This article is taken from book by prof. George Abbott, published in 1914 in USA. We would like to present it to the bigger group of readers, especially when it is very difficult to be found anywhere. Therefore we took this opportunity to present an interesting matter as seen back in 1914. Still some parts of this article are valid, and hydrotherapy as presented here is being used in spa treatment.
THE CIRCULATION- REFLEX EFFECT
AND PRACTICE OF HYDROTHERAPY FOR STUDENTS AND PRACTITIONERS OF MEDICINE
Prof. George Knapp Abbott
During health, there are vasomotor influences constantly playing upon the arteries in all parts of the body. These influences hold the vessels in “tone,” i.e. control the rhythmic oscillations in caliber, so that blood pressure is maintained. These influences seem to emanate from a vasomotor center which is located in the medulla oblongata in the floor of the fourth ventricle. “Irritation of this center causes contraction of all the arteries and, in consequence, increase in arterial blood pressure.” “Paralysis of the center causes relaxation and dilatation of all the arteries, with enormous reduction in blood pressure. Under normal conditions, the vasomotor center is in a state of moderate tonic excitation.” While this center exercises a controlling influence over all, it is not the only vasomotor center. “Centers for the vascular nerves, both vasomotor and vasodilator, are distributed throughout the entire spinal axis.” “They can be excited reflexly, although they are subordinated to the dominating centers in the medulla oblongata.” “It is obvious that such a mechanism as that described… is susceptible of reflex stimulation through sensory nerves, and according to our general knowledge, we should suppose that a tonic center of this kind may have its tonicity increased (excitation) or decreased (inhibition).” It is to the reflex stimulation of these centers that we now wish to turn our attention, for through this channel, hydrotherapy produces some of its most important effects.
Maximilian Schuller, in experimenting on trephined rabbits, observed that severing single nerve trunks on one side of the animal produced a distinct (though transient) dilatation of the pial vessels on the corresponding side, thus proving that the blood vessels of the piamater are held in steady tone by continuous excitation from the cutaneous sensory nerves. This result was observed only on the side of the severed nerve so that it could not have been due to shock or pain.
“Naumann has demonstrated clearly that the effects of external irritants upon the circulation within the body are really reflex. He separated the head of a frog from the body, leaving them connected by the medulla oblongata only. He next severed one leg, after preventing loss of blood by typing the vessels, so as to leave it connected with the body by the sciatic nerve. Now he applied thermal, chemical, and electric stimuli to the foot of the partially severed leg, while he observed, under the microscope, the mesentery of the frog. Shortly after gentle irritation of the peripheral endings of the sciatic nerve in the foot, the circulation in the vascular network of the lungs and mesentery was accelerated, and resumed the former condition slowly after the withdrawal of the irritant. A more severe irritation produced retardation of the flow, and even stasis occurred, as if the heart had become temporarily paralyzed. A strong irritant produced dilatation; a feeble one, constriction of the vessels. The effect of these peripheral irritations on the heart was also noted. A strong irritation of the skin weakened its circulation; a feeble irritant strengthened it. As there was no possible vascular or nerve channel from the part irritated to the part thus visibly affected, the conclusion is inevitable that the effect is entirely reflex. Hot water acted precisely as other irritants.” These experiments also prove that there are two reflex means by which the circulation may be influenced, viz., reflex stimulation of the vasomotors, producing changes in vascular caliber, and reflex stimulation of the heart muscle itself. Another point, brought out by the experiments of Rohrig, is that when intense cutaneous irritants produce considerable slowing of the heart beat, they also increase its force. This is the effect of a prolonged cold application, whether general, as with the Brand bath, or local, as with the ice bag to the precordia.
Reflex Areas: The fact of reflex stimulation being established, we may next consider the location (topography) of the various reflex areas. While the brain, heart, and other viscera may be reflexly influenced by stimuli applied to many different cutaneous areas, some even very remote from these organs, the maximum effects are produced by stimulation of certain very definite and well recognized areas. In general, it may be said that the skin over an organ is reflexly related with that organ. In most cases, it is not difficult to trace the nerve connection.
“In general, the skin overlying an organ is reflexly associated with it, which is the reason why applications of electricity over an organ usually influence it, and not altogether because the current is passed through the organ. When these areas are studied comparatively, it is noted that they are practically the same as those regions pointed out as showing reflex pain, which would suggest a nervous path from the organ to the skin and from the skin to the organ, the termination of which are in the same visceral and cutaneous fields.” So definite and circumscribed are some of these areas that B.G.A. Moynihan has frequently observed, in cases of duodenal ulcer, a small hypersensitive spot in the skin covering the abdomen, directly over the ulcerated area. It is no larger that a six-pence and he attaches much value to this phenomenon in differentiating ulcer.”
It must not, however, be supposed that the reflex path from the viscera to the skin over which pain is referred is the same path as that utilized in therapeutics for reflex effects upon the internal organs. Nor are the skin areas to which pain referred always the same areas that should be utilized to influence reflexly the organ in which the cause of pain is located. For example, in the case of liver and gall-bladder disease, there is frequently a pain in the region of the right shoulder, or shoulder blade, but it is not to this region that applications are made to relieve distress due to hepatic or biliary affections.
The various cutaneous areas to which the pain or tenderness, due to visceral disease, is referred, are spoken of as the dermatones of Head. They are in some cases of considerable service in diagnosis and are sometimes serviceable as a guide in the placing of therapeutic applications. They cannot, however, be implicitly relied upon for either purposes. Relative to this unreliability Abrams says, “The elicitation of the dermatomes of Head is a tedious method of examination and not always accompanied by satisfactory results for the reason that a great amount of experience is necessary. Alsberg in the examination of two hundred women (with gynecological affections) found cutaneous areas of hyperalgesia in only seventeen, ten of whom were hysterical. Therefore, he could attribute no diagnostic import to the zones in question beyond commenting on the fact that hysterical stigmata must be excluded before the zone of hyperalgesia could be regarded as trustworthy.” Diagnosis and therapeutics based on para-spinal tenderness must, therefore, be of a highly imaginative character and especially so when approached from the standpoint of a prejudgement as to the causes of disease and consequently its treatment.
The law that the skin over an organ is reflexly related with that organ may be regarded as an amplication of Hilton’s law: The principal nerve to a joint not only supplies the articular surfaces but also some of the main muscles that move that joint and the skin over these muscles. In the case of the viscera, however, the deeper part of the reflex arc consists of a sympathetic neuron.
The Reflex Arc: The reflex arc consists of several parts. In general, the following is the path taken by a stimulus arising in the skin from a thermic application and traced as a reflex stimulus to the organ underlying the skin surface treated. From the skin it is conveyed by a sensory (temperature) nerve along a nerve trunk to the posterior root of the spinal nerve; entering the posterior root ganglion, where the fiber is seen to be the distal axon of a T-cell, it passes on through the central axon of the T-cell into the posterior side of the spinal cord. On entering the cord, the fiber immediately divides into an ascending and descending branch, both located in the posterior white columns and which give off collaterals to the gray matter. The ones we are concerned with end in tufts about the cells of the column of Clark. According to Starling, the vasomotor center in the medulla corresponds in position to the column of Clark which is doubtless that which represents the vasomotor center throughout the rest of the cord. From these cells, axons pass either into Gower’s tract and end in the cerebellum, or pass out with the anterior root, and through the white ramus to the ganglion of the lateral sympathetic chain. Passing directly through this or up or down through an adjacent ganglion, they end in a peripheral ganglion from which the viscus is supplied.
“The fibers of the white ramus which pass through the ganglion and go to the periphery are known as the splanchnic efferent fibers, and constitute the secretory fibers of the splanchnic glands and the motor fibers of the muscular tissue of the splanchnic blood vessels and viscera.”
By studying carefully the above reflex path, it will be noted that a stimulus may affect (be shunted to) cells either above or below the level at which it enters the spinal cord. And again, the fiber that conveys the reflex stimulus to the viscera may pass up or down in the gangliated cord. This fact is of importance in explaining why cutaneous nerves are connected reflexly with splanchnic nerve trunks not arising in the same segment of the cord.
Of the many reflex paths, we may pick out two as serving to quite fully illustrate reflex effects. First, let us study the reflex arc concerned in the effect produced by an ice bag applied to the precordial region. And second, the arc concerned in the reflex between the skin of the epigastrium and the stomach.
The Heart: Before considering the reflex arc, we should understand that the heart is supplied with nerves from two sources. First, through the vagus nerve (fibers of accessory part of the spinal accessory nerve) with inhibitory fibers, i.e., fibers which when stimulated slow the heart beat and increase its force. Second, by accelerator fibers, which when stimulated increase the rapidity of the heart beat through the cardiac sympathetic nerves from the inferior cervical ganglion. The accelerator fibers emerge from the spinal cord in the anterior roots of the second, third, and fourth thoracic spinal nerves and, according to some authors, are found also in the first and fifth thoracic nerves. From these spinal nerves, they pass to the corresponding sympathetic ganglia of the lateral chain through the white rami communicantes, and thence upward to the inferior cervical ganglion.
The ice bag applied to the precordia covers the skin supplied by the second, third, fourth, and fifth thoracic nerves. The stimulus (of a depressing nature), produced by the cold application, is carried to the spinal cord by the nerve fibers of these thoracic nerves which end in the same segments in which the accelerator fibers of the heart arise. The reflex stimulus produced by the afferent impulse (sensation of cold) upon the cells in the column of Clark is conveyed outward by the axons of these cells through the anterior roots and by way of the white rami reaches the sympathetic ganglia through which they pass to the inferior cervical ganglion, and thence by the inferior (sympathetic) cardiac nerve, to the deep cardiac plexus and the heart muscle. The accelerator mechanism being depressed, the heart beats slower and with greater force from the proportionately greater action of the inhibitory nerves.
An ice bag over the heart produces its action by depressing the accelerator (sympathetic) nerves and not by stimulating the vagus, as has been claimed by some; which latter, it will be seen, would be impossible, since the prolonged cold of the ice bag exerts a depressing and not a stimulating effect, which latter must be the case were slowing produced through the vagus.
The Stomach: The skin over the pit of the stomach is supplied by the seventh and eighth intercostals nerves. The great splanchnic nerve is formed by branches from the thoracic ganglia between the fifth or sixth and the ninth or tenth. It terminates in the semilunar ganglion of the solar plexus. From the solar plexus, (celiac part) fibers accompany the blood vessels to the stomach.
“The nerves supplying the abdominal muscles and the skin are derived from the lower intercostals nerves and intimately connected with the sympathetic nerves supplying the abdominal viscera through the lower thoracic ganglia from which the splanchnic nerves are derived.”
These reflex arcs may be traced out in the case of other organs and areas. While an application to the skin over an organ gives a maximum effect, applications to even very distant areas may be quite effective. For example, hot applications to the feet do not, under ordinary conditions, influence reflexly the circulation of the brain. But under the conditions of vasomotor instability, such as that following a sunstroke, a hot foot bath may cause congestion of the brain (personal observation).
Special Reflex Areas: The following are the principal reflex areas employed in hydrotherapy
areas of the face, scalp, and back of the neck are reflexly related
with the brain
More practically stated, the circulation, secretory, and muscular activities of the viscera may be influenced reflexly by applications as follows:
by applications to the head, face, back of neck, hands and feet
In the large majority of cases, the ventral areas give stronger reflex effects than the dorsal areas. This is doubtless for the reason that, with a ventral area, the effect is concentrated upon a single organ, while in the case of a dorsal area, limited to the region of the spine itself, the effect would be spread out over several organs, or possibly, the viscera of both the chest and abdomen. “If an ice bag is placed in contact with the whole length of the spine, the same effect on the heart and lungs is produced as that which is desired on the intestines, and the whole process is negatived, whereas, if limited anteriorly to the sixth segment, the effect is localized on the abdominal viscera.”
Definition of Reflex: A reflex effect is then an indirect effect produced through nerve connection. An application to one part of the body which influences, through nerve connection, another part of the body is said to exert a reflex effect. Abrams gives the following definition: “A reflex refers to involuntary production of activity in a part brought about by conduction of a stimulus along an afferent (sensory) nerve to the motor cells in the cord or medulla. This stimulus is converted into an impulse by the motor cells, which impulse is then conducted to a part by means of an efferent (motor) nerve.”
Classes of Reflex Effects: Having established the fact of reflex action and traced out some of the reflex arcs, let us now consider the nature of the various reflex effects. We have already noted that there are three kinds of fibers which make up the splanchnic efferents: viz., the secretory, viscero-motor, and vasomotor. These are also the chief functions of the various viscera and by these, metabolism itself and all other functions are controlled. “By applying heat or cold or other stimuli to the segment of the skin whose endings are in a segment in which arise visceromotor, vasomotor, or other acitivities, we can reflexly affect the organ supplied by these tracts. That this can be done has been shown by the researches of Brown-Sequard and others, … chiefly through the vasomotors. The change may be observed by heat and cold, impact of water, hand pressure (steady or alternated), electricity, mechanical stimulation or, other means, yet the underlying principle remains the same. The application of these physical forms of therapy must be made more and more accurately to get the best effect.”
There are two general classes of effects produced by these applications. They may be designated as pressor and depressor, as stimulant and calmative, or excitant and sedative. Because the pressor, stimulant, or excitant effects are usually mild and tend to restore to a normal tone, they are frequently designated as tonic.
Special Reflex Effects: In general, the reflex effect of an application is the same as its direct effect upon the skin. That it may be somewhat less quantitatively would be a natural result. The following is a comparison of the direct and reflex effects of prolonged cold.
effects upon the part to which the application is applied
The reflex effect obtains as long as the application is in place and for a variable length of time after its removal. The duration and intensity of reflex effects depend upon the duration and intensity of the application. The vasoconstrictor effects of prolonged cold may not be very marked in health, but in the case of a congested organ, an ice bag applied to the reflex area produces an astonishing result.
Special Reflex Effects of Prolonged Cold: A long (continuous) local application of cold causes contraction of the muscles and decreases the vital activities of the surface treated and the internal part reflexly related therewith.
over the trunk of an artery causes contraction of the artery and its
distal branches. For example, ice bag applied over the carotid arteries
decrease the blood going to the brain and head generally. Such an application
is called a proximal application, since it is located between the heart
and the part supplied
Special Reflex Effects of Short Cold: Short cold applications to a reflex area produce tonic and stimulating effects in the deep part by virtue of the reaction which soon follows. The same is true of alternating applications of heat and cold:
applications to the face and head stimulate mental activity
Reflex Effects of Hot Applications:
much prolonged hot application to a reflex area produces passive dilatation
of the blood vessels of the related organ