It has been said in a previous section that when subluxation and disease are associated the subluxation always precedes the disease and that the former is the cause, the latter the effect. So clearly do we understand this law that we are able to say what subluxation would cause a certain disease and err by only so many cases per centum as there are variations from the usual structure of the spinal column and the nervous system.

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.

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.

In the following tables it has been found best to insert in parentheses the capital letter (P) to call attention to any statement in support of which we have gathered less than all three forms of admissible evidence and which is therefore as yet presumptive. It is well, however, for the practitioner to be careful lest he regard too lightly such presumptive statements. Unless there is very strong and reasonable ground for such presumption or a general belief in its correctness all mention of it is omitted. Those labelled presumptive are merely so indicated because they have not yet been proven and not because they have failed to serve as a convenient and useful guide to adjustment. For each presumption offered there is either clinical or anatomical justification but not both.

SPECIAL NERVE CONNECTIONS

This section does not purport to state with any degree of completeness the various nerve-paths by which spinal vertebrae come into relation with all, or nearly all, the peripheral organs of the body. It merely points out some of the more interesting and important connections, some of the paths which serve to explain the common effects of vertebral adjustment. It is not expected that this resume of the subject will be more than suggestive to the student; certainly it cannot, in so brief a space, be a complete exposition.

Outline of Nerve System

Let us begin with the observation that almost every organ of the body, including the central nerve organs themselves, may be adversely affected by spinal subluxation impinging spinal nerve axons at their exit from, or entrance through, intervertebral foramina, or by spinal subluxation producing direct impingement upon some part of the sympathetic system and similarly interfering with its power to functionate.

The Nerve System may be divided into two great divisions, the central axis and the peripheral system which distributes nerve energy from, and brings stimuli to, the central axis. The central axis consists of the brain and spinal cord; the peripheral system of 12 pairs of nerves attached to the brain and having exit (except the eighth) through foramina in the base of the cranium, 31 pairs of spinal nerves emerging through intervertebral foramina whose parts are movable upon each other (except the foramina for sacral and coccygeal nerves), and an intricate system of sympathetic fibres and ganglia arranged in a double chain of ganglia in front and at the sides of the vertebral column, three great prevertebral plexuses, the cardiac, coeliac, and hypogastric, and numerous scattered ganglia and communicating cords which bind the ganglia together and connect them with spinal or cranial nerves and with the periphery.

The peripheral system is somewhat complex and numerous intercommunications are established by which nerve impulses originating in the central axis and leaving by one part of the peripheral system may exercise a controlling influence over another part. Plexuses, or intertwinings of nerve axons, are so numerous and complicated that it is difficult to follow each set of nerve stimuli from their origin to their final destination and effect without considerable study.

Direct Distribution of Spinal Axons

The spinal nerve axons, taken as a whole, establish paths between the motor gray of the ventral horn of the spinal cord and all voluntary muscles of the body below the head except the trapezius and sternomastoid, partially innervated by the eleventh cranial, and between the sensor cells of the dorsal spinal gray and gracile and cuneate nuclei of the medulla on the one hand and the sensor end organs in skin and mucuous membrane, muscles, tendons, and joints on the other. The ventral cornu receives impulses from the cortico-spinal axons of the direct pyramidal, crossed pyramidal, rubrospinal, and other smaller tracts which bring the spinal gray under the direct voluntary domination of the volitional centers in the brain or of the indirectly voluntary pathway through the cerebellum. The spinal nerves are the direct media for motion of the body or its parts in relation to its environment. The sensor gray of the cord is similarly in communication with the conscious sensation area in the cerebrum and with the cerebellum by way of the dorsal tracts of the cord, the lemnisci, and the cerebellar peduncles.

In the main these nerves of motion and sensation are arranged as follows:

The Cervical plexus is composed of the intertwining of axons from the anterior primary divisions of the four upper Cervical nerves. Its branches pass to and innervate many voluntary muscles of the neck and side and back of head, and supply sensor fibres to the adjacent cutaneous areas. Branches also communicate with the last three cranial nerves and one long branch, the Phrenic, or Internal Respiratory Nerve of Bell, passes through the neck and thorax to the diaphragm, as its motor nerve.

The Brachial plexus is made up of the anterior primary divisions of the four lower Cervical nerves and the greater part of the first Thoracic. It is distributed chiefly to the voluntary muscles and integument of the shoulder and arm, forearm, and hand, but sends branches to some muscles of the neck and upper back as well. It, like the Cervical plexus, receives branches from, but gives none to, the Cervical sympathetic.

The Thoracic nerves are not arranged in plexiform fashion like those above but pass separately, for the most part, to their destinations. They are distributed to the walls of the thorax and abdomen following the curve of the ribs in direction. The last Thoracic sends one division downward as far as the outer aspect of the ilium.

The Lumbar, Sacral, and Pudendal plexuses are formed of the ventral divisions of the Lumbar, Sacral, and Coccygeal nerves and distribute branches to the integument and voluntary muscles of the lower abdomen, pelvis, and lower extremities. From two of the sacral nerves branches known as “Visceral” pass through the plexus to terminate in the walls of the uterus and rectum.

All of the thoracic nerves and the first and second, sometimes the third and fourth, lumbar give off branches to the sympathetic ganglia, known as white rami communicantes.

Direct Distribution of Cranial Nerves

The distribution of the 12 pairs of cranial nerves is not so definitely to voluntary muscles and to areas from which conscious sensation is to be derived as is the case with the spinal, although the cranial nerves present many analogies with the spinal and there is abundant reason for considering them as in one series of 43 pairs. There is direct distribution of some cranial nerve fibres to secreting glands, but these fibres are probably merely derived from sympathetic trunks and carried in company with the axons of cranial origin. There is also some direct distribution of cranial nerve axons to visceral walls made of non-striated muscle, as in the case of the vagus distribution to the respiratory and alimentary tracts and that of the spinal accessory to the heart. This is a resemblance to the sympathetic.

The cranial nerves carry afferent impressions from the special sense organs, except those of the sense of touch, which function is divided with the spinal nerves.

Various intercommunications exist between the cranial and sympathetic divisions of the peripheral system, by means of which axons starting with one division may be finally distributed with another, or by which an axon of the sympathetic may pass to one of the sensor ganglia of the cranial system and influence its nutrition and condition, and therefore its power to act. There is a limited intermingling of spinal fibres with the lower cranial.

Distribution of Sympathetic

The sympathetic system directly innervates most of the nutritive or vegetative system, the alimentary tract and its accessory organs, the vascular systems, the genito-urinary system, and the ductless glands. To a limited degree it shares this control with the cerebro-spinal and to a much greater degree it brings the central axis into indirect connection with these viscera.

Gray says, “The distinction of the sympathetic system from the cerebrospinal system is made merely for reasons of convenience. The two systems are intimately connected and the sympathetic is morphologically a derivative of the central axis disseminated in connection with the nutritive apparatus and establishing relationships among the vegetative organs.”

Structure of Nerve Pathways

Most pathways which carry nerve impulses from their origin or inception to the organ in which they are finally expressed as action of some sort or translated into sensation or into stimuli which pass out reflexly over a connected neuron, are composed of more than one neuron. The neurons of a nerve pathway are arranged end to end with the axons all pointing in one general direction so that the nerve energy travels always in the same direction over the entire nerve path. Impulses are transferred from the first neuron in the chain to the second, and from second to third, etc., by contact of the telodendria of the one neuron with the dendrites or receptive processes of the next. Part of the nerve pathway may be within the central axis and part within the trunk of a peripheral nerve.

Several peripheral pathways for afferent impulses may be joined to an efferent pathway so as to complete reflex arcs and the efferent cell be under the controlling influence of some upper neuron coming down from the central axis with the power either to permit or to inhibit the reflex acts which would otherwise take place as a result of peripheral stimuli. Several such lower cells may be under the domination of one upper neuron.

In some instances the nutrition of ganglia or nerve trunks, or of parts of the central axis itself, is under the control of sympathetic neurons terminating in connection therewith, so that interruption of the normal action of the sympathetic neuron may be followed by effects manifested through some distant part of the cerebrospinal system. In the following pages we shall discuss nerve pathways with reference to the explanation of diseases caused by vertebral subluxation impinging nerves either by tension or constriction, and therefore our grouping of parts will differ somewhat from any anatomical or physiological grouping with another object in view.

Important Nerve Pathways

To brain: C 2, 3, or 4 to superior cervical ganglion by direct impingement, through internal carotid nerve to sympathetic plexuses following branch arteries from Circle of Willis. The blood-supply of the brain is under control of the cervical sympathetic and most brain lesions or diseases are due to vascular changes leading to anaemia, hyperaemia, inflammation, or hemorrhage.

To meninges: Loop between first and second cervical nerves to trunk ganglion of vagus and through meningeal branches of vagus (P), or by way of internal carotid nerve to pial sympathetic plexuses. (P) The connection of the first, second, or third cervical with cerebral meningitis is established clinically but there is still doubt as to the explanation.

Eye and Muscles, Retina, Optic Nerve: The external muscles of the eye, the four recti and two oblique with the levator palpebrae superioris, are innervated by the Oculomotor, or third cranial, and the fourth and sixth cranial, which receive branches from the cavernous plexus of the sympathetic derived from the internal carotid branch of the superior cervical ganglion. As the ganglion lies in front of the transverse processes of the second, third, and fourth cervical vertebrae, direct impingement upon it by subluxation of one of these vertebrae may cause strabismus or other affection of the external ocular muscles.

The eye-ball receives filaments from the ciliary or ophthalmic ganglion, which in turn is connected with the cervical ganglion by way of cavernous plexus and internal carotid nerve. This pathway controls the radial fibres of the iris and dilates the pupil as a part of the light accommodation reflex mechanism. Loss of pupillary reaction, especially with small pupils, suggests upper cervical subluxation.

The retina, containing the cells of origin of the optic nerve axons and being the special end-organ of the sense of sight has no direct spinal or sympathetic connections but its blood-supply, and therefore its nutrition, is influenced by branches from the sympathetic which enter with the central artery of the retina. Retinal hemorrhage has been cured by cervical adjustment, C 2, 3, or 4.

The conjunctiva is innervated by the sympathetic and by the fifth cranial, or trigeminal.

Olfactory Nerve: Nerve of smell, distributed to the Schneiderian membrane over the upper portion of the nasal septum and over the upper lateral wall. There is no known connection by which the trunk of the olfactory nerve can be reached by adjustment but the condition of the special end organs in the membrane and their ability to functionate depend not only upon the integrity of their axons but also upon the nutrition and moisture of the membrane in which they are embedded. This is under the control of the Vidian nerve and of branches from the spheno-palatine, or Meckel’s ganglion, both connected with the carotid plexus of the sympathetic and therefore responsive to adjustment of C 2, 3, or 4. This is also the route by which epistaxis is usually checked.

The external nasal muscles, like those of the rest of the face except some of the muscles of mastication, get their supply from the facial nerve, which connects with the sympathetic plexus on the middle meningeal artery. It may be said parenthetically here that peripheral facial paralysis (Bell’s palsy) yields to adjustment and proves the value of this connection. The nasal integument is under the sensor control of the trigeminal and trophic disturbances may result from its involvement.

Trigeminal Nerve: This is the great sensor nerve of the face and carries a motor division, the inferior maxillary, to some of the muscles of mastication, as the temporal, masseter, and buccinator. It has connected with it four ganglia, which also receive sympathetic roots, and the ganglion of origin of its sensor axons, the Gasserian or semilunar, also receives direct sympathetic communications. The importance of this communication is shown by the powerful effect of adjustment of third or fourth Cervical for tic dolouroux.

Ear: The external ear receives branches from the vagus and from the first and second cervical nerves. The middle ear and Eustachian tube are supplied by the tympanic plexus made up of branches from the glosso-pharyngeal, otic ganglion, facial nerve and the small deep petrosal from the sympathetic on the carotid artery. By all these routes communication from the third and fourth cervicals is possible but especially is the latter important. The fourth cervical is the especially frequent subluxation with middle ear disease. To the internal ear and auditory or acoustic nerve there appears to be no direct route from the spine. It has not yet been conclusively established within the writer’s knowledge that adjustments will affect auditory deafness but Meniere’s Disease, inflammation of the semicircular canals, has been cured repeatedly by adjustments of Atlas or Axis, by what route I am unable to state.

Teeth and Gums: It is probable that the only connection between the vertebrae and the teeth is an afferent one by way of the trigeminal. Toothache may be stopped by adjustment of C 3, or C 4, but no evidence is at hand to show that the condition of the teeth is improved or that more than a temporary effect can be had. Trophic changes in the gums may be due to vascular disturbances controlled by the sympathetic.

Tongue: The hypoglossal, motor nerve to both the intrinsic and extrinsic muscles of the tongue, receives direct axons from the loop between the first and second Cervical nerves. Sympathetic fibres pass to the blood-vessels and secreting glands of the tongue.

Tonsils: Receive fibres from the spheno-palatine ganglion and by this means are brought under the domination of C 2, 3, and 4. Abundant clinical evidence in tonsilitis, simple, follicular, and suppurative, proves this to be the practically, as well as anatomically, correct nerve connection.

Salivary Glands: The parotid receives branches from the great auricular nerve from the second and third cervical, and from the sympathetic on the external carotid artery, branches from the superior cervical ganglion. The submaxillary and sublingual glands are connected with the submaxillary ganglion, which receives a sympathetic root and which, with the chorda tympani also carrying fibres derived from the sympathetic, controls the secretions of these glands.

Pharynx: The pharyngeal plexus is a mixture of sensory axons from the glosso-pharyngeal, motor components from the vagus and probably sensor from the same nerve, and sympathetic branches from the superior cervical ganglion. All of these may be influenced by the upper cervical adjustment.

Larynx: According to anatomy the larynx is innervated by the superior and inferior, or recurrent, branches of the vagus and by sympathetic branches from the superior cervical ganglion. Clinically the sixth cervical adjustment cures laryngitis and aphonia. The explanation probably lies in the fact that the thyroid branches of the middle cervical ganglion, lying in front of the transverses of the sixth, communicate within the thyroid gland with the recurrent laryngeal and with the external laryngeal branch of the superior laryngeal.

Thyroid Gland: “The nerves to the thyroid are amyelinic and are derived from the middle and inferior ganglia of the sympathetic.” (Gray.) The middle cervical ganglia are situated in front of the transverse processes of the sixth cervical vertebra. Clinically, the sixth cervical reaches goitre.

Muscles of Neck: The platysma is supplied by the facial nerve; the sternomastoid by the spinal accessory and cervical plexus; the infrahyoid region by the first three cervical nerves; the suprahyoid region by the facial and the ansa cervicalis; the anterior and lateral vertebral muscles by the cervical nerves from second to seventh inclusive, but especially the second, third, and fourth. It will be seen that muscular disturbance in the neck may result from any cervical subluxation. Torticollis, which usually involves the sternomastoid, yields to the second cervical most frequently.

Lymph Nodes of Head and Face: These lymph nodes are controlled by the cervical sympathetic. Pathological changes in one or more nodes requires careful cervical palpation to determine the presence of a subluxation away from the affected side.

Muscles of Back: The trapezius is innervated by the spinal accessory and by the third and fourth cervical nerves; the latissimus dorsi by the sixth, seventh, and eighth cervical through the middle or long subscapular. Occasionally a tender nerve, traceable from the lower reaches of the latissimus to the cervical region has mislead the practitioner into imagining a cervical connection over the back with internal viscera.

The second layer of the back is supplied by the third, fourth, and fifth cervical nerves. The third layer is innervated by the middle and lower cervical and upper three thoracic nerves except the serratus posticus inferior which is supplied by the ninth, tenth, and eleventh thoracic. The fourth and fifth layer are supplied by the posterior primary divisions of the spinal nerves and any given section of these layers may be traced to a vertebra directly above, or cephalad.

Thoracic Walls: The parietal muscles of the thorax are innervated by the intercostal nerves and a very definite segmental association with the spine is traceable.

Diaphragm: Phrenic nerve, which arises from fourth cervical chiefly; lower intercostals, especially eighth and ninth; and phrenic plexus of the sympathetic which may sometimes be reached from the fourth or fifth dorsal vertebrae through the gangliated cord. For motor disturbances of the diaphragm adjust fourth cervical.

Abdominal Muscles: These are supplied by the lower intercostals and the transversalis and internal oblique make connection with L 1 by the iliohypogastric. Cremaster is supplied by L 1 and 2 by way of the genital branch of the genitofemoral.

Perineal Muscles: The anterior perineal group are supplied by the perineal branch of the internal pudic which traces to the second, third, and fourth sacral nerves. The posterior perineal and ischiorectal region is also supplied by the sacral and coccygeal nerves.

Trachea and Bronchi: Vagus and sympathetic filaments from first and second thoracic ganglia. The latter receive preganglionic fibres from first dorsal nerve in all probability, as this adjustment reaches the bronchi.

Lungs: The third thoracic ganglia connect with the pulmonary plexus and establish a connection from third dorsal vertebra direct to the lung parenchyma. The Pleurae have a similar connection or may sometimes be reached by the first dorsal.

Heart and Pericardium: In 55% of all heart disease or improper action the second dorsal is responsible; in 40% the first dorsal, and perhaps in the remaining 5% the atlas or axis. The former nerves (T 1 and 2) furnish pre-ganglionic fibres which stream upward through the gangliated cord to terminate in the three cervical ganglia in relation with the dendrites of new neurons (amyelinic) which form the superior, middle, and inferior cardiac nerves and pass into the thorax to mingle with vagal fibres to form the superficial and deep cardiac plexuses, controlling the heart. Probably the upper cervicals occasionally affect the vagus through the loop between the first and second cervical nerves.

Thoracic Aorta: Controlled by sympathetic from first thoracic ganglion or last cervical ganglion, and thus by seventh cervical or first dorsal vertebra.

Abdominal aorta—Coeliac Axis: The upper portion of the abdominal aorta is innervated by the coeliac or solar plexus of the sympathetic. Sub-plexuses from the coeliac accompany the various branches of the aorta and are widely distributed to the blood-vessels and to the glands and non-striated muscle of the abdominal organs. The coeliac plexus receives fibres from the right vagus and from the greater, lesser, and least splanchnic nerves, by the latter route making connection with the thoracic ganglia of the sympathetic from fifth to last. These ganglia receive pre-ganglionic fibres from the thoracic spinal nerves in the form of white rami communicantes, so that it is not incorrect to say that the coeliac plexus and its branches are largely controlled by the condition of the last eight thoracic nerves.

Through this intricate plexus it is difficult to trace the relations of each abdominal organ with the particular vertebrae of which subluxation would produce disease in said organ. By the aid of clinical experimentation covering a period of years and by diligent search among anatomies and physiologies, we have arrived at the conclusions indicated in succeeding statements.

The most important spinal connection with the abdominal blood-vessels is that of the fifth dorsal vertebra, for the fifth dorsal nerve, by its rami, seems greatly to influence the caliber of the aorta and coeliac axis.

A. Cortico Spinal nerve. B. Spino Ganglionic nerve.
C. Ganglio Ganglionic nerve. D. Ganglio Peripheric nerve.
E. Blood Vessel Wall.