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.
[Illustration:
A. Cortico Spinal nerve. B. Spino Ganglionic nerve. C. Ganglio
Ganglionic nerve. D. Ganglio Peripheric nerve. E. Blood Vessel Wall.
Parker
Fig. 32. Schematic representation of nerve pathway from brain to
periphery by way of sympathetic.
]
_Liver_: Fourth thoracic nerves (especially the right) to gangliated
cord, via great splanchnic nerve to coeliac plexus, by hepatic plexus
to interior of liver. The hepatic plexus gives off the cystic plexus
which controls the gall-bladder.