[NOTE: THE FOLLOWING SECTION IS EXCERPTED FROM PRINCIPLES & TECHNIQUES OF NERVE REGENERATION  BY DAVID MCMILLIN] 
    As illustrated in the preceding excerpts, when speaking of coordinating treatments, Edgar Cayce often mentions "centers" along the spine.   Understanding the concept of centers is essential for the application of regulative treatments.  In other words, there are nerve centers for coordination and drainages.  It is necessary to know where the centers are and how to therapeutically influence them.
      The concept of centers is inherent in the osteopathic model of treatment.  From the beginning of the profession, osteopathy recognized the significance of certain nerve ganglia as important centers which influence and regulate the vital processes of the body such as circulation, assimilation and elimination.  The excerpts which follow are from the early osteopathic literature.  Note that specific nerve centers regulate vital physiological processes.  Also note the frequent references to the coordinating role of centers:

    "Know the location of the centers.... Our use of the term center is in the sense of a convenient and advantageous place to reach fibres to or from a certain organ."  (Riggs, 1901, pp. 21-22)

    "We all agree upon the one great point, that man is a machine, and that nerve-centers have been discovered upon which a pressure of the hand will cause the heart to slow or quicken its action, from which we can regulate the action of the stomach, bowels, liver, pancreas, kidneys, and the diaphragm. The thousands of people snatched from the grave by an application of these never-failing principles are proof positive that at last the keynote has been struck; and a school [osteopathy] established that can explain intelligently why certain manipulations produce certain results."  (Barber, 1898, p. 28)

    "Certain points on the surface of the body are spoken of as "Centers."  This word has become a part of the osteopath's technical vocabulary.  It does not convey to the mind of the osteopath the same meaning which attaches to it when used in physiological text-books.
    A physiological functional center in the central nervous system is that point where the action of a certain viscus or other structure is governed.
    An osteopathic center is that point on the surface of the body which as been demonstrated to be in closest central connection with a physiological center, or over the course of a governing nerve bundle....  No portion of the nervous system ever functions absolutely independently.  The action of every portion affects all other portions, but certain areas in the brain and spinal cord seem to be somewhat set apart to govern or coordinate the physiological activity of certain organs.  Physiology has demonstrated a large number of these centers."  (Tasker, 1903, pp. 178-179)

    "Physiology and Pathology demonstrate that impressions made upon sensory elements in skin, mucous membrane, muscle, or other structures, are carried to a center in the central nervous system.  These impressions are coordinated in this center, and affect the physiological action of all structures innervated from the same center."  (Tasker, 1903, p. 180)

    "After the publication of the results of Sherrington's experiments, especially those in which he had been assisted by Alexander Forbes, the clinical evidence that had been collected by the founder of osteopathy and his early followers took more definite form, and certain well established facts may now be offered for laboratory proof:
A.  The presence of definite centres, by which are meant areas at which stimulation may most speedily secure effect upon the final common efferent neuron.
B.  The presence of secondary centres, points at which, following fatigue of the synapse from stimulation at a primary centre, excitation will promptly bring a response from an organ or tissue.
C.  The production of vaso-motor reactions which assist in establishing immunity, through overcoming the persistence of conditions which invite infection and through changing the specific properties of the blood so that antibody formation is hastened and disease limited."  (Ashmore, 1915, p. 223)

    Note that in the last quotation from Ashmore, there is the idea of primary and secondary centers.  The Cayce readings also recognized a hierarchy of centers.  The readings sometimes referred to the primary centers as "coordinating centers" in reference to their fundamental role in homeostatic regulation.
    From the perspective of Cayce's hierarchy of centers, the three primary centers of interest in manual therapy are located at the 3rd cervical, 9th dorsal (thoracic) and 4th lumbar.  These are also the centers where the  electrical appliances such as the Wet Cell Battery were most often attached to the body.  These are the centers which Cayce insisted that the osteopaths coordinate with their treatments.  These are the centers where the readings recommended that persons doing "magnetic healing" ("laying on of hands") should put their hands.
    In a more metaphysical vein, these key centers were cited as important "spiritual centers" where the spirit and soul forces were influential in the physical body.  These centers were associated with the flow of the "life force" or kundalini energy:

 ... the 3rd cervical ... the 9th dorsal ... the 4th lumbar .... These are the three centers through which there is activity of the kundaline forces that act as suggestions to the spiritual forces for distribution through the seven centers of the body.       (3676-1)

    Hence we find there are specific centers where the [nervous system] incoordination is shown; as in the lumbar (4th to 2nd), the 9th dorsal and specifically the 1st, 2nd and 3rd cervicals.  These are centers where the coordination between the impulse and the physical activity produces periods when there are the associations with not only the mental and physical but the spiritual activities - or the source of the ENTITY [SOUL] itself in its connection with the physical body.       (1087-1)

    Those tensions to be released in the physical forces of the body, in those centers where there are the coordinating forces between the mind and the physical reactions, - which are those centers through which the nerve forces in the sympathetic centers coordinate with the cerebrospinal or the central nervous system; or the spirit and mind system with the physical organism, - 9th dorsal, 4th lumbar, and throughout the cervical areas.       (2528-2)

    Thus the significance of these major centers is not only that they help to coordinate the nervous systems and the vital processes of the physical body, but they are centers of coordination between the physical, mental and  spiritual dimensions of the "ENTITY" or soul.  In this context, coordination takes on a more expansive, holistic meaning.
    Other important nerve centers along the spine are found at the coccyx (tailbone), 5th & 6th dorsal (cardiac plexus), and 1st and 2nd dorsal (brachial plexus).  By manipulating these and other nerve centers throughout the body, traditional osteopaths were able to assist the body in establishing health.