Studies in the Osteopathic
Basic Principles: Volume
Louisa Burns, M.S., D.O., D.Sc.O.
THE EXPERIMENTAL DEMONSTRATION OF THE OSTEOPATHIC CENTERS:
THE CRANIAL STRUCTURES.
Normal Innervation of the Cranial Vessels.
blood vessels of the cranial structures receive their nerve impulses from
a very complex arrangement of nerve centers in the floor of the fourth
ventricle and the acqueduct of Sylvius, and in the spinal cord of the upper
thoracic region. These centers are not described very clearly in
the ordinary text books of physiology, and therefore a brief and simplified
description of their relations will be given here for the sake of making
the significance of the experimental work intelligible to those whose study
of the relations of the cranial sympathetics has not been unusually thorough.
It is not possible, within the limits of this volume, to give an exhaustive
description of these relations.
description of the manner in which the vessels of the nasal membrane receive
their vaso-motor impulses will serve as an illustration of the innervation
of the vessels of all the cranial structures.
coordinating centers for the vascular innervation of these membranes, as
for all other structures of the body which receive vaso-motor nerves, are
affected by afferent impulses from the structures whose circulation they
control, by impulses from other centers in structural and functional relationship
with these, and by impulses from certain ganglia grouped around the base
of the brain.
sensory impulses carried over the olfactory nerve are of value chiefly
because of the impulses which they send to the cerebral cortex, and the
information thus given in consciousness. There is reason to believe
that olfactory impulses do initiate some efferent impulses to the nasal
mucous membrane, but these are not yet well understood. Their further
discussion is of no immediate interest in this connection.
fifth cranial nerve is the nerve of common sensation to the cranial structures.
Since the nerves of common sensation are the ones which most efficiently
carry impulses aroused by external changes to the vaso-motor centers, the
fifth is the nerve chiefly concerned in the afferent side of the path of
the nasal vaso-motor reflexes. Stimulation of the sensory endings
of the nasal branch of the ophthalmic division of the fifth nerve by irritating
gases or dust reaching the nasal mucous membrane causes an increased secretion
of the nasal mucous glands and a congestion of the nasal membranes.
The pathway traversed by the impulses concerned in this familiar reaction
is shown in the following diagram.
A—Ophthalmic division of fifth nerve.
B—Nasal branch of ophthalmic.
C—Superior maxillary division of fifth nerve.
D—Mandibular division of fifth nerve.
E,E—Nucleus of insertion of fifth.
G—Vaso-motor center (location not exactly known).
H—Lateral horn of cord of second or third thoracic segment.
I—First or second thoracic sympathetic ganglion.
J—White ramus communicans.
K—Superior cervical ganglion.
L—Gray fibers from K to various branches of fifth nerve.
N—Sensory axons from M to E.
O—Nucleus of origin of seventh nerve.
P—Nucleus of origin of sixth nerve.
S—Nucleus of twelfth nerve.
T—Sensory ganglion cell.
The sensory impulses arising from the stimulation of the nerve endings
of the fifth are carried by way of the Gasserian ganglion, M, into the
nucleus of insertion of the fifth, E, E, in the floor of the fourth ventricle.
The nucleus of insertion of the fifth is a group of nerve cells which form
a long, slender mass which underlies the whole length of the fourth ventricle.
The entering axons of the fifth nerve, N, divide in a T-shaped manner,
as do the axons of the spinal ganglia upon their entrance into the cord
Collaterals from these axons form synapses with nearly or quite all of
the nuclei of the other cranial nerves, and with the cells of the various
centers in the medulla and pons.
of the axons from this nucleus carry impulses by way of the fillet, F,
to the optic thalamus, whence they are sent to the cerebral cortex, where
consciousness is affected; other axons carry impulses to the vaso-motor
center, G, in the lower triangle of the floor of the fourth ventricle.
The exact location of the vaso-motor center is not known, but since the
axons and collaterals from the nucleus of the fifth enter practically all
areas of the gray matter at all levels within the bounds which are
known to include the vaso-motor center, the relations are unquestionably
the vaso-motor center impulses are carried by axons which pass downward
through the lateral ground bundles of the spinal cord to the upper thoracic
region. Here the axons which carry the impulses concerned in the
regulation of the size of the vessels of the nasal mucous membrane plunge
into the gray matter of the cord, and terminate by forming synapses with
the neurons of the lateral horns in the second and third thoracic segment,
H. The neurons of the lateral horns send their axons by way of the
white rami communicantes, J, into the sympathetic system. The axons
in which we are now interested do not enter into relations with the sympathetic
ganglion cells until the superior cervical ganglion, K, is reached.
The axons of the cells of the lateral horns which carry impulses for the
control of the cranial sympathetics retain their medullary sheaths through
the upper dorsal and cervical region until they reach the superior cervical
ganglion. Here they break into fine fibrillae, which form networks
around the bodies of the sympathetic neurons. The axons of the sympathetic
neurons are not medullated. Those concerned in nasal vaso-motor impulses
pass to the nasal branch of the ophthalmic division of the fifth nerve,
and with it reach the vessels of the membranes whose sensory nerves were
seems from the appearance of slides prepared in these laboratories that
several cells of the sympathetic ganglia may be affected by one axon from
the white ramus, and that more than one axon from the white ramus may affect
a single sympathetic cell. This structural relation renders possible
the very diffuse manner in which visceral reflexes are produced.
must be plainly understood that the sympathetic system is not in any sense
a complete system, but that it is merely a way station for the transmission
and diffusion of impulses from the viscero-motor centers in the spinal
cord, medulla, pons, and mid-brain. It must be understood, also,
that none of these centers has any volition at all, but that every efferent
nerve impulse is the inevitable result of the structural and functional
relationships of the centers concerned in the reaction.
Cells from the Thoracic Sympathetic Ganglia of the Cat.
1, 2, 3, 5 and 6 were stained by different haematoxylin methods.
4 and 7 were stained after the method of Nissl.
A—Axon from the sympathetic cell, arising from an axon hillock.
B—Axon from white ramus, breaking into fibrillae around the sympathetic
C—Remnant of the medullary sheath.
dendrites of the sympathetic neurons and the fibrillae from the axons from
the white ramus make a perfect rete mirabile. It is probably because
of this marvelous complexity and the extreme tenuity of the fibrillae that
the relationships here illustrated have not been described before.
the first series of experiments, the electrodes were placed upon the nasal
mucous membrane of animals under anesthesia. The muscles near the
third thoracic vertebrae were at once strongly contracted. The latent
period was very short in all reactions involving the cranial structures.
The cervical muscles were somewhat contracted in more than half of the
animals subjected to the tests.
electrodes were then placed upon the conjunctivae. The muscles near
the second vertebra were then contracted. There were also slight
and inconstant contractions of the cervical muscles.
electrodes were placed upon the eyeball. The muscular contractions
were sometimes noted near the second thoracic vertebra, but the reaction
was not constant. The cervical muscles were scarcely contracted at
electrodes were placed upon the outer surface of the eyelids. The
facial muscles were contracted very quickly and forcibly, but no contraction
of the muscles of the upper dorsal region was noted.
electrodes were placed upon the tongue, the inner surface of the cheeks,
and the roof of the mouth. The facial muscles were quickly contracted,
and reflex muscular contractions were noted near the third thoracic spine.
electrodes were placed upon the tonsils. The reflex muscular contractions
appeared near the third and fourth thoracic spines.
electrodes were placed within the pharynx. Muscular contractions
appeared near the third thoracic spine.
throat was exposed to view, and the electrodes placed upon the vocal cords.
The cervical muscles were very strongly contracted, as were also the spinal
muscles of the fourth and fifth thoracic segments. The first and
second intercostals were also strongly contracted.
trachea was opened and the electrodes placed upon its inner surface.
The scalene and the sterno-cleido-mastoids were very strongly contracted.
The first and second intercostals , and nearly all of the inter-scapular
muscles were also contracted.
electrodes were placed upon the thyroid glands, and the reflex muscular
contractions appeared near the second and third thoracic spines.
The contractions initiated by the stimulation of the thyroids were not
very strong, but were constant. The deeper cervical muscles were
always involved in the reflex action caused by the stimulation of the thyroids.
skull was opened and the electrodes placed upon various portions of the
meninges. The facial muscles were contracted in all instances, and
the cervical muscles were often contracted also. The upper dorsal
muscles were not often contracted unless the brain itself were stimulated.
In this case, the effects of the stimulation depended upon the area of
the cerebral cortex affected.
Superior Cervical Ganglion.
superior cervical ganglion was exposed to view, and the electrodes placed
upon it. The pupils became greatly dilated, the conjunctivae because
lighter in color, and the mucous membranes of the nose and throat were
also lightened. The superior root of the superior cervical ganglion
was cut. The direct stimulation of the ganglion produced no effects.
The sympathetic chain was cut below the superior cervical ganglion.
Direct stimulation of the ganglion produced the same effects as before.
Therefore the pressure of abnormally contracted cervical muscles upon the
superior cervical ganglion may exert an evil effect upon the cranial structures
which receive their innervation by way of these ganglia.
After Section of the Sympathetic.
section of the sympathetic chain, stimulation of the cranial structures
did not produce any effect upon their blood vessels, except such as might
be referred to the direct influence of the electricity upon the vessels’
walls. Therefore, the impulses concerned in this reflex action pass
upward through the cervical sympathetic chain.
The Gasserion Ganglion.
Gasserion ganglion was exposed to view. The ganglion was stimulated
directly. The upper thoracic muscles were very strongly contracted,
and the blood vessels in the area of the distribution of the fifth nerve
were immediately and strongly contracted. Some of the sympathetic
fibers are carried by way of the fifth nerve. In order to exclude
the effect of the direct stimulation of these fibers, the fifth nerve was
cut, and the central end was stimulated by the electrodes. The muscles
of the upper thoracic region were contracted, as before. The vessels
in the area of distribution of the fifth nerve were contracted after latent
period of a minute or so.
Extirpation of the Gasserion Ganglion.
Gasserion ganglion could be extirpated in some animals without perceptible
injury to the sympathetic fibers from the superior cervical ganglion.
This must have been due to some peculiarity of distribution of the sympathetic
fibers. The operation was considered to be successful when the direct
stimulation of the upper thoracic sympathetic cord produced effects upon
the pupils and the blood vessels of the mucous membranes of cranial structures.
In some animals, the sympathetic fibers are so closely connected with the
fifth cranial nerve that the extirpation of the ganglion prevents all passage
of nerve impulses from the cervical or upper thoracic ganglia to the cranial
tests made upon the animals in whom the extirpation of the Gasserion ganglion
was possible without injury to the sympathetic fibers will be considered
at this time.
this operation, the stimulation of the cranial structures did not produce
any perceptible effects upon the vessels of the tissues stimulated, or
their neighbors, except such effects as might be attributed to the direct
effects of the electricity upon the vessel walls. The stimulation
of the fifth nerve did not produce any contraction of the muscles in the
upper thoracic region after this operation.
stimulation of the central end of the injured nerve caused strong muscular
contractions in the upper thoracic region, and also constriction of the
vessels in the area of distribution of the fifth. Direct stimulation
of the superior cervical ganglion produced effects identical with those
produced before the mutilation.
spinal cord was cut above and below the superior cervical ganglion.
This cut was made from behind, and the sympathetic chain was uninjured.
The effects noted after both operations were the same, and can be described
stimulation of any cranial structure failed to cause reflex contraction
of the muscles in the upper dorsal or the cervical region.
of the cranial structures did not produce any vascular changes except those
which might be referred to the direct effects of the electricity upon the
stimulation of the superior ganglion produced the effects noted before
the cervical portion of the spinal cord is an essential element of the
reflex arc by way of which sensory impulses from the cranial structures
are able to effect the condition of the upper dorsal muscles, and also
in the path by which these impulses are able to affect the size of the
blood vessels of the cranial structures themselves.
Cranial Somato-Visceral Reflexes.
relations demonstrated in the series of experiments just described were
held to be suggestive of certain possibilities of somato-visceral reflexes.
stimulation of the tissues near the second thoracic spine was followed
by a contraction of the blood vessels of the cranial mucous membranes and
the conjunctivae, by a dilatation of the pupils, and an increased secretion
of saliva. These effects were practically invariable.
artificial lesion affecting the tissues near the second thoracic vertebra
produced a dilatation of the blood vessels which was most marked in the
conjunctivae, but which affected the other cranial membranes to some extent.
of the tissues near the third thoracic vertebra was followed by a constriction
of the vessels of the nasal mucous membranes and the pharynx. The
effects upon the conjunctivae were less conspicuous.
artificial lesion affecting this vertebra caused a slight rather general
congestion of the cranial membranes.
of the cervical tissues did not produce any effects upon the cranial structures
unless the stimulation was so pronounced that the cervical sympathetic
chain or ganglia were directly affected.
of the muscles in the cervical region affected the sympathetic structures
very easily, hence, the existence of abnormally contracted muscles in the
cervical region is a menace to the normal activity of the cranial sympathetics.
artificial lesion affecting the cervical vertebrae caused contractions
of the cervical muscles rather readily. In the lower spinal areas
the artificial lesion affected the spinal muscles only slightly, within
the time occupied by our experiments, but the cervical muscles become contracted
within a few minutes after the artificial lesion was produced. The
latent period for all cervical and cranial structures is comparatively
superior cervical ganglion was subjected to mechanical stimulation by the
manipulation of the tissues over it. In animals, this maneuver was
followed by dilatation of the pupils, and by a contraction of the cranial
vessels, which was soon followed, if the stimulation was continued, by
a dilatation which was rather persistent.
Extirpation of the Gasserion Ganglion.
the extirpation of the Gasserion ganglion without the injury of the sympathetic
nerves, the mechanical stimulation of the tissues near the second and third
thoracic vertebrae caused the same vaso-constriction and pupilo-dilation
as was observed in the animal before mutilation.
the destruction of the cervical portion of the sympathetic chain, and after
the extirpaton of the Gasserion ganglion in most animals, the mechanical
stimulation of the tissues in the upper dorsal region did not produce any
Destruction of the Cervical Cord.
the destruction of the cervical portion of the spinal cord, stimulating
movements in the upper dorsal region produced the same effects upon the
blood vessels and the pupils as did the same movements before mutilation.
In some instances, the reactions were increased after the destruction of
the cord, as was to be expected. It was not possible to make quantitative
tests of these reactions, under the conditions of our experiments.
Experiments Upon Human Subjects.
series of experiments were performed upon human beings. Irritation
of the skin over the back of the neck caused temporary dilatation of the
pupils. The most conspicuous results were secured when the irritation
(a brush was used) was applied to the skin over the seventh cervical to
the second thoracic spines.
stimulation of the tissues near the second and third thoracic spines caused
dilatation of the pupils and contraction of the vessels of the cranial
or the maintenance of an artificial lesion, caused dilatation of the vessels
of the nasal mucous membranes and of the conjunctivae. The eyeball
was also somewhat congested The pupils were dilated in this case
superior cervical ganglion is subject to direct stimulation in most persons.
The fingers were firmly placed over the ganglion, and the deep vibrating
movements given. In some cases, the electrodes were firmly pressed
over the ganglia, one on either side. The effects of this procedure
were very pronounced. The blood vessels of the conjunctivae, the
mucous membranes of the nose and mouth, were all first lightened, then,
if the stimulation were continued, reddened and congested with blood of
rather a purple color, as if it were flowing more slowly than its custom.
The flow of saliva was increased. The pupils attained very great size,
if the stimulation were continued for a few minutes The upper lids
were drawn upward and the eyeball protrudes The tears were increased,
and often overflowed. All of these effects are due to the stimulation
of the superior cervical ganglion.
the effects are so pronounced when this stimulation is given for only a
few minutes, the effects upon the cranial vascular system of abnormally
contracted muscles pressing upon the sympathetic ganglia can certainly
not be disregarded with impunity. It is extremely difficult to secure
adequate inhibition of the anterior cervical structures, because of the
propinquity of the pulsating carotid arteries.
of the tissues over the cervical vertebrae in persons, as in animals, caused
contractions of the cervical muscles, but no effects upon the cranial structures
were discerned, except such as could be referred to the effects of the
pressure of these contracted muscles upon the sympathetic trunk and ganglia.
no case were we able to affect mental conditions by manipulations planned
to stimulate or inhibit the action of vaso-motors to the brain. Changes
produced in the size of the vessels of the cranial structures sometimes
caused headache and discomfort, but not ever any consciousness of sleepiness
or of increased mental vigor, such as accompanied the various manipulations
affecting blood pressure which were made upon the abdominal viscera
These experiments do not deny the existence of vaso-motor nerves to the
brain, but they do not demonstrate them.
far as our present knowledge goes, we must consider that the circulation
through the brain is most easily affected through changes in the general
blood pressure and that this is most easily controlled by affecting the
size of the blood vessels, in the splanchnic area, and in some cases, by
affecting the efficiency of the heart beat.
Centers for the Cranial Structures.
superficial or osteopathic centers for the control of the cranial structures
may thus be located as follows:
the eyes, the level of the first and second thoracic vertebrae. Lesions
of the vertebrae or muscles higher and lower than these may affect the
eye tissues also. The eyes may be affected by direct manipulation
of the superior cervical ganglion, and lesions affecting this ganglion
may affect any of those structures of the orbit which receive innervation
by way of the sympathetic system.
the nasal mucous membrane, the second and third thoracic vertebrae.
Lesions higher and lower than these, and lesions affecting the superior
cervical ganglion may also affect the circulation of the nasal membranes.
The relation of upper thoracic and cervical lesions with adenoids is very
the pharyngeal structures, the third and fourth thoracic vertebrae.
Here, as in the other cases, lesions of the vertebrae above and below those
mentioned may affect these structures. Lesions affecting the middle
and superior cervical ganglia directly may exert an evil influence upon
the circulation and metabolism of these structures.
centers for the trachea and larynx are not to be at the level of the third
thoracic. Lesions affecting the nerves of this and neighboring spinal
segments, as well as lesions affecting the middle and superior cervical
ganglia, may affect the thyroids through their nerves Other lesions
affecting the thyroids by direct impingement upon their vascular and lymphatic
drainage were not subjected to experiment.
centers for the trachea and larynx are not to be distinguished from those
for the upper lobes of the lungs.
Olfactory Motor Paths, in Morat’s Physiology of the Nervous System, p.
643, Edition of 1906.
Nerves and Reflexes, in any text book of Physiology.