scholarly journals On the decussation of fibres at the junction of the medulla spinalis with the medulla oblongata

1843 ◽  
Vol 4 ◽  
pp. 71-72
Keyword(s):  
Medulla Oblongata ◽  
Royal Society ◽  
The Body ◽  
Cerebral Lesion ◽  
Common Occurrence ◽  
Satisfactory Explanation ◽  
Actual Structure ◽  
Spinal Marrow ◽  
Motor Columns ◽  
The Brain

The author first alludes to what usually happens in affections of the brain, namely, that the loss of voluntary power and of sensation, manifest themselves in the opposite side of the body to that in which the cerebral lesion exists, a fact which has been attempted to be explained by the crossing of the fibres at the junction of the medulla oblongata with the anterior or motor columns of the medulla spinalis ; but such a structure, he observes, affords no explanation of the loss of sensation. The author then, referring to the communication of Sir Charles Bell to the Royal Society, in the year 1835, describing a decussation connected with the posterior columns, or columns of sensation, mentions that the accuracy of these dissections was doubted by Mr. Mayo and other eminent anatomists. The author proceeds to state that the symptoms of cerebral lesion do not always take place on the opposite side of the body to that in which the lesion of the brain exists, but that they occur sometimes on the same side; that the loss of power and of sensation, although confined to the same side, may exist in either the upper or the lower extremity; but that both are not necessarily implicated; and that, in fact, cases occur where there are marked deviations from what may be considered the more common occurrence. Having observed such cases, and not being aware of any satisfactory explanation, the author examined with care the continuation upwards of the anterior and posterior columns of the spinal marrow into the medulla oblongata and found that the decussation at the upper part of the spinal marrow belonged in part to the columns for motion, and in part to the columns for sensation; and farther, that the decussation is only partial with respect to either of these columns; thus elucidating hy the observation of the actual structure what before appeared very unsatisfactory in pathology, and anomalous in disease. The paper is illustrated by drawings made from the dissections of the author.

scholarly journals V. A letter on a canal in the medulla spinalis of some quadrupeds

1809 ◽  
Vol 99 ◽  
pp. 146-147
Keyword(s):  
Royal Society ◽  
Human Subject ◽  
Cauda Equina ◽  
The Other ◽  
Small Stream ◽  
Spinal Marrow ◽  
The Brain ◽  
Contrary Direction

Sir, According to your request, I send you an account of the facts I have ascertained, respecting a canal I discovered in the year 1803, in the medulla spinalis of the horse, bullock, sheep, hog, and dog; and should it appear to you deserving of being laid before the Royal Society, I shall feel myself particularly obliged, by having so great an honour conferred upon me. Upon tracing the sixth ventricle of the brain, which corresponds to the fourth in the human subject, to its apparent termination, the calamus scriptorius, I perceived the appearance of a canal, continuing by a direct course into the centre of the spinal marrow. To ascertain with accuracy whether such structure existed throughout its whole length, I made sections of the spinal marrow at different distances from the brain, and found that each divided portion exhibited an orifice with a diameter sufficient to admit a large sized pin; from which a small quantity of transparent colourless fluid issued, like that contained in the ventricles of the brain. The canal is lined by a membrane resembling the tunica arachnoidea, and is situated above the fissure of the medulla, being separated by a medullary layer: it is most easily distinguished where the large nerves are given off in the bend of the neck and sacrum, imperceptibly terminating in the cauda equina. Having satisfactorily ascertained its existence through the whole length of the spinal marrow, my next object was to discover whether it was a continued tube from one extremity to the other: this was most decidedly proved, by dividing the spinal marrow through the middle, and pouring mercury into the orifice where the canal was cut across, it passed in a small stream, with equal facility towards the brain (into which it entered), or in a contrary direction to where the spinal marrow terminates.

scholarly journals A comparative study of the brains in pleuronectidae

1937 ◽  
Vol 122 (828) ◽  
pp. 308-343 ◽  
Keyword(s):  
Comparative Study ◽  
Medulla Oblongata ◽  
Royal Society ◽  
Feeding Habits ◽  
Serial Sections ◽  
Naked Eye ◽  
The Family ◽  
Relationship Of ◽  
The Relationship ◽  
The Brain

Part I. The Medulla Oblongata, And Its Variations Acoording To Diet And Feeding Habits In previous communications to this Society the relationship of the habits of feeding and diet to the form and pattern of the medulla oblongata has been described in the cyprinoids, clupeids, and gadoids (Evans, 1931, 1932, 1935). This research takes up a similar study of the brain of the Pleuronectidae. The expense has been borne by a grant from the Royal Society for which the author tenders his grateful thanks. It has seemed to be desirable to extend the observations to the fore- and mid-brain, as in some members of the family these present a very marked development. In order to elucidate some of the problems that arise I have also studied the brain of the eel, and some interesting conclusions have resulted. We find, as a result of examination by the naked eye and of serial sections, that we can divide the following species into four groups as follows: I. The sole, Solea vulgaris .

scholarly journals XIV. Notes of researches on the intimate structure of the brain.—Second Series

1862 ◽  
Vol 11 ◽  
pp. 359-366
Keyword(s):  
Medulla Oblongata ◽  
Royal Society ◽  
Posterior Median ◽  
The Brain

In consequence of the frequent interruptions to which I am ne­cessarily exposed in the course of my anatomical investigations, I beg to communicate to the Royal Society, in the form of notes, some of the results at which I have arrived, with a promise to forward, in a few months, a complete memoir on the same subject, with the necessary illustrations. In my memoir of the “ Medulla Oblongata,” it is shown that the post-pyramidal ganglion, or grey substance of the posterior pyramid, is developed from the posterior grey substance on each side of the posterior median fissure.

On the reflex function of the medulla oblongata and spinalis, or the principle of tone in the muscular system

1837 ◽  
Vol 3 ◽  
pp. 210-210
Keyword(s):  
Nervous System ◽  
Medulla Oblongata ◽  
Hydrocyanic Acid ◽  
Muscular System ◽  
Spinal Marrow ◽  
Reflex Action ◽  
The Will ◽  
The Brain ◽  
Morbid State

The author, after commenting on the opinions of Le Gallois and Cruveilhier relating to the functions of the spinal marrow, adverts to a property or function of the medulla oblongata and spinalis, which he considers as having escaped the notice of these and all other physiologists; namely, that by which an impression made upon the extremities of certain nerves is conveyed to these two portions of the nervous system, and reflected along other nerves to parts different from those which received the impression. He distinguishes muscular actions into three kinds: first, those directly consequent on volition; secondly, those which are involuntary, and dependent on simple irritability; and thirdly, those resulting from the reflex action above described, and which include those of the sphincter muscles, the tonic condition of the muscles in general, the acts of deglutition, of respiration, and many motions, which, under other circumstances, are under the guidance of the will. Volition ceases when the head or brain is removed; yet, as he shows by various experiments, movements may be then excited in the muscles of the limbs and trunk, by irritations applied to the extremities of the nerves which remain in communication with the spinal marrow: but these actions cease as soon as the spinal marrow is destroyed. Hence the author concludes that they are the effect of the reflex Action of the spinal marrow, which exists independently of the brain; and, indeed, exists in each part of the organ independently of every other part. He considers that this reflex function is capable of exaltation by certain agents, such as opium and strychnine, which in frogs produce a tetanic and highly excitable state of muscular irritability. Hence he is led to view the reflex function as the principle of tone in the muscular system. He considers that certain poisons, such as the hydrocyanic acid, act by destroying this particular function. The effects of dentition, of alvine irritation, and of hydrophobia, of sneezing, coughing, vomiting, tenesmus, &c. &c., are adduced as exemplifications of the operation of the same principle when in a morbid state of exaltation.

scholarly journals II. The Croonian Lecture, on some physiological researches, respecting the influence of the brain on the action of the heart, and on the generation of animal heat

1811 ◽  
Vol 101 ◽  
pp. 36-48 ◽  
Keyword(s):  
Blood Vessels ◽  
Royal Society ◽  
Spinal Marrow ◽  
Animal Body ◽  
The Brain

Having had the honour of being appointed, by the President of the Royal Society, to give the Croonian Lecture, I trust that the following facts and observations will be considered as tend­ing sufficiently to promote the objects, for which the Lecture was instituted. They appear to throw some light on the mode, in which the influence of the brain is necessary to the conti­nuance of the action of the heart; and on the effect, which the changes produced on the blood in respiration have on the heat of the animal body. In making experiments on animals to ascertain how far the influence of the brain is necessary to the action of the heart, I found that when an animal was pithed by dividing the spinal marrow in the upper part of the neck, respiration was immediately destroyed, but the heart still continued to contract cir­culating dark-coloured blood, and that in some instances from ten to fifteen minutes elapsed before its action had entirely ceased. I further found that when the head was removed, the divided blood vessels being secured by a ligature, the circulation still continued, apparently unaffected by the entire separation of the brain. These experiments confirmed the observations of Mr. Cruikshank and M. Bichat, that the brain is not directly necessary to the action of the heart, and that when the functions of the brain are destroyed, the circu­lation ceases only in consequence of the suspension of respira­tion. This led me to conclude, that, if respiration was produced artificially, the heart would continue to contract for a still longer period of time after the removal of the brain. The truth of this conclusion was ascertained by the following experiment.

scholarly journals IV. Note on the excitation of the surface of the cerebral hemispheres by induced currents

1874 ◽  
Vol 22 (148-155) ◽  
pp. 368-370 ◽  
Keyword(s):  
Royal Society ◽  
Copper Wire ◽  
The Body ◽  
Secondary Coil ◽  
Living Tissue ◽  
Primary Coil ◽  
Accurate Definition ◽  
Combined Movements ◽  
Induced Currents ◽  
The Brain

In a paper recently communicated to the Royal Society by Dr. Ferrier (Proceedings, No. 151) it is shown that when two ends of copper wire distant from each other not more than a couple of millimetres, and in metallic communication with the terminals of the secondary coil of a Du Bois’s induction-apparatus in action, are applied to certain spots of the surface of either hemisphere, and great intensity is given to the induced currents thereby directed through the living tissue, by previously bringing the secondary coil into such a position that it is very close to the primary coil or even partially covers it, characteristic combined movements of the opposite side of the body are produced. With reference to these effects, it was observed by Dr. Ferrier (1) that excitation of the same spot always produces the same movement in the same animal, (2) that the area of excitability for any given movement (or, as it may be called for shortness, active spot ) is extremely small and admits of very accurate definition, and (3) that in different animals excitations of anatomically corresponding spots produce similar or corresponding results. From these remarkable facts and from others similar to them relating to other parts of the brain to which I do not now advert, it was inferred that, at the surface of the hemispheres, certain “centres” are to be found, of which it is the function to originate combined or even purposive movements.

scholarly journals STROKE

2006 ◽  
Vol 12 (02) ◽  
pp. 114-117
Author(s):  
ASAD ALI ◽  
AHMAD DANYAL ◽  
AFTAB TURABI
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Vascular System ◽  
Medical Problem ◽  
The Body ◽  
Cerebral Lesion ◽  
Cerebral Function ◽  
Careful Monitoring ◽  
Who Criteria ◽  
The Brain

Stroke was defined according to WHO criteria as rapidly developingsymptoms and / or signs of focal and at times global loss of cerebral function with no apparent cause other than thatof vascular disease1. Stroke is grossly divided into either2 1). Thrombotic. 2). Embolic. 3).Hemorrhagic type (Whichmay be either intra cerebral bleed or subarachnoid hemorrhage). The brain, like other organs of the body, requires anadequate vascular system in order to supply it with nutrients and oxygen and to remove metabolic wastes and carbondioxide. Stabilization of medical problem with careful monitoring, and active prevention and timely management ofsecondary complications are of the utmost important for reducing stroke morality rates and avoiding further ischemicbrain injury. For the ischemic cerebral lesion itself, as yet no treatment or combination of treatment has beenestablished to be universally effective3. However, current studies allow for the following 5 potential therapeutic areasto be identified.

scholarly journals II. A note on protagon

1880 ◽  
Vol 30 (200-205) ◽  
pp. 111-113 ◽  
Keyword(s):  
Royal Society ◽  
The Body ◽  
The Brain

In 1879, in conjunction with Dr. Ernst Blankenhorn, I communicated to the Royal Society a paper entitled “On the Existence of Liebreich’s Protagon in the Brain.” In that paper we sought to establish the existence of the body which had been described by Dr. Liebreich, but which had by several writers been considered to be a mixture of lecithin and cerebrin. We gave many analyses of several samples of protagon, and pointed out the constancy in the composition of the body when subjected to repeated crystallization from alcohol. I have since the date of the above paper, in conjunction with Herr Adolf Spiegel and Mr. Leopold Larmuth, continued my examination of protagon, and of certain bodies which accompany it. Our researches, which are not yet in a sufficiently advanced state for publication, have in the fullest degree confirmed the conclusions arrived at by the research of which the results have already been submitted to the Society.

scholarly journals XIV.—Of the Fourth and Sixth Nerves of the Brain;—being the concluding paper on the distinctions of the Nerves of the Encephalon and Spinal Marrow

1839 ◽  
Vol 14 (1) ◽  
pp. 237-241 ◽  
Author(s):  
Charles Bell
Keyword(s):  
Optic Nerve ◽  
Royal Society ◽  
Circular Muscle ◽  
Complex Nature ◽  
Spinal Marrow ◽  
The Subject ◽  
The Brain ◽  
Royal Society Of London

Interesting as theoptical properties of the eye have been to philosophers in every age, there are conditions of this organ which are no less curious, and which have not had their share of attention.In the year 1823, I introduced the subject to the Royal Society of London, nearly in the terms I am now using, but there is much more in the subject than I then conceived, although I see no reason to change the mode of contemplating it.The eight muscles of the eye, and the five nerves, exclusive of the optic nerve, which pass to them, imply the complex nature of the apparatus exterior to the globe, and I fear it is too plain that the subject has not been satisfactorily treated.It is chiefly with respect to the protecting motions of the eye that the difficulty occurs, for I hope the dependence of the proper organ of vision on the voluntary muscles of the eye, has been proved and acknowledged.Permit me to draw the attention of the Society to what appears a very simple piece of anatomy, the circular muscle which closes the eyelids, orbicularis palpebrarum.

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