It is rarely that disease arises from one cause only.  Nor is it possible to choose among the many causes and say which is primary and which secondary, except in time.  All causes acting at one time are responsible causes, “procuring causes” as the legal phrase is.   Mechanical lesions are, however, always fundamental and determinable.

    Analysis of mechanical factors in disease so far as at present understood shows that they may be divided into several classes as follows:

    Osteopathic
    Myopathic
    Neuropathic
    Visceropathic, etc.

    The reason for so dividing them is that they need to be separately studied, since they require different forms of treatment.

    Osteopathic lesions, much the most important, will be discussed last.

    Myopathic lesions are those in which contracture of muscles is the cause of further disorder, is the mechanical factor that needs to be removed.  These may be themselves secondary, or may be merely a part of the whole abnormal condition; that seems to make no difference in the effect.  The removal of this part does in fact relieve, or tend to relieve, the whole, and to react on the primary condition from which it arose.  The discussion of that fact is a matter for the subject of principles.  We are here concerned with the technic for removing such contracture.

    (The word contraction is used to indicate normal contraction; contracture is used to refer to the pathological continuance or exaggeration of contraction.)
 
 

    All living tissue is contractile.  The contraction of areolar tissue ;may be at times surprisingly vigorous.  Under the irritation of shock, as from a blow or cold,  etc., it shows itself.  It may remain long after the cause has been removed.  In that state it becomes a cause of trouble in nerves and in venous and lympathic drainage.  This humble and ignored kitchen-drudge tissue of the body has some highly important functions.  Normally it is in a  state of slight contraction.  It holds the skin in position so that it does not drag and stretch by its own weight.  It holds the skin against the under-lying structures so that it prevents accumulation of lymph, etc.; it guides the lymph along to the opening of the lympathic ducts and aids it to enter.  It adapts itself to variations in atmospheric pressure and in position.  In inflammation, it contracts vigorously around the inflamed area, being sufficient to seal up the part and prevent the diffusing of the inflammatory exudates; so that it acts to circumscribe inflammation; and in so doing converts the part into erectile tissue; whence the swelling.  In wounds it prevents the escape of lymph and helps to close up injured blood vessels.

    When so occurring it is likely to remain almost indefinitely, as though it lacked the power of spontaneously relaxing.  It is when thus remaining contractured that it becomes a source of mischief.

    The effects of its contraction are in line with its function.  It overdoes that which is normally its work.  It has in normal tissue the effect it should have only in wounds, etc.  It checks the lymph, retards the blood, numbs the nerve terminals, prevents the easy adjustment of part to part and so causes friction, etc.

    There are certain areas of the body where this tissue is especially abundant, where such disorders are of greater relative frequency, which should be mapped out and studied; as for instance the back of the neck.

    The relaxation of such tissue is best accomplished by manipulation beginning gently and increasing gradually, so as not to rupture the delicate fibres.  A sense of coldness and of resistance may be noted, and a distinct though vague sense of comfort like that from removing tight clothes is noted by the patient.  Around bruises or boils, etc., there is an area more or less wide-spread of such contracture.  By beginning far enough away and gently enough and approaching gradually nearer the injured part, one may often in a few minutes handle it with ease and practically without pain, and greatly improve lympathic and venous drainage and nerve tone.  After fractures, sprains, etc., it has been found that such relaxation of areolar tissue hastens recovery markedly.  Hot applications may be used to numb the nerves if necessary, after which manipulation will be found to give much less pain.

    The treatment is of course contraindicated in focal infections and bleeding wounds.
 

    For the relaxation of contracted muscle there are three mechanical methods:  manipulation (rhythmic stretching with the hand) stretching (by passive movements of the body) and inhibition (pressure with the hand, on the muscle or its nerves).  To this may be added exercise, to promote functional relaxation.

    Five minutes of massage will exhaust temporarily any normal muscle.  From one to two minutes is all that is usually required to relax single muscles in contractured states.  The time that it takes to get this relaxation is a rough measure of the depth of the pathological excitation.

    The difference between these methods is not very great, and the one that should be used is more a matter of the convenience of the operator and the patient than that of pathological indication.

    Probably the best method is a combination of the three.  Placing the patient in a comfortable and relaxed position such that the contractured muscles are extended but not to their fullest extent, apply pressure to the muscle while extending it further, for three or four seconds, then release for a second or two, and repeat, until the muscle is found to relax.

    Students should practice with a dynamometer at their side until they can gauge the amount of pressure they are applying.  In no other way can they criticize or standardize their own work or successfully compare it with that of others.  Rarely as much as ten pounds need be used on the neck, in adults; more in the back, still more in the lumbar region.

    Where muscles are found to be sore, manipulation should be gentler at first, increasing in weight; should be farther away, approaching nearer the focus of disorder, as the pain diminishes under the manipulation.  The pain should disappear under the treatment, or shortly after.  The reaction time of the sensory nerves measures the reaction time of the nerves involved in the pathological condition, so that when the change has occurred in the one, it will be found to have occurred to some degree at least in the other also.

    Failure to secure results in such treatments is due first  to failure to secure perfect relaxation.  It should not be prolonged beyond the point of relaxation, but should not be left until at least some relaxation is secured.  Dr. Tyndall states that “We often miss the whole effect of a treatment because w do not make it a point to secure perfect relaxation at the segment treated.”

    Failure may be due also to ignoring of the deep muscles of any given segment.  These are apparently the ones most affected and closest to the nerve centers involved.  When the more superficial muscles have relaxed, the examining finger should pursue the investigation to the deeper tissues, until the whole palpable area of the segment has been outlined and relaxed—short always of overfatigue of the nerves.  The normal uncontracted muscle should be almost unpalpable—as soft as the cheek.  In very thin persons the tendons of spinal muscles will often be mistaken for contractured muscle fibres.  Often after treating a certain area a short time and leaving it for some other point and then returning, the first point will be found to have become relaxed.  It is best always to return to make sure.

    In severe conditions heat may be used to aid in relaxing.  Heat tends to produce a paretic condition of blood vessels, cold to produce a spastic condition of them; and the effect on muscles is of the same kind.

    Knowledge of specific centers is very valuable in soft tissue treatment.  The treatment should be begun and carried to a finish first at the specific centers for the organs affected.  Other contractures may if necessary be ignored for the time.

    Frequency of treatment is a matter of the severity of the condition and the character of the disease.  Contractures will recur if the irritation from which they arise remains.  In pneumonia these recur sometimes in a few minutes or half an hour.  Short of causing unfavorable reaction from the treatment itself the tissues may be relaxed as soon as contraction recurs.  This is not always possible.  In pneumonia every hour is not too frequent, and some physicians treat as often as every twenty  minutes.  In the exanthemata the usual practice is three times a day except in more dangerous states, when it may be more frequent, graded according to the strength of the patient.  In the average chronic condition the frequency of treatment is determined by mechanical conditions of the framework.  Twice to three times a week is the average.  In asthma, once in a week or ten days is best, more frequent is regarded as hazardous.

    Relaxation as a preparation for reduction of bony lesions is by some regarded as essential.  In general it is advisable especially if the sensibilities of the patient need to be considered; but it is not always mechanically necessary.
 

    The longer muscles of the right side—erector spinae mass—will be found to be on tension; those on the left side relaxed.  The deep muscles of the left side may sometimes be stretched, according to the position of the patient.  Contractured muscles may be easily noted on the left side.

    The bodies of the lumbar vertebrae have sunk toward the table farther than the spine thereof (rotated).  It will be noted that the axes of rotation of lumbar vertebrae are posterior to the tips of the spines in general.  The articular surfaces on the left side are telescoped into each other, those of the right extended; the costal processes are approximated on the left, separated on the right.

    Standing behind the patient place one or both thumbs on the top or left side of the spinous processes and slide them forward following the contour of the bone, keeping the muscular mass in front of them, until they meet the resistance of the contractured muscle; then press them against the mass, swinging the lumbar spine forward with the pressure, and release and repeat, slowly and with graduated pressure, until the contractures are overcome.  This pressure and motion tends to separate the costal processes from each other on the left side, swinging the bodies still farther toward the table, and to stretch the muscles.  Having relaxed the larger and more superficial muscles, carry the exploration deep into the tissue between the vertebrae.

    This is effective as far up as the eighth or ninth dorsal.

    To increase its effectiveness in the lower dorsal and to carry it up into the mid dorsals, grasp the patient’s shoulder with the right hand, drawing back or merely holding, while the slow rhythmic pressure is applied with the left thumb.

    To make it effective in the upper dorsals, place the patient’s left elbow in contact with the table fairly close to the body and hold it there with the left hand while applying rhythmic pressure with the right thumb.

    In dorsal vertebrae, this pressure does not cause further extension with stretching.  Stretching is here produced by side-bending, the shoulders being carried upward.  Pressure against one side of a vertebra tends to carry it forward, but that movement is slight.  There is always enough elastic “give” to ligament, cartilage, and even bone, to insure some motion and some stretching of contractured muscle, by this alone.  But this motion  is opposed by several factors in the chest.  The articular surfaces are flat against it.  The ribs also, sustained by the pectoral muscles and the intercostals continuation of them, do not yield and so prevent rotation of the vertebra.  Lastly is the fact that the center of rotation of a dorsal vertebra is in front of the body, so that it can rotate only by carrying the rib with it.  To produce further stretching in this position the shoulder must be used to produce side-bending.

    If, however, the operator puts the fingers of his left hand on the corresponding rib at about the center and presses down and forward so as to carry the rib away from the spine, this together with the thumb pressure at the spine rotates the vertebra to the limit of its capacity; and aids in relaxing the deep muscles of that segment.

    If instead of holding the shoulder the operator carries it up so as to stretch the pectoral muscles and elevate the ribs and then applies pressure to the left side of the dorsal vertebrae, he produces side-bending with stretching, especially when the patient inhales.  As the patient exhales this may be changed into a primary rotation, with rotation downward of the rib on transverse process and between vertebral facets.

    In the upper dorsals and ribs there is very little real motion.  A slight flexion and extension; a slighter unilateral flexion and extension or side-bending; a still slighter rotation, are all that are found in the average person.  (For these reasons the articular surfaces are irregular as shown in the analysis of that subject made at the A.S.O.)

    When, however, the head is drawn back and the face turned toward the table, pressure on the left side of the vertebrae here causes the transverse processes to be separated to the full limit of their possible  motion on the left side, with corresponding motion at  all other parts, and with stretching of the muscles.

    Pressure technic is little used for the neck; caution must be exercised on account of the possible pain to the patient.

    It is not necessary to press hard enough to produce motion in all cases.  The pressure alone will ultimately relax all of the muscles that it reaches.  It is not necessary to make the pressure greater as the contraction is greater.  We are dealing with not mechanical but vital structures; gentle pressure will be pretty sure to win in the end.  Prolonging the pressure is better than increasing the force of it.
 
 

    The position of the knees has no effect on the position of the lumbar vertebrae or the tension of lumbar muscles unless they be carried high enough to produce extension of the vertebrae and tension of hip muscles; in which case it is the larger superficial muscles (erector spinae mass) that are tensed, and not the deeper and more important ones.

    The effect of the drawing on the muscles is slight as to relations of the vertebrae, producing some slight rotation and flexion of those whose muscles are drawn upon.  The chief effect is on the muscles themselves.

    To make this treatment effective in the lower dorsals, hold knees as before, and place hand on patient’s shoulder to hold or to push while drawing forward and upward on the muscles of this area.

    The effect of this, beside stretching of the muscles to which tension is directly applied, is to cause unilateral extension (side-bending) of the vertebrae at the focus of the tension, with rotation downward of the ribs unless this is offset by sufficient pressure on the shoulder to tense pectoral and intercostals muscles.

    The sasme technic applied to the ribs causes rotation downward or upward according to the tension on the pectorals and intercostals, and with respiratory movements, stretching of muscles and ligaments below the rib, and with side-bending of the vertebrae to which they are attached; (rotation if the traction is low enough with less pressure on shoulder).

    To make this technic effective for mid and upper dorsals, anchor the patient’s elbow against operator’s abdomen or by means of left hand, while applying tension to spinal muscles with right hand.  Or, with operator’s left hand on patient’s left shoulder, patient’s arm thrown over operator’s arm, the arm may be carried up toward patient’s face until tension is produced on pectoral and intercostal muscles, with similar traction.  The student should explore the various effects of different positions and tensions of patient’s arm and shoulder on vertebral and rib movements, while applying traction to muscles and ribs.

    To make this technic effective in upper dorsal and lower cervical areas, carry the patient’s head slightly back with left hand, and press his shoulder slightly back and down with right wrist while right hand is applied to muscles of upper dorsal or lower cervical areas.

    For the neck, however, this technic is best applied with patient supine, operator’s left hand on patient’s forehead, rotating it in direction opposite to traction, his right hand passing across the neck to the left side of the spinous processes, applied to the muscles of the neck.  The effect of traction in this position, beside the tension on the muscles, is to cause complicated movement of the cervical vertebrae.  The traction alone would cause the head to roll to the right with approximation of articular surfaces on right, extension on left.  The rotation by the forehead alone would cause first rotation of the atlas-axis joint then extension of the right articular surfaces and approximation of those on the left.  The combination of the two causes extreme rotation of the atlas on the axis to the left, rotation side-bending of the lower cervical vertebrae to the right, and extreme lateral  motion of the vertebrae over which tension is applied (a sort of combination of many motions) to the left.  The picture varies with the kind and degree of tension and rotation applied.  The student should try to form a moving picture of the actual movements of the different parts of the neck.

    There is an endless variety of ways in which the pressure technic and the traction technic may be applied to the relaxation of muscles, according to the convenience and stature of the operator and the conditions in the patient’s body.