Blood Circulation In The Brain example essay topic

Throughout the history of the human race, mankind has been locked in a constant struggle with its own limitations and imperfections. Bound by norms and social stratification, civilization has molded itself into a conformist society. The same society that looks upon radical medicinal practices and alternative ways of thinking with disdain. One medical custom met with great opposition from most cultures is that of trepanation. Elaborated in this text will be the history, truths and falsehoods, popular views, and clinical documentation of the practice of trepanation and reasons behind the use of this type of surgery.

Trepanation is one of the earliest surgical operations known. There is ample evidence to show that it was practiced by primitive man in prehistoric times. The scraping of a hole in the cranium by ancient man was probably carried out with the intention of relieving pains in the head or curing epilepsy, and at the same time providing an exit for an evil spirit to escape from. Recently, archaeologists have discovered a 7,000-year-old burial site at Ensisheim, in the French region of Alsace.

At this site is the earliest evidence of trepanation. The burial contains the well-preserved skeleton of a man, who died at roughly 50 years of age, as well as an arrowhead and an adze typically dated to 5100-4900 BC, a date corroborated by a radiocarbon sample from the bone. Two trepanations had been carried out on this man. One toward the front of the skull, measuring 2.6 by 2.4 inches, had healed completely. The second had only partially healed, probably because of its enormous size (3.7 by 3.6 inches). The larger trepanation appears to have been produced by intersecting incisions, and the smaller one may have been made in the same way.

The long-ter healing evident from the bone indicates the operations were successful. (Walker, 2-8) In the western hemisphere, trepanning was practiced at an early period by the ancient Incas of Peru, who performed it with great dexterity. Scientists have found that 5 to 6 percent of the ancient skulls excavated in Peru show that trepanning was resorted to for therapeutic reasons. The Incas preferred square openings, and the operation is still practiced by native medicine men among some tribes in South America in much the same manner as it was carried out in ancient times. The patient's head was held tightly between the surgeon's knees; the patient reclining and the doctor sitting. An incision was then made in the scalp and a section of bone, approximately an inch square, removed from the skull.

The instrument employed was a sharp piece of flint or hardened copper with a rough edge, which was used by rubbing the edge backwards and forwards along the bone. (Thompson 23) In western civilization we find that trepanning was practiced freely in the time of Hippocrates (c. 400 B.C. ). The instruments employed by the early Greek surgeons varied, and included the trerbra, or drill, chiefly used for making a circle of holes around the depressed bone, which was operated by a thong around the centre or on a cross beam.

For the same purpose, the trepan on, operated by a bow, like a drill, was sometimes employed to make the perforations, and the interspace's between each hole were broken up by the scalpel so that the roundel of bone could be removed. (Haeger, 14-15) The first innovation in what we now know as the modern trepan was introduced towards the end of the 16th century, when in 1575 Matthias Barvatio invented a mechanical instrument which was operated by a cog wheel turned by the hand. This was connected with another wheel, which when rotated actuated a circular saw which cut into the bone. This device ultimately turned out to be too heavy and clumsy to be used skillfully.

(Haeger, 16) Towards the close of the 19th century, there was a return to some of the earlier types of instruments. In 1889, the trepan was introduced as a mechanical rotatory trephine. Mechanical drill-stocks also came to be used with drills or trephines. Several years later, the trepan was introduced with a crutch shaped handle, but since that time no marked change appears to have been made in this instrument employed on the cranium. (Haeger, 17) In today's context, most trepanations are carried out for the sake of attaining a higher level of consciousness. For the most part, a Dutch medical scientist named Bart Huges can be cited for the resurgence of trepanation in modern society.

In 1962, the physiology underlying consciousness was brought to light by Huges. The breakthrough in understanding concerned the fact that the level of consciousness is dependent on the total quantity of blood in the capillaries of the brain; when that quantity is increased, the result is accelerated brain metabolism and therefore an enhanced level of neurological functioning. However, three basic factors - the force of gravity, the relative density of blood compared to water, and the imprisonment of the brain in a case of bone - cause a problem for man in his upright position. This problem is a shortage of blood in the brain capillaries which necessitates permanent repression from function of most of the brain, symptoms of which appear throughout human behavior. The solution is to increase the brain's blood volume. This can be brought about by trepanation; an adult's 'brain-blood floor' can be raised permanently to the level it was at during childhood and youth when cranial sutures had not permanently closed yet.

(Hughes, 42-50) Methods of enhancing consciousness are as old as man. What is new is the explanation of how they work; i.e. the description of the physiological mechanism behind the experience. The question as to whether the brain pulsates when the skull is completely closed and fully ossified, as it is known to do in open skulls, is one of the fundamental problems in the study of cerebral blood circulation. This question is of prime importance because those who have been trepanned state that the pulsing of blood to the brain from the circulatory system is critical for attaining a higher consciousness. (Sokol off, 66) Brain pulsation is clearly visible in the infant child. The soft tissue on the top of the head known as the fontanel rises and falls with the beating heart.

This expansion and contraction on the heartbeat does not threaten the infant's good health. However, within the first few months of life this tissue hardens into skull bone. The visual evidence that the heart beat still reaches into the brain vanishes before our eyes. Still the infant's good health is unaffected. But does the heart pulsation (also known as cardiac rhythm) continue to exist inside the skull even if it can't be seen This is an important question scientists have posed. The first views on the causes of cerebral pulsations may be found in the works of Galen (131-201 A.D.) whose observations were based on observations in animals.

He suggested that brain pulsations were directly related to the respiratory rhythm, and were due to seepage of air into the cerebral ventricles through the cribriform plate. He also considered brain pulsations to be possible because of the existence of a vacuum between the cerebrum and the dura. (Michell, 53) Later, Vesalius (1600) wrote on the movements of the brain in new-born babies and adults who had sustained cranial injuries and on animals whose skulls were opened in vivisection studies. The brain movements were ascribed to the pulsations of the arterial branches of the dura. It was thus thought that these brain movements were due to its swelling following the increased blood content following each pulse wave.

(Michell, 57-58) After the discovery of the cerebrospinal fluid in which the brain substance bathes, however, the problem of the existence or absence of brain pulsations was approached in an entirely different light (Contugno, 1864; Magen die, 1825). It then became clear that the space between the surface of the brain and the dura mater which formerly was thought to be filled with compressible air, was actually filled by the incompressible cerebrospinal fluid. A review of the work of different investigators published during the past century shows that some of them were able to solve the problem as to whether brain pulsations exist in the closed skull cavity, as long ago assumed by Galen. Such a process was possible only when one assumed the existence in the brain of a space filled with air, allowing for alterations of the cerebral volume. When the cerebrospinal fluid was discovered, it was recognized that the cranial cavity was completely filled and the point of view that cerebral pulsations in the hermetically closed skull were not possible also appeared in the literature. Because of this finding, Muller (1839) and Bourguignon (1839) were of the opinion that cerebral pulsations did not exist.

An attempt to support this view experimentally was made by Pele htan. Into the skull of a dog he inserted a glass tube and recognized that the cranial cavity was completely filled with fluid and cerebral pulsations would not be possible. (Hughes, 78-85) Brain pulsation, or intracranial pulse pressure, has largely been ignored as a subject for investigation by the medical establishment in Western Europe and America. The primary investigators in modern times have been Russian. Most important amongst them is B.N. Klosovskii, who is otherwise recognized internationally for his methods of studying blood circulation in the brain. In the mid 1950's he developed methods of tissue staining that allowed the arteries and the veins of the brain to be clearly distinguishable.

The vascular bed was then for the first time clearly mapped. His main work, Blood Circulation In The Brain, was translated from the Russian in 1963 and published under an agreement with U.S. Public Health Service. The last several chapters of Klosovskii's text deal with the ideas of brain pulsation and his belief that there is no pulsing in a closed skull. (Colton) Klosovskii, however, is not without critics. Other Russian investigators dispute his findings.

In their work Hemodynamics of Cerebral Circulation, also published by the U.S. Public Health Service, Moskalenko and Naumenko take up the case against Klosovskii. Using impedance electroplethysmography, an entirely different method than Klosovskii's direct observation through a "transparent window", they find that there is a "pulse wave" in the hermetically sealed skull. Their measurements indicate that this pulse is in the order of 1-2 mm of water. Cardiac rhythm, pulse pressure, or pulsation is normally measured in mm. of Mercury (mm. Hg) not mm. of water. The difference in order of magnitude here is one to thirteen.

(Thirteen mm of water equals one mm of mercury). They conclude, "in the hermetical cavity of the cranium, the pulse wave is transmitted indirectly from the arterial system into the veins and in doing so bypasses the capillary bed". The "pulse wave" that they had measured in the closed skull is in no way equivalent to the presence of "pulse pressure" that Klosovskii observes on the cerebral surface in the open skull. (Michell, 97-98) In a 1960 review titled Soviet Investigations in the Field of the Vascular Supply of the Brain, the noted American brain physiologist, Ernst Simonson, disputes those investigators using impedance plethysmography. He says, "The viewpoints are in need of confirmation, as it is rather difficult to imagine that alterations of intracerebral pressure of only 1 to 2 mm. water column can lead to blood being expressed from the cerebral veins, no matter how thin-walled these may be". (Hughes, 111-119) Many people in today's society consider trepanation to be a kind of blood- letting.

An operation done in the hopes it will make a person better, but rather winds up hurting the sick worse. For thousands of years, a select few in society have stood up for practices they believed would better their life. In the case of trepanation, maybe those who open their skull should not be looked down upon as crazy. These select few, in their own eyes, have seen all the proof they need to consider this operation as a viable way of making their life more fulfilled. Reviewing the information that has been published, as well as the testing of new theories by scientists and physicians, will hopefully answer the question of whether or not the human race is being retained from achieving a higher state of being. However, even if it is proven that a hermetically-closed skull does in fact pulse, many would agree it would not stop the act of trepanation.

People who decide to carry out the process of opening their skull would still stand with the notion that increasing one's brain blood volume is the only way to increase a persons state of being.