That curvatures of the spine are due primarily to dynamic and not static causes may be proved in the following manner:

    Patient prone; operator lifts legs (holding above knees) to angle of thirty or forty degrees; places heel of hand against convex side of curve and presses toward concave side while rotating raised legs from side to side in wide sweep. This technic if properly done will change the one long curve into a series of short ones; or may completely reverse it.  There is the same total amount of curvature, but instead of being one long curve it is a series of short ones.  This is not possible in all curvatures, is easiest in those involving the lumber region and is no longer possible after structural changes have been caused in the bones.

    Curvature may thus be due not to contracture of muscles of one side, either convex or concave side, but to shortening of the muscles of both sides, until they are shorter than the spine; or else to swelling of the discs until the spine is longer than the muscles.  (Burns, A. O. A. Journal, July, 1917.)  In order to get the greater length of bone within the limit of the lesser length of muscle, the spine curves on itself.  The etiology of this muscular shortening is doubtless the same as that of neuralgia, etc., the one motor, the other sensory.  Curvatures may also arise from unilateral contractures.

    Having determined this etiology, it then follows as a matter of course that there are similar conditions involving lesser parts of the column.  These we find in great abundance.  The chief seat of these changes and the smaller curves that they give rise to is the fourth dorsal segment.  This condition is so frequently found that it might almost be said to be typical of most of the spasmodic disorders and most of the sensory as well, of many of the disorders of internal secretion and disorders of the stomach and the brain.  A large field; and yet I feel sure that it will be broadened rather than narrowed as experience accumulates.  The condition it gives rise to should be called technically a curve, even though it may not take the shape of a curve; this to make a necessary distinction between those conditions due to muscular spasm or disc changes, and those due to acute lesions or to weakenings (warps) as well as from conditions like Potts disease.

    These conditions may appear anywhere in the spine.  They are most frequent at the fourth dorsal, as said, where the distortion they produce may be a curve, three or four vertebrae long only, or may lead to acute lesion of some one point, as the rib, or to other forms of distortion.  The next most frequent site of them appears to be between the third cervical and the occiput on the left side—and these occur almost invariably in connection with strain or disorder of thyroid function.  The effect of this contracture, if mild, is merely to cause lesion of the third cervical; but may go so far as to squeeze atlas and axis some distance to the opposite side, the right.

    In other cases, the rectus capitis lateralis on one side alone may be involved, approximating that side and separating the opposite side.

    The next most frequent sites are in the neighborhood of the eleventh dorsal or the eighth dorsal.  As all of these points are specific centers for organs of internal secretion, the close connection of such conditions with strain of these organs is evident.  They may occur at any point, however.

 
TECHNIC

    The technic of these conditions is first the correction of the primary condition, and second the persistent passive stretching of the contracture itself, which may be aided by posture, even posture enforced by straps, casts, etc.  The Lovett technic may be used.  See also Ashmore’s Osteopathic Technic.

 
GROUP LESIONS

    It is in the handling of group lesions that the highest diagnostic skill of the operator is displayed.  It is soften impossible to distinguish group lesions from warp lesions; and yet the distinction is highly important.  Warp lesions may be made to correct themselves by change of habits and by exercises, though this process is made a hundred times as rapid by assistance of the operator.  But group lesions are like the log jams in Northern rivers.  Unless the key to the situation is discovered, and corrected, the whole condition will recur; the operator may correct the secondary lesions as many times as possible, they—or others—will recur in time.

    Group lesions must also be distinguished from lesions due to spastic conditions of parts of the muscular column, or thickening of discs, i.e., curves.

    The general principle of group lesions is perhaps most easily seen in case of lesion of the sacrum (or as it is more often called, lesion of the inominate).  The sacrum sinking forward on one side offers a tilted base for the vertebral column above it.  The body of the fifth lumbar sinks on the inclined plane, and its spine is usually found deviated toward the same side (since the center of rotation is posterior to the spine, the spine will be deviated to the same side as the body of the vertebra, though to a lesser degree).  The whole lumbar column is thrown off of its normal balance, toward the side of the lesion; and the effect is transmitted through the lumbar articulations which are strong laterally, to take effect on the first articulation that lacks this lateral strength, the eleventh dorsal; whose articular plane is not antero-posterior, but transverse.  The eleventh and twelfth ribs may then become involved in the tangle, which may continue to spread indefinitely.

    But though compensation is thus made in part for this unbalance, yet it is evidently not completely made; for according to Dr. F. C. Morris, lesion of the atlas almost invariably accompanies lesion of the sacrum—a thing not necessarily significantly at first sight, but becoming significant when we learn that the deviation of the atlas is always on the same side as the sacral lesion—that a sacrum anterior throws an unbalance upward through the spine whose last effect is the throwing anteriorly of the occiput of that side—called a posterior atlas on that side.  He further states that unless the sacral lesion be corrected the atlas lesion will recur.

    Dr. Edyth Ashmore, examining the vertebrae of human skeletal in museums, found that evidence of lesion could be read in the articular surfaces.  Studying this evidence, she found that lesions alternated through the spine.  A lesion to the left of, say, the seventh dorsal produced a compensatory lesions to the right of the sixth, to the left of the fifth, of lessening degree, to the right of fourth, etc.

    Examination of spines in the classes of the A. S. O. referred to above disclosed the fact that this alternation ran not only upward, but downward as well, also that whereas usually the alternation went from one vertebrae to the next, yet often lesion was great enough to cause two vertebrae to deviate to the opposite side, the next two to the same side, etc.; or in rare cases, where the rhythm of the compensation was greater than one and less than two, the deviation would be irregular.  Obviously it would be an error to correct any but the first of these, until after the first had been defined and corrected.  Until one’s conception of the mechanics of the spinal column has become sufficiently clear from long practice, one’s only guide is the relative soreness of the various joints—not a perfect guide—and his knowledge of specific centers.

    Rib lesions are held by some to be always necessarily accompaniments of vertebral lesions.  This I believe to be an error, though perhaps a justifiable one.  Deviation of the rib belonging to a given vertebra is necessary if the vertebra is in lesion; and by this deviation strains of various sorts are set up through the muscles and ligaments connecting that rib with adjacent parts, with resulting secondary deviation.  But these deviations are compensatory, or at best secondary, and their correction must follow that of the vertebra, never precede it.  That lesion of ribs may occur independently of lesion of vertebrae is, I believe, an accepted principle.

    In warp lesions, secondary warps are the rule.

    From any structural deviation in the body secondary and tertiary and still further changes are apt to arise; are almost sure to arise in time.  It is a principle of mechanics that a strain will diffuse itself until it finds equilibrium.  In the self-adjusting structure of the living body, such a tangle may spread very widely.  But the activity of the said body may even cause a continuous aggravation of a primary slight disorder without limit.

 
WARPS

WARP LESIONS

    By warp is meant deviation due to habitual posture or exercise in different occupations; not necessarily involving fixity or acute lesions, but tending to produce both.  They are easily corrected but quickly recur unless their cause is removed.  They are of the greatest variety, but the most typical is the posterior sag of the lumbar spine due to the habit of sitting long hours over school desk or books.  Probably ninety per cent of educated human beings suffer from this deformity.  In the formative years, the period of growth, the body is peculiarly liable to warps from posture.  These may in time correct themselves, under changed habits, but they do not do so in all of that ninety per cent by any means; and in any case they leave a weakness and a tendency to recurrence.  But in many cases they produce acute lesions and even structural changes that are permanent.

    It is impossible to overestimate the amount of damage that this fault in our educational methods does to life and health.  Too often it is a case of education versus  health or even life.  It is usual that by such inconspicuous but omnipresent factors the greatest total of damage is done.  It is so in this case.  Children were not meant to spend interminable hours over books during the years when they should be training the subconscious mind in the geometry of the moving hand and the swinging pendula of the limbs, etc., that great source and background of all of our conscious thought.

    The effect of such a warp is to produce limitation to motion in various directions, and so to increase the likelihood of lesion at either end; also to bring focal strain on some point near the center thereof, with similar increased likelihood of lesion.  The posterior lumbar sag, for instance, may reach as high as the eighth or seventh dorsal; and at that point, or wherever the upper limit of the sag happens to be, is usually found a lesion; due to the fact that the spine in the flexed position of the warp has lost its lateral flexibility; concentrating a strain of that kind on the joint at the end of the warp.  The same thing is true of the lower end, which is almost always the fifth lumbar, hence the very great frequency of lesion there.

    The way in which warps are produced is most easily seen in the upper cervical segments.  Here warps are produced by posture in sleeping; and it is usually possible to tell the position in which a patient sleeps from the position of the upper cervical vertebrae.  Thus in sleeping on the back with the head raised on a high pillow the occiput is drawn forward, and the atlas is found prominent back of the mastoid line.  In sleeping for long hours in this position the ligaments become stretched, and the muscles of course relaxed; and the bones become displaced simply in the direction of the strain.  They tend to recover as soon as normal use and normal position is restored, but when the same strain is repeated night after night they become established in the false position.

    Thus gradually assumed, there is less irritation from the immediate lesion itself than in the case of an acute lesion; but diseases are in fact found to arise from it, and to be corrected by the correction of the disorder.  Warpings of the body are so many times more numerous than acute lesions that probably a greater total of ills arises from them.

    The same technic that is available for acute lesions is available in warp lesions, insofar as they affect single vertebrae; but warp lesions usually cover an area rather than a single segment, and must be treated accordingly.  Any technic that offsets the false position is available, unless acute lesion has occurred.  For flexion warps the proper technic is extension, etc.  It is best applied first passively, and then in the form of regulated exercise.

    In dealing with inanimate objects, fences, wheelbarrows, machinery, it is comparatively easy for the mind to grasp the mechanical principles, and to follow them successfully through their changes.

    But in dealing with the human body it is not thus easy.

    In the first place, the mechanical parts are concealed.

    In the second place they are extremely complicated; practically all mechanical principles apply at all points.

    In the third place there is much individual variation.

    In the fourth place, it is a living human body lying there, possibly in state of extreme suffering; and this does in fact make much more difficult, and sometimes extremely difficult, the matter of concentrating the ;mind on the purely mechanical factors in the condition.  Yet on the physician’s capacity to so concentrate may depend the life of that person.

    It is quite necessary then that the faculties dealing with the mechanics of the body be trained to the last possible degree, until knowledge and technic are almost unconscious—until perception has become almost an intuition.