part 40

But merely to state that a second Dorsal subluxation causes heart disease is not enough. We must know why and how it causes heart disease and whether, perchance, some other subluxation may sometimes have a like effect. We must map out the sphere of malign influence of each possible subluxation so that when our fingers encounter it it at once and inevitably suggests its possible effects, from which, by diagnostic methods, we may choose the one toward which most symptoms point. And we must know the relation of every nerve in the body to peripheral organs and their functions so that when we encounter indubitable evidence of some functional or organic disease we may know exactly where, in the spinal column, to seek for its cause.

We have learned how to discover a subluxation, how to adjust it, and how that adjustment permits a natural cure of its abnormal effects. We must now learn exactly where to apply adjustment for any given organ in the body or for any disease. It must be understood in interpreting this statement and all those which follow in this section that it is never proper to adjust a vertebra merely because it is stated to be the cause of a disease believed to exist in a patient. No vertebra should be moved unless palpation determines it to be subluxated. Rather let it be known that as a rule the statements of spino-organic connection here made will prove to be verifiable by palpation. There is no rule in Chiropractic without some exceptions, and mere diagnosis of disease is too notoriously unreliable to serve as a guide to adjustment without the verification of the trained touch.

The Field of Study

We wish to know the relation existing between each part of the Nerve System and other parts and between each part and the other organs of the body. Especially we wish to understand the relation between each part of the Nerve System and the spinal column, by which permanent subluxations of the latter interfere with the former’s action and therefore with the peripheral organs.

This requires a general knowledge of anatomy, physiology, and pathology which we shall presuppose the reader to possesses so that we may present only facts to which his attention should be particularly called. Let us begin with the relation of nerve tissue to other tissues where this relation can be most clearly comprehended, namely, with the development of the human embryo.

Segmentation

The complete human organism represents the snarled fusion of a series of similar, yet specialized, somatic segments, each presenting most of the attributes of a simple animal, though the association and co-ordination of all are required for the production of higher animal phenomena.

The embryo is composed of such segments placed with their centers in 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.

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.