Lectures

ON THE

Begin) or by a hæmorrhage (as in the case by Mr. S. Solly), or by a tumour, or a pressure by a bone, &c., in man, produces paralysis on the side where it exists, in the spinal cord, and not at all on the opposite side. The case by Oré, which I related in the preceding lecture (THE LANCET,

These facts clearly prove that a lesion in a lateral half of the spinal marrow produces paralysis only in the corresponding side. It is, therefore, evident that I was right to conclude, in my remarks on the cases reported in my first lecture-1st, that the lesion was only in one half of the cord when there was paralysis only in one side of the body;

FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS OF LONDON, MEMBER OF THE NATIONAL ACADEMY OF SCIENCES (U.S.), ETC.

LECTURE II. - PART I.

ON ORGANIC AFFECTIONS AND INJURIES OF THE SPINAL CORD, PRODUCING SOME OF THE SYMPTOMS OF

SPINAL HEMIPLEGIA.

Facts proving that a lesion in one of the lateral halves of the spinal cord produces: 1st, paralysis of voluntary movements in the same side; 2nd, anesthesia to touch, tickling, painful impressions, and changes of temperature in the opposite side; 3rd, paralysis of the muscular sense in the same side. GENTLEMEN,—Before I proceed to treat of the subject of this lecture I must keep a promise given at the end of the preceding one. I stated that I would soon try to prove that a disease or an injury, either limited to a lateral half of the spinal cord in the cervical region, or occupying transversely a great part or the whole extent of such a half and also a small part of the other half, was the cause of the symptoms observed in the various cases I have related. To give this demonstration, I will show, by a study of each of these symptoms, that they are exactly those which must exist in cases of an alteration limited to a lateral half of the cervical part of the spinal cord, or extending partly also to the other

half.

1st. A lesion in one side of the spinal cord produces a paralysis of voluntary movement in the limbs and trunk on the same side. Since the time of Galen,* who made experiments on this subject, it has been almost universally admitted that a lesion of a lateral half of the spinal cord produces paralysis in the same side in the trunk and limbs. In this century many experimenters, among whom I will name Sir Astley Cooper,+ have repeated one of the experiments of Galen, consisting in a section of a lateral half of the spinal marrow. Most of the vivisectionists state that voluntary movements are completely lost in all parts whose nerves arise from the side of, and behind or below, the transversal section of a lateral half of the spinal cord. Experiments on frogs have led Stilling to deny the exactitude of this assertion. My own researches on dogs, rabbits, and other mammals have, long ago, given the following results:-1st, that voluntary movements are not completely lost behind and on the side of the injury; 2nd, that there is a weakness in the voluntary movements on the opposite side: two facts which give strength to each other to prove that the conductors serving for voluntary movements, in some animals, partly decussate in the spinal nervous centre.§ But clinical facts leave no doubt that, in our species, there is no such decussation in that nervous centre. I need not prove this assertion by reporting the details of these cases, as I shall have hereafter, in this and in other lectures, to give a pretty full account of most of these cases. I will simply say that they show that a lesion, either by a wound (as in the case by See his works "De Locis Affectis," lib. iii., cap. 14; and " De Anatomicis Administrationibus," lib. viii., sect. 6.

+ Medico-Chirurgical Transactions, vol. i., p. 200, et seq.

Untersuchungen über die Functionen des Rückenmarks, Leipzig, 1842, p. 140, et seq.

§ My first researches on this point were published in the Comptes Rendus de la Soc. de Biologie, 1850, p. 195. See also my "Course of Lectures on the Physiology and Pathology of the Central Nervous System," p. 48. In an interesting paper, Dr. Van Kempen (Journal de la Physiol. de l'Homme, &c., vol. ii. 1859, p. 528) announces also that a section of a lateral half of the spinal cord, in the cervical region, in mammals, produces paralysis in both sides, especially in the abdominal limbs. Prof. Vulpian (Leçons sur la Physiol. du Syst. Nerv., p. 384), from different experiments, concludes also that the voluntary motor conductors decussate partly in the spinal marrow. No. 2366.

centre, but much more in one than in the other, when there was paralysis in both sides of the body, but in a much greater degree in one than in the other; 3rd, that the paralysis or its greatest degree was on the side of the lesion or of its greatest extent transversely in the spinal marrow.

2nd. A lesion in one side of the spinal cord produces anæsthesia in the limbs and trunk on the opposite side.-This proposition implies, of course, that the conductors of sensitive impressions decussate in the spinal nervous centre, so that those coming from the left side, for instance, pass first through that side of the cord, and thence into the right side, in which they go up to the brain. The demonstration that this decussation exists in animals and in man is grounded on several series of facts. I will only speak here of the facts relating to our species, referring those persons who might wish to know the facts furnished by vivisections in animals to my publications on that subject. All I will say about animals is, that it may be that in them the decussation of conductors of sensitive impressions is not complete in the spinal cord. In man, as I will prove, the decussation is complete. I will only give here two series of proofs. A. There are a great many cases of disease of the base of the brain, leading forcibly to the conclusion that the conductors of sensitive impressions arising from the trunk and limbs decussate before they reach the brain, and conseI have lately given an quently in the spinal marrow. account of twenty such cases, and also quoted many others. They show that the views put forward by Sir Ch. Bell,‡ Mr. S. Solly,§ and by Prof. Longet, who thought that conductors of sensitive impressions decussate in the base of the brain, must be abandoned. In these cases there was a disease in a part of the base of the brain, near the median plane, having destroyed or altered the nervous tissue only or chiefly of the lateral halves of the brain. Some of the cases relate to the crura cerebri, others to the pons Varolii, and a third set to the medulla oblongata. In all of the cases in which the disease was limited to a lateral half of one of these three parts, there were paralysis and anesthesia in the limbs and trunk on the opposite side, and not in the same side.

If we suppose that the decussation of conductors of sensitive impressions takes place in the upper part of the pons Varolii or between the two crura cerebri, a disease in one of the lateral halves in those parts should certainly produce anæsthesia in both sides of the body, as it would destroy or alter conductors from the side of the disease before they cross to the other side, and also those of this last side after they have crossed and reached the diseased side. there are cases in which one of the crura cerebri, or one side of the pons Varolii in its upper part, was altered, and no such thing as anesthesia on the two sides was observed, the loss of sensibility having been found to exist only in the opposite side.

Now,

The same argument may be used for cases of disease in a lateral half, of the middle or the lower part of the pons, or of the medulla oblongata. The facts relating to these parts are as clear and forcible as those relating to the crura cerebri.T

*I will only quote here two of my publications: Journal de la Physiol. de l'Homme, &c., vol. i., 1858, p. 183; and the Course of Lectures, already cited, p. 29, et seq.

+ See Archives de Physiol. Normale et Pathol., 1868, p. 718.

The Nervous System of the Human Body, 3rd edition, 1844, p. 236. § The Human Brain: its Structure, Physiology, and Diseases. 2nd edition, 1847, p. 242, fig. 94.

Traité d'Anat. et de Physiol. du Syst. Nerveux, 1843, vol. i., pp. 385 & 421. I will only give here the names of some of the observers who have published the cases I allude to. The quotations will be found in my paper already cited. These names are: Andral, Dr. Hermann Weber of London (an excellent observer), Lambroso, Brunnicke, Carré, Friedreich, S. Cooper, my friend Dr. J. W. Ogle, Dr. T. Inman, Gendrin, Broussais, &c.

A

Another argument is as powerful as the preceding: if the decussation of the conductors of sensitive impressions took place above the medulla oblongata, an alteration of a lateral half of that organ would surely produce anesthesia on the same side. I will give here a short summary of a decisive case which proves clearly that the conductors of sensitive impressions do not decussate above the medulla oblongata. CASE 15. Anasthesia and paralysis of voluntary movements in the left side of the trunk and limbs; tumour in, and softening of, the lower part of the pons and almost the whole of the medulla oblongata, on the right side.-A woman, after having recovered from a fit of insensibility, found that she had entirely lost the power of motion in her left arm, and in a great degree also in her left leg. Sensibility of the left side was destroyed. The right side of the face was paralysed of motion and sensibility. The right cornea was ulcerated. Paralysis of all the parts affected became complete, after which she died. The autopsy was made twelve hours after death. A fibrous tumour was found on the right side of the pons. It extended from the origin of the trigeminal nerve down two-thirds of the medulla oblongata; and was about two inches long. The surface of the right crus cerebelli and of the pons, on which it pressed, was softened. It was incorporated with the substance of the right side of the medulla oblongata, and had produced a softening which extended through the posterior tract, but became less as it approached the posterior surface. The anterior tract was a pulpy mass. The left side was healthy.

*

The observer of this case, Dr. S. Annan, justly says,* "The right side of the medulla oblongata was softened to the extent of complete disorganisation. There was complete paralysis of motion and sensation on the left side. The decussation of the fibres of the corpora pyramidalia explains the loss of motion on the opposite side, but as we have no facts proving a similar interlacement of the fibres of the posterior or sensory tract, it is not easy to discover how it happened that the right side was deprived of sensation. Motion and sensation were unimpaired in the extremities of the side diseased. Are we not justified from this in making the inference that there is a decussation of the filaments of sensation as well as those of motion ?" The inference is certainly well grounded, but Dr. Annan did not go further, and left undecided the question whether the decussation of conductors of sensitive impressions takes place below the medulla oblongata-i. e., in the spinal cord or in that medulla, with the motor fibres that form the anterior pyramids.

However strange may appear the supposition, that some of the fibres which decussate to form the anterior pyramids are conductors for sensitive impressions, I must discuss this hypothesis here, as we are led forcibly, not only by Dr. Annan's case, but by many cases of disease of the medulla oblongata and the pons Varolii, to admit either this strange view or the opinion I maintain, that the spinal cord is the place of decussation of the conductors of sensitive impres

sions.

Putting aside all the reasons grounded upon our knowledge of the structure and physiology of the medulla oblongata, which might be brought forward against such a supposition, I will mention two sets of positive facts against it. The first set is furnished to us by vivisections All physiologists who have made experiments on the anterior pyramids agree in admitting that they are not sensitive, and that they can be divided transversely without any appearance of diminution of sensibility anywhere.

The second set of facts, having been observed in our own species, has much more value. In the first place, there are many cases of disease of, or injury to, one or both of the anterior pyramids or their prolongation through the pons Varolii, in which sensibility was not impaired in the trunk and limbs. I shall relate some of these cases in a lecture on the medulla oblongata, contenting myself now with the mention of the principal features of two cases: one showing that the anterior pyramids may be diseased without anæsthesia; and the other, that the conductors of sensitive impressions are placed behind the prolongation of these pyramids in the pons Varolii.

The first of these cases was published by my friend Prof. Lebert. A patient was attacked with general paralysis, increasing slowly but persistently; he suffered from aphonia, difficulty of speech and deglutition, with increasing dyspnea;

*The American Journal of the Medical Sciences. New Series, vol. ii., July 1841, p. 105.

but his senses and general sensibility were unaltered. The autopsy revealed the existence of an aneurismal tumour pressing upon the medulla oblongata. The anterior pyramids, except at their upper part, had been completely destroyed.*

The second case was reported by my late friend Dr. Stuart Cooper. In a patient who had been attacked with anæsthesia in the right limbs, without paralysis, a tumour was found in the left side of the pons, which had not altered the anterior bundles of nerve-fibres (the prolongation of the pyramids).

These two cases complete each other, and leave no doubt that the anterior pyramids are not the channels of sensitive impressions. We can therefore conclude, from the case of Dr. Annan: 1st, that there is no decussation of the conductors of sensitive impressions in the medulla oblongata; 2nd, that these conductors reach that nervous centre having already made their decussation; and, as a necessary consequence from this last conclusion, that the spinal cord is the place where these conductors from one side of the body cross those of the other side.

When I treat of diseases of the base of the brain I will relate other cases of lesion of one side of the medulla oblongata and of the pons Varolii, resembling Dr. Annan's case, and leading to the same conclusions.

Before passing to another subject, I will repeat that many clinical facts positively prove: 1st, that there is no decussation of conductors of sensitive impressions from the trunk and limbs in any part of the base of the brain; 2nd, that these conductors reach the oblong medulla having already made their decussation, so that it is evident that their crossing takes place in the spinal cord. the seat of the decussation of conductors of sensitive imB. The second kind of proof that the spinal marrow is pressions might be considered as useless, owing to the decisive evidence of the first kind of proof, just given, if it were not that this second kind brings with it the demonstration of something more than the fact of a decussation in the spinal nervous centre. The question whether the conductors of sensitive impressions decussate only in certain parts of the spinal marrow, or all along that organ, does not receive the least elucidation from cases of disease of the base of the brain; while it might, on the contrary, be completely solved by cases of disease of, or injury to, the spinal cord. Unfortunately, with only one exception, we have not yet cases in which an autopsy has shown what was the real seat of the lesion when the cervical region of the cord was diseased or wounded; but there are already at least five cases in which a lesion in a lateral half of the spinal cord was found in persons who had had paralysis of voluntary movement on the side of the alteration, and anæsthesia in the opposite side. These cases I will report in a lecture on hemiparaplegia. I will only say now, that they show that the nerve-fibres serving to convey sensitive impressions from the lower limbs and the trunk decussate almost at once after entering the spinal marrow.

Reverting now for a moment to the question above discussed, relating to the anterior pyramids, I will say that these cases of disease of the spinal cord show conclusively that the conductors of sensitive impressions of the trunk and of the lower limbs have no need of a decussation in the medulla oblongata, as they make their crossing in the spinal nervous centre, and, therefore, go up to the base of the brain, those belonging to the left side of the body within the right side of the cord, and those of the right side of the body within the left side of that organ.

These cases prove that a lesion of a lateral half of the cervical region of the spinal marrow must produce anæsthesia in the lower extremity and in the trunk on the opposite side. The case of Oré (Case 14, THE LANCET, December 26th, 1868) shows, besides, that a lesion in one side of that region produces anesthesia also, in the upper limb of the opposite side.

From the two series of proofs I have given, it resultsfirst, that a lesion of one side of the spinal cord, if extensive enough to produce anesthesia, will make it appear in the opposite side of the body, and not in the corresponding one; secondly, that a lesion located in both halves of the spinal marrow, much more extensive transversely in one

* See Traité des Maladies de la Moëlle Epinière. Par Ollivier (d'Angers). 3rd ed., 1837, vol. i., p. 455.

+ See Journal de la Physiologie de l'Homme, &c., vol. i. 1858, p. 761.