Principles of Osteopathy
4th Edition
Dain L. Tasker, D. O.

CHAPTER XIV - Subluxations

    Definition. - The word subluxation was so new, to the general medical profession, that much ridicule was heaped upon the osteopaths because they advocated such a ridiculous theory as that "all diseases are caused by dislocation of bone." We are not so sure but that this ridicule was, to a large extent, well merited by the osteopaths.  The loose way in which the words luxation, dislocation and subluxation are used in some of our literature shows that they do not always cover a definite idea in the mind of the writer.  They can not be used interchangeably.  The word subluxation should be used to denote a definite condition.  Subluxation is defined as a partial dislocation in which the normal relations of the articulating surfaces are but slightly changed.

    Da Costa describes subluxation of the shoulder, also of the head of the radius.  For the latter condition he has collected eight different explanations.  We have not been able to find the term used in reference to any other articulations.  The osteopath uses the term to define certain inequalities in the arrangement of vertebrae and ribs, sacroiliac and other articulations.  Perhaps we hear the term used in connection with the atlas more than with any other bone.

    Characteristics of Subluxation. - Subluxations allow considerable movement in the articulation, but to the trained hand there are evidences of malposition.  Pain is developed when the complete normal  movement is attempted by the operator.  Digital pressure around the joint causes deep pain.  There is usually a history of accident, exposure or visceral disorder.

    Primary or Secondary Lesions. - From experience we know the frequency of very evident malpositions of vertebrae, commonly spoken of as subluxations, and as being true or primary lesions causing disordered function in the area of peripheral distribution of the nerves from that segment of the spinal cord.

    The Characteristic Structure of Joints. - In order to get at a true understanding of what subluxation is, we must make a careful study of the structures which form a joint and their vital manifestations.  The bones of the skeleton are bound together by ligaments and muscles.  The opposing surfaces of bones forming movable joints are covered with cartilage.  The muscles execute and the ligaments, or soft parts around a joint, limit the motions of the articulation.  All movable articulations have their bony parts maintained in their normal relations either by the form of the bones and cartilages attached to them or by the equal tension of all the controlling muscles.  Enarthrodial joints have freest movements and yet are the least dependent on muscles for retention of their normal position.  Air pressure and the form of the bones are responsible for the integrity of these joints.  These joints are less frequently subluxated than those possessing more limited motion.  Arthrodial joints depend upon the equal tension of their governing muscles to keep the opposed surfaces in their proper relations.  Coordination of the muscular tension is usually so perfect that the joint surfaces are perfectly opposed to each other.  The disturbance of this nicely balanced muscular tension results in the drawing of one or both bony surfaces away from their true relations; not entirely, but sufficiently to make it possible for the physician's fingers to note the change.

    The Atlas. - The atlas is placed not only first in the vertebral column, but also first in importance to the osteopath on account of the great possibilities for slight displacement between it and the occiput.  All the conditions are present which make a very movable joint and close at hand are important nerves and blood vessels whose slightest maladjustment causes instant disturbance at the very fountains of fife.  No physical examination is considered complete without noting accurately the position of the atlas.  There being no spinous process all reckoning must be made from the transverse processes.

    Occipito-Atlantal Articulation. - According to Gray's Anatomy: "The movements permitted in this joint are flexion and extension, which give rise to the ordinary forward and backward nodding of the head, besides slight lateral motion to one or the other side.  The Recti Laterales are mainly concerned in the slight lateral movement.  According to Cruveilhier there is a slight motion of rotation in the joint." According to Gerrish:

    "Some lateral gilding is also allowed, by which the outer edge of the condyle on the one side is depressed and on the other is elevated in relation to its socket.  Or the movement may be obliquely lateral, one condyle advancing slightly at the same time that it is depressed toward the median line, while the opposite condyle takes the reverse position.  This is the position of greatest stability, and is assumed in the most easy and natural attitudes.  Lateral movements are restrained by the check ligaments and tile lateral parts of the capsules.  No true rotation is allowed."

    The capsular ligaments are very loose, hence the strength of the joint lies in the anterior, posterior and lateral ligaments.  There is no cartilaginous disk between the atlas and occiput, hence motion is limited only by the ligaments named.

    If one should judge of the prevalence of dislocations of the atlas by the number of times such a condition is mentioned in osteopathic literature, we would draw the conclusion that everyone's atlas is dislocated.  The term dislocation is a strong one and ought not to be used in connection with the atlas.  Its dislocation would cause death instantly.  Subluxation is the proper term to use.  Subluxations can be readily diagnosed; the fact that they exist can not be doubted; all positions between the normal relations and complete dislocation are possible.  The complete dislocation of this bone from the occiput means death; intermediate positions, subluxations, mean irritation of nerves direct and both direct and indirect disturbances of circulation; direct disturbance by pressure exerted on arteries and veins, indirect disturbance by excitation of vasomotor nerves.

    The Causes of Subluxations. - It is difficult to account for these subluxations of the atlas without bringing in the contraction of muscles.  This seems to us to be the most prevalent cause of misplacement of the atlas.  Even though we recognize the numberless jars, twists and strains of this articulation, still the resultant bad effects are maintained by the unequal contraction of opposing groups of muscles which is brought on by these accidents.  Take, for instance, the various twists of the atlas found by osteopathic methods of physical diagnosis.  Gray says: "The Recti Laterales are mainly concerned in the slight lateral movements." This is the movement concerned in a lateral subluxation.  The position in which we usually find the atlas is an oblique one, having the right transverse process hugging the angle of the jaw while the left is too close to the mastoid process.  Gerrish describes this position as the "obliquely lateral," a normal movement.  We also consider it normal if it possesses the ability to slip back into a position having similar relations on both sides.  It is a subluxation when it can not get out of that position without assistance.  If there is free movement in the occipito-atlantal articulation, every change of the position of the head will change the relations in this joint.  Our bodies are constructed so that when the bones, forming a joint, are moved to their fullest extent, pressure is usually exerted on the soft tissues around the joint.  This is normal, but when these normal relations are retained too long and the bones do not resume their easy resting position the condition becomes abnormal; it is then a subluxated joint.

    There is no articulation in the body whose bony parts are abnormally related when the extreme movement in the joint is made. (We will except the sacroiliac articulation, because it is not ordinarily considered a movable joint.) The subluxation consists in the relation of the bony surfaces in a position other than that which they should hold during relaxation or equal tension of all the muscles.  The normal position of the transverse processes of the atlas is pictured in Fig. 102.  The subluxations are pictured in Fig. 103.

    Normal Relations of the Atlas. - The normal relations of the atlas are illustrated by photographs of the skull and first vertebra in Fig. 104.  Fig. 105 shows an oblique side view.  In Fig. 106 the atlas is slightly twisted, so that the right transverse process is posterior.  This rear view shows the distance between the left mastoid and left transverse process increased.  The right transverse process is prominent.  The same relations viewed from below are shown in Fig. 107.  The right transverse process is slightly posterior to the mastoid.

    Abnormal Positions of the Atlas. - Fig. 108 and Fig. 109 show side and lateral views of a twisted atlas.  In preparing these bones for photographing, it has been borne in mind that the articulating surfaces must be kept in close apposition.  The relations illustrated are normal to the articulation, but abnormal when retained in these positions after relaxation of opposing muscles.

    The Effect of Muscle Contraction. - If, as Cruveilhier says, there is a slight rotation in this joint and osteopathic practice proves Cruveilhier's statement true, then what muscle could by its persistent contraction cause this rotation to be maintained?  The Rectus Capitis Anticus Minor is so placed as to cause this movement.  It arises from the anterior surface of the lateral mass and root of transverse process of the atlas, and passes obliquely upward and inward.  It is inserted into the basilar process of the occipital bone.  This muscle has as its external relation the superior cervical ganglion of the sympathetic, and as a contracted muscle is thicker than an uncontracted one, pressure may be exerted on this ganglion which may also be irritated by the transverse process of the atlas being pulled toward it, thereby lessening its normal space in more than one direction.

    The reflexes originated by this irritation of the superior cervical ganglion, or its connections, may initiate changes in the caliber of the blood vessels of the brain, eyes or any other circulatory area under control of the ganglion.

    The Effect on Circulation. - The influence exerted directly on circulation by the subluxation of the atlas is probably most active where the vertebral arteries pass through the foramena in the transverse processes.  It might be argued against this view that nature has not failed to provide a certain amount of elasticity in the artery and surrounding structures to meet just such a condition.  Nature has certainly done this, but not with the idea in view that any such exaggerated condition is to be maintained for any great length of time.

    Effect on Superior Cervical Ganglion. - Subluxations of the atlas are found in connection with a great number of disturbed areas, but the condition in each is the same.  For example, there is no difference between a hyperaemia in the nasal, pharyngeal or laryngeal mucosa and a congestion of the retina, except in location.  We must not view the phenomena of retinitis as especially different from those of laryngitis.  If we should do so, we fix our attention on symptoms and see a picture which conceals causes.  When the superior cervical ganglion has its function of vaso-constriction inhibited by continued irritation, the work of maintaining vascular tone is passed along to peripherally placed ganglia.  If the eyes are strained by overwork, the resistance of their nerves is decreased.  This, added to the weakened vaso-constrictor action of the superior cervical ganglia, allows congestion, a retinitis.  Wearing high collars weakens the resistance of nerve endings in the skin of the neck.  This, added to low power in the ganglionic station, leads to congestion in the pharynx or larynx.  Treatment must be applied to the structures around the ganglion, and peripheral nerve power increased by gradually exposing the skin to the atmosphere.

    Atlo-axial Articulation. - The articulation between the atlas and axis is the most intricate in the whole spinal column, consisting of four distinct joints.  Rotation takes place between these bones, but this motion is limited by the check ligaments.  Dislocation of the odontoid process causes instant death by pressure on the lower part of the medulla oblongata.  The articulations between the articular processes of these bones are arthrodial.  The articulation between the odontoid process of the axis and anterior arch of the atlas holds the bones firmly together.  Most of the rotation in the cervical region is in this joint.  Although there is so much movement allowed by these articulations, we seldom find the axis subluxated.

    Unequal Development. - Deviation of the spine of the axis from the median line is a frequent condition, but in the majority of cases is its normal relation on account of uneven development.

    Caries. - Hilton describes cases of disease of the articulation between the atlas and axis, showing how destruction of the transverse ligaments allows the head to tip. forward, thereby causing the odontoid process to impale the medulla.

    Dislocation. - We may safely say that dislocation of the atlo-axial articulations is probably the rarest condition we will ever meet.  Various degrees of rotation may be met with which are in the nature of subluxations due to muscular contractions.

    Spontaneous Reduction. - Since the above paragraph was written, an article in the Medical Record, March 3, 1900, has come under my observation.  The article is entitled "Spinal Fracture-Paraplegia." The author, Dr. Robert Abbe, exhibits a radiograph illustrating a case of dislocation of the neck.  The dislocation is between the articular processes of the atlas and axis.  The most interesting feature of the case is the spontaneous reduction of the dislocation while the patient was asleep.  The author thinks that the relaxation of sleep and the restlessness of the patient combined to reduce it.

    Cervical Vertebrae. - The remaining cervical vertebrae are occasionally forced from their proper relations by violence.  Quite a number of cases are on record which show how great the disturbance is in such conditions.  Those cases recorded in medical literature are complete dislocations, and hence can not be classed with subluxations such as are met with in osteopathic practice.  In order for complete dislocation to take place, i. e., so that the articular processes are both locked, the intervertebral disks would have to be torn and would probably bring great pressure on the cord.

    All grades of subluxation are found between cervical vertebrae.  Where the violence has not been sufficient to cause locking of the articular processes, it has exaggerated the normal movement sufficiently to injure the ligaments or muscles, which therefore maintain the subluxated position.

    Disproportion Between Cause and Effect. - We cannot estimate the extent of the systemic effects of a lesion in the spine.  What might appear to us to be a very' slight lesion might be the cause of a very profound nervous disorder.  The position of the lesion is the chief means of estimating results.

    Example. - To illustrate this point, we may mention the case of Mr. Norton Russell.  A lesion of the sixth cervical vertebra was found.  The vertebra was slightly twisted.  Mr. Russell had not slept during one hundred nights and days without the use of sulphonol or morphine.  The first osteopathic treatment applied to the sixth cervical vertebra made it difficult for him to keep awake until he reached his home and then he fell into a profound sleep.  There was a history of severe accident.  Muscular contraction was very evident.

    Unequal Development of Spinous Processes in Cervical Vertebrae. - Fig. 110 illustrates the appearance of the posterior surfaces of the cervical vertebrae, second to the seventh, when all the vertebrae are in normal position, i. e., articular surfaces evenly opposed to each other.  The changing character of the spinous processes is readily noted.  Nearly all of these processes are unevenly developed, showing that palpation of these prominent points can not help being unsatisfactory.  The tubercles on the back and outer surfaces of the inferior articular processes present a much more uniform development and they can be easily palpated after one has become accustomed to the feel of the cervical muscles.  Fig.  III shows the third cervical subluxated to the right.  The tubercle on the left inferior articular process is made more prominent.  The muscles over this point will be found contracted.

    Palpation of Dorsal Spinous Processes. - When the spines of the dorsal vertebrae are palpated, the trained fingers may find individual spines which are not in line with those above and below, or that the spacings between the spines are not equal.  The deviations from the normal are indicative of changed relations between the vertebrae.

    Normal Dorsal Movements. - The normal movements in the dorsal region are flexion, extension and rotation.  The lesions in this region correspond with these movements.

    False Lesions. - We must guard against being misled by the deviations which we find, especially lateral ones.  Fig. 112 illustrates a decided lateral inclination of the third dorsal spinous process.  Such a deflection from the median line would be noted by the unskilled touch of a layman.  This deflection has no diagnostic significance, unless there is pronounced sensitiveness around it, and then it is the hyperaesthesia and not the osseous formation that must be noted.  A very skillful osteopathic diagnostician might be misled by this lesion.  There does not appear to be any way to protect against a wrong interpretation in a case like this except the experience of the physician in weighing all the evidence.

    Lateral Subluxation. - Fig. 113 illustrates a genuine lateral subluxation of a dorsal vertebra.  The arrangement of the Rotatores Spinae account for such a lesion as this.  They arise from the upper surfaces of the transverse processes and insert into the laminae above.  The subluxated vertebra in this group is the fifth.  The digitation of the Rotatores Spinae between the right transverse process of the sixth and lamina of the fifth must contract in order to produce this condition.  This digitation may respond to a severe visceral reflex and cause a stibluxation of this character.  Direct violence may cause it, also a cutaneous reflex initiated by temperature change in the atmosphere.

    Muscular Contraction. - Muscles contract as a result of excessive straining or wrenching, or exposure to cold and of reflex irritation.  If opposing muscles under all conditions of temperature, mechanical and reflex irritation would continue to exert equal influence on a joint, then nothing but a complete dislocation would be possible.  A movable joint is enclosed in a synovial membrane which facilitates the rapid return to a normal position.  All the mechanical conditions in and around a joint are conducive to the quick return to normal.  It is the vital and not the mechanical principle which keeps up a condition of maladjustment.  No intermediate position is possible, there being no unevenness of surface to become locked, unless we take into consideration the vital activity as manifested in a contracted muscle.

    Comparison of Effects of Muscular Contraction. - J. E. Stuart, D. O., has made an apt comparison between the pull of the muscles of the back on the individual vertebrae and the well recognized insufficiencies of the ocular muscles.  All physicians recognize the serious effects of long continued insufficiency of an ocular muscle, but few, indeed, have given any thought to the possibility of a similar condition affecting structures less movable, or less sensitive, than the eyeball.  The relation of a vertebra with its fellows is of great importance to the delicate nervous tissue which it surrounds.  It is not necessary for a vertebra to press upon the spinal cord, or nerve fibers coming from or going to it, in order to produce irritation.  There is a nerve strain in connection with these lesions which is not the result of direct pressure but of the efforts of the central nervous system to balance and coordinate the contraction of the muscles pulling on the vertebra.  It is not necessary for divergent or convergent squint to be so marked that the expression of the eyes is instantly noted by all observers before any symptoms of eye strain are felt by the patient.  Neither is it necessary for a vertebra to be dislocated in order to create a disturbance.  It is conceivable that a completely dislocated vertebra might, after a time, cause as little irritation as an eyeball which is so divergent that no effort is made to use binocular vision.  The body becomes accommodated to the change.

    Separation of Spinous Processes. - Figs. 114 and 115 give two views of the fifth, sixth and seventh vertebrae, illustrating the separation of the spines, as in extreme flexion.  Note that the superior articular facets are uncovered by the movement.  The vertebrae assume this position in kyphosis.  We frequently find that there is a gap between two spines while the spacing above and below is quite even.  Either the space, directly above or that below this gap is lessened.  Fig. 116 shows the spine of the fifth, sixth and seventh dorsal vertebrae in the position of extreme extension.  The spines crowd hard upon each other.  These illustrations all show normal positions, but they are the ones which our fingers discover as lesions of the vertebrae.

    Approximation of Spinous Processes. - When two spines are closely approximated, as in Fig. 116, there is necessarily a widening of the next space above or below, depending upon which vertebra is affected.  The contracted space will usually be sensitive to digital pressure.  There is a contractured condition of the muscles causing this extreme movement of extension., This contracture disturbs the rhythm of nerve: Impulses from that section of the spinal cord in closest relation with the disturbed vertebra.  There is lack of coordination of movement in the affected joints.  When several vertebrae are tightly bound together a straight, non-flexible spinal column is the result.  The muscles are tightly contracted and more or less sensitive to digital pressure.

    Primary Subluxations. - These conditions, as here illustrated, are what osteopaths usually designate as spinal subluxations which are causative factors in disease.  They are sources of irritation to the spinal nerves in direct central relation with them, and these nerves convey disturbed or arythmical impulses to the viscera and blood vessels, thus causing the various perversions of function which are recognized as symptoms of disease.

    Secondary Subluxations. - These lesions must also be recognized as structural changes resulting from excessive irritation to the peripheral end of sensory nerves, either those ending in skin and subject to the temperature changes or those ending in the visceral muscosa and subject to irritation from the presence of food of an indigestible character, products of fermentation, etc.  We must recognize the fact that sensory nerves are subject to excessive stimulation in casts of gluttony or masturbation.  Both of these bad habits may result from the stimulation of a spinal lesion, but experience with humanity teaches the physician that mankind in general delights in gratifying the senses.  We do not wish to place spinal lesions at the bottom of man's moral weaknesses.

    Limited Area for Lateral Subluxations. - Lateral subluxations may exist as low as the tenth dorsal spine.  The articular processes of the eleventh and twelfth dorsal take on the character of the lumbar, hence rotation is practically impossible There is a digitation of the Rotatores Spinae between the eleventh and twelfth dorsal vertebrae.

    Lower Dorsal Vertebrae. - Figs. 117 and 118 give a posterior and lateral view of the five lower dorsal vertebrae.  The changing characteristics of the spinous processes of these vertebrae should be carefully noted, so that the student may not be misled as to the significance of that which his palpation may discover.  The eleventh dorsal spine takes a horizontal direction, and in some cases this makes either a very narrow space between it and the tenth or a very wide space between it and the twelfth.

    Dorso-Lumbar Articulation. - The junction of the dorsal and lumbar regions is very flexible.  A large portion of flexion and extension of the spinal column is made in this articulation.  The most common condition noticeable in the lower dorsal region is increased prominence of the spines, and incipient kyphosis.  This condition frequently affects the junction of the dorsal and lumbar regions.

    Kyphosis - Lower Dorsal. - A slight kyphosis in the lower dorsal region is indicative of loss of tone in the extensor muscles governing the articular surfaces.  The spines are separated farther than normal and the inferior articulating surfaces are partly uncovered by the superior ones.  This weakened condition of the back may be brought on by injury, or reflexes from the bowels or kidneys.  Continual vibration of the spinal column, as in cases of street car men, weaken the back and then functional disturbances of the kidneys are noted.

    Lumbar Region. - Figs. 119 and 120 illustrate the lateral and posterior appearance of the normal lumbar vertebrae.  The spinous processes are easily palpated in this region.  Their development varies enormously in different individuals.  The formation of the articular processes prevents any rotation, hence we do not find any lateral subluxations in this region.  The position of individual vertebrae is rarely affected.  "Breaks," that is, separations of the spines, are sometimes noted, but not often.  Violence is the chief cause of these separations.  The muscles in this region are thick and powerful, hence their influence is not exerted so much on individual vertebrae as upon the whole series of vertebrae.  Therefore we find curves instead of subluxations in this region.  Exaggeration of the normal movements is responsible for kyphosis, lordosis or scoliosis.  Extreme weariness, as a result of maintaining a sitting or standing position, leads the individual to shift the weight of the body so as to take some advantage of the ligaments which limit a movement.  The strength and flexibility of the lumbar region is frequently a very good criterion of the patient's bodily vigor.  It is easier to affect this portion of the spinal column, by leverage movements, than any other region.

    Examination of the Ribs. - The position of the ribs is always noted by the osteopathic physician.  It is noted, in medical textbooks on diagnosis, that the general conformation of the thorax is indicative, to a variable degree, of either the past medical history of the individual or is evidence of the present existence of predisposition to certain diseases.  A full, round, nonflexible chest denotes asthma or emphysema; flat chest denotes tendency to tuberculosis, etc.  These statements are generalizations based on long observation, and are usually very near the truth.  The respiratory movements should be noted, whether full and free, compared with the capacity of the thorax.  The osteopathic physician goes farther than these excellent generalizations in his diagnosis.  The relation and position of each individual rib are extremely important.  The condition of the whole thorax and its contents is dependent on the relations of, the bones which form it.  With this idea in mind, a careful examination of each rib is made.

    The ribs are, normally, quite movable. Their spinal articulations are so arranged that an easy rise and fall of the shaft of the rib is permitted.  The rise and fall is the result of rotation of the rib on an axis passing through the costo-central and costo-transverse articulations.

    Costo-central Articulations. - The costo-central articulations of the first, tenth, eleventh and twelfth ribs have no interarticular ligament.  The movement of the heads of these ribs is limited by the capsular ligaments.  The heads of all the other ribs are held in place by interarticular ligaments attached to ridges on the heads of the ribs and to the intervertebral disks.

    Costo-transverse Articulations. - The tubercles of the ribs articulate with the transverse processes of the vertebrae forming arthrodial joints.  The superior costo-transverse ligaments prevent the dropping down of the costo-transverse articulation.  There is very limited gliding movement in this articulation.  As before stated, the movement in the costo-central and costo-transverse articulations is rotary.  The shaft of the rib lies obliquely downward, therefore the rotation of the rib during inspiration turns the anterior extremity upward and outward.  The axis of the rotation through the costo-vertebral articulations is obliquely downward, therefore the lateral position of the shaft of the rib is elevated during inspiration and the lower border is turned outward.

    Coordination. - Fig. 121 illustrates the normal obliquity of the fifth and sixth ribs.  When the contraction of all the muscles of respiration is properly coordinated, the intercostal spaces are all equal in width.  The respiratory rhythm should be equal in all parts of the thorax.

    Incoordination. - When through some nervous reflex inspiration is made difficult, the inspiratory muscles expand the thorax to its fullest extent and retain the expansion.  Then the diameters of the thorax are increased.  This position of extreme inspiration is typical of the asthmatic chest.  There may be lack of coordination of the muscles in any intercostal space.  This incoordination may be manifested by too much contraction or relaxation.  The result is a change in the normal width of an intercostal space.

    Nervous Control of Respiration. - Respiration is carried on by a complicated mechanism.  Its chief center of normal control is in the medulla, but subsidiary centers, in linear series, exist in the spinal cord.  Each spinal nerve which innervates intercostal muscles, or other muscles of inspiration, arises from a subsidiary respiratory center.  One of these subsidiary centers may become too active or passive as a result of local irritation, due to circulatory changes.  The muscles governed by this disturbed center will not act harmoniously, hence the rhythmical movement of all the ribs is interfered with.

    We have noted that spinal muscles contract unevenly as a result of direct spinal injury, exposure of the skin over them to cold, or from visceral reflexes.  The respiratory muscles are subjected to the same conditions.  A lateral subluxation in the dorsal region carries its articulated rib with it. Palpation will discover their changed relations.  A kyphosis in the dorsal region causes the ribs to rotate upwards, thus increasing the diameters of the thorax.  Lordosis in this region has the opposite effect.

    Costal Subluxations. - Figs. 122 and 123 illustrate the changes in spacing of the ribs due to incoordination of muscular contraction.  These positions of the ribs are spoken of as costal subluxation.  In Fig. 122 the upper rib is rotated downward as a result of a contraction of the intercostal muscles in the space below it, or the relaxation of those above it.  Palpation elicits
sensitiveness at the lower border of this fifth rib.  The sensitiveness is usually found where there is compression due to the dropping of the rib and the contraction of the muscles.  This rib might have become displaced as a result of violence, or the patient might have been exposed to cold air while sweaty, or some disease of another part of tile body might have caused sufficient weakness to allow this rib to drop as a result of pressure occasioned by the position in bed or otherwise.

    Whatever the cause of these subluxations, they certainly become sources of great irritation to the nervous system.  Sometimes the body becomes accommodated to these subluxations, but the fact that cases of asthma have been cured after years of suffering, by reducing these malpositions, is prima facie evidence that accommodation is something that can not always be depended on.  The heads of the second to ninth ribs cannot be dislocated without rupture of the interarticular ligaments.  Considerable change in the position of the shaft of the rib occasions very little change in the position of the head of the rib.

    First Rib. - The first rib does not move in the same manner as those below.  The attachment of the scalenus anticus keeps the shaft always raised.  No matter how flat the remainder of the thorax may be, the first rib stands out prominently.  The chief change in its position is due to the contraction of the scalenus anticus, therefore it needs to be depressed rather than elevated.

    Tenth Rib. - The head of the tenth rib is articulated with the body of the tenth vertebra; there is no interarticular ligament.  This allows freer movement.  Its anterior extremity is insecurely articulated to the cartilage of the ninth rib.  This connection is frequently broken, thus making an added floating rib.

    Eleventh and Twelfth Ribs. - The eleventh and twelfth ribs are very loosely articulated to the vertebrae.  They have no costo-transverse ligaments, hence depend on the action of muscles to hold them in place.  They are frequently found rotated upward or downward.

    We have endeavored to show that the normal movements of the ribs, as a whole, may become very abnormal when made individually, or out of rhythm with each other.  The depressions or elevations of individual ribs have not dislocated their articulations; they have merely carried and retained them in positions out of harmony with the remainder of the ribs.  They have become discordant members of a harmonious body, and unless made to cooperate for the general welfare, they will rapidly make other members inharmonious.

    Effect of Position of Vertebrae on Position of Ribs. - Lack of symmetry in the dorsal vertebrae causes a change in the position of the ribs.  Both conditions can be corrected by reduction of the vertebral subluxations.

    The Clavicles. - The clavicles may be elevated or depressed by muscular contraction.  Their depression affects the vessels crossing the first rib and from the upper extremity.  The subclavius is responsible for the depression of the clavicle.

    Summary. - Every individual has his or her particular development.  When examining patients this must be taken into consideration.  All subluxations must be judged according to the condition of the reflexes along the nerve tracts which they might influence.

    A subluxation is evidence of unequal activity of opposing muscles, caused by twist, strain, fall, thermal change or reflex irritation from viscera.  It is an evidence of vital activity unevenly manifested.  The mechanical condition which we call a lesion, may be only evidence of a lesion which lies in the excessively active muscle or at some other point in close nervous connection.
A subluxation may be called a primary lesion when it results from accident.  It is secondary when due to reflex action.  It is not always possible to determine whether a lesion is primary or secondary, but in general it is best to reduce them wherever found, if any disturbance can be traced to them.

    In rare instances one treatment has been found sufficient to reduce a subluxation.  The fact that the majority of cases must be treated two or three months proves that they are not easily kept reduced.