LECTURES ON VETERINARY MEDICINE,

LONDON, SATURDAY, MARCH 17.

[1831-32.

far as the sternum, where it is connected with the ensiform cartilage. Immediately under the loins are the appendices of the ON diaphragm, commencing, on the right side, from the inferior surfaces of the five first VETERINARY MEDICINE, lumbar vertebras, by strong tendons which DELIVERED IN THE soon become auscular and form a kind of pillar ; and, on the left, proceeding from UNIVERSITY OF LONDON, the two first lumbar vertebræ only, and BY from the sides rather than the bodies of these vertebrae, and these also unite and MR. YOUATT. form a shorter pillar or leg. The left crus or appendix is shorter than the right, that it may be more out of the way of pressure LECTURE XXII. from the left curvature of the stomach, THE DIAPHRAGM.——THE lI1ECHANISllI OF REwinch, with the spleen, lies underneath. IDIASPIRATION.-RUPTURE OF THE Opposite to the 17th dorsal vertebrae, these PHRAGIII. two pillars unite and form a thick mass of BouNDrNG the thorax posteriorly, the base muscles, detached from the vertebras, and of the cone in the human subject, the inter- leaving a kind of pouch between them and posed curtnin between the thorax and the the vertebrae. They not only unite, but abdomen, is the diaphragm. It is, as you ’, they decussate ; their fibres mingle and will here perceive, an irregular muscular again separate from each other, and then expansion, proceeding from the infenor sur- proceed onward to the central tendinous face of the lumbar vertebrae posteriorly and expansion, towards which the fibres from superiorly, adhering to the ribs on either the circular muscle, and the appendices, side, and extending’ obliquely forward and all converge. The 7’e?zdi?zozts central Expansion.—We downward to the sternum ; or rather, it is a flattened muscle arising from all these sliall presently see that the diaphragm is points, with its fibres all converging towards the main agent, both in ordinary and exthe centre, and terminating there in an ex- traordinary respiration. In its quiescent state, it presents its convex surface towards. pansion of tendinous substance. AnatO1I!!J of the 7?iuphrabm.-In the short the thorax, and its concave one towards the account which I purpose to give of the abdomen. The anterior convexity abuts structure of the diaphragm, I shull follow, as upon the lungs; the posterior concavity of our best is occupied by some of the abdominal vis nearly as I can, the anatomist, Mr. Percivall. You at once per- cera. The effvct of the action of this muscle, ceive that the diaphragm may be divided or the contraction of its fibres, is to lessen into the main circular muscle, with its cen- the convexity towards the chest, and the tral tendinous expansion forming the lower concavity towards the abdomen ;perhaps, contraction, to cause itto part, and two appendices, or cricra, as they by a are called, from their peculiar shape, con- present a plane surface either way. The stitutingits superior portion. We trace the abdominal viscera that must be displaced fleshy origin of the grand muscle, laterally in order to eifect this, have considerable and inferiorly, commencing from the car:i- bulk and weight ; and when the stomach is lage of the eighth rib anteriorly, and follow- distended with food, and the motion re. as

LECTURES

description

powerful

ing pretty closely, the union of the

as we proceed backward, quired from the diaphragm in rapid breathposterior ribs with their ingis both quick aud extensive, there needs

the two some strong, firm, elastic, substance to last. The attachment is peculiarly strong; bear it. The forcible contact and violent it is denticulated ; it encircles the whole pressure would brui-e and otherwise injure of the lateral and inferior part of the chest a mere muscular expansion, and therefore

cartilages ; excepting, however,

No. 446.

846 have this tendinous expansion compa- I heart, and was most plainly to be felt in the of sensibility, to stand the direction of the diaphragm. Again, placing pressure and the shock which will always my hand upon the abdominal muscles, the be greatest at the centre. jerks appeared to come from before backThe Centre of Expansion in other Animals. ward; the impression on my mind, thereThe Ox.-No-vv compare this expansion in fore, was, that it was a spasmodic affection the horse and the ox, the one formed for of the diaphragm, brought on by violent speed and the other for slow work only, distress of breathing." Mr. and for the accumulation of flesh and fat. sued a very judicious mode of treatment. See the wide expanse of tendon in the He administered stimulants. He refrained horse ; the comparatively little development from bleeding until the horse began to ral)y, in the ox. See also the thickness of mus- and the animal did well. cle in the ox, compared with that in the Caution.—This case, Gentlemen, deserves horse. It may be placed here in him with to be treasured in your memories, not only safety; there will seldom be rapid action, as an illustration of the connexion between and his work will be more easily done and comparative anatomy and comparative diswith less exhaustion ; yet occasionally, from ease, but as a most useful guide against an the weight of his paunch, pressing into the error that may be fatal to your patient. Had concave portion of the diaphragm, the la- he mistaken this " audible thumping" for hour will be considerable, although slow. carditis, he would have bled copiously at The Dog.—Look again at the The the first, and nature would have sunk. muscular part of the diaphragm is thick and Use of’ the 41)pet?d*ces.-Ttie use of the the strong, aponeurotic expansion compara- appendices will now be evident. They tively smaller. From the smaller expanse are placed under the loins; at a part at of the thorax in this animal, and the conse- which there will be considerable motion, quent little expansionofthe diaphragm, the when the animal is in rapid progression; action, although occasionally rapid and vio- 1 and more especially if he is carrying lent (for he is an animal of speed), is not weight. The alternate rising or falling of so extensive ; and more muscle and less this portion of the spinal column would, if tendon may be given to him, not only with- the diaphragm were conttnued straight out detriment, but with evident advantage, around, interfere very materially with its Therefore it is, that although we have (;c- action. It would often tighten the diacasional rupture of the heart in the dog, phragm when we wanted it relaxed, and oftener perhaps than in the horse, we have relax it when we wanted to have it to press no rupture of the diaphragm, at least there with considerable and uniform force against is no case of it on record, and no one has the abdominal viscera. It would causeunIn the ox 1 certainty and confusion in the action of this come under my observation. never saw of the heart, and rarely muscle. Now these appendices, insertthat of the diaphragm; and for very suffi- ed so much farther back, and going to join dent reasons, whether we regard the struc- the diaphragm with the obliquity that we here observe, will act as springs beauti. ture or the habits of the animal, Spasm of the Diaphrabnz.-«’hen I look fully and efficiently. The spirial column may at this large aponeurotic expansion and rise and fall, but ccmpat atively little of that will reach the diaphragm; it willbe comparative little muscularower in the diaphragm of the horse, and think of the neutralised or spent as it is communicated frequent thoughtless and cruel exaction of along the fleshy columns which proceed for labour from this portion of the respiratory a while almost parallel with, but separate machine, I cease to wonder at that which from, the spine. We shall see another use was first hinted at by a sporting writer of of them presently. deserved celebrity, and afterwards so well The Openings through the Diaphragm.— described by that accurate observer Mr. There are three. Superiorly you will perCastley. A horse had been 11 a good deal ceive that through which the posterior blowiiin a run of an hour without a aorta passes into the abdomen, and observcheck. When Mr. Castley saw him, " his ing it in the space between the appeathe crura, as it were, stridinn over breathing and attitude indicated the greatest distress. The prominent symptom, how- it, to defend it from pressure and from inever, was a convulsive motion, or jerking jury, you will see a kind and wise provision of the whole body, accompanied by a dull for the safe conduct of a vessel so important thumping noise, audible at several vards as this. distance, and evidently proceeding from his Next, and in the decussation of the crura, inside. The beats appeared to be about and in the most muscular part of the diitforty a minute. On my placing my hand phragm, where its fibres, or the fibres of the over the heart, the action of that organ crura, are crossing each other above and could be felt, but very indistinctly; the below the aperture, passes the 02sopliagus. beatin evidently came from behind the I am not sure that this interwining of muswe

ratively devoid

Castley’pur-

dog.

rupture

motion

,

dices,

847 cular fibres around the oesophagus in this may not combine with the ureterlike entrance of that tube immediately after. wards into the stomach, to produce the difficulty of vomiting in most of our patients ;

place,

at

least I

see

probable danger in forcing

down, instead of extracting any foreign

body firmly wedged in the oesophagus, lest the spasmodic constrictive action which the continued presence of the body, and our efforts to dislodge it, will produce in the muscles of this tube, may be propagated to these neighbouring ones of the diaphragm, and thus to the

an

insurmountable obstacle raised

effecting of our purpose,

Lowest of allis an aperture through the tendinous expansion, and through which the vena cava posterior enters the thorax. It is sufficiently high in the tendinous expansion to be out of the way of pressure, and being placed in that expansion, cannot well be compressed so as to hinder the passage of the blood. It is well said, that the vein is held open by the whole tonic force of the diaphragm. The Tunics of the Diaphragm.—The thoracic or anterior face of the diaphragm is covered by the pleura, of which I shall preseutly speak, and the posteriol or abdominal t’acebv the peritoneum, which belongs to the system. The Arteries and Veins.—This muscle, so important in its office, is plentifully supwith blood-vessels. As the posterior aorta passes beneath the crura of the diaphrag’m, it gives out sometimes a single vessel which soon bifurcates ; sometimes two branches, which speedily plunge into the appendices or crura, while numerous small vessels escaping from them spread As over the central tendinous expansion. the larger muscle of the diaphragm springs from the sides and the base of the chest, it receives many ramifications from the interii-,tl pectoral, derived from the anterior aorta; but more from the posterior intercostals which spring from the posterior

digestive

plifd

aorta.

The veins of the diaphragm belongexelusively to the posterior vena cava. There are usually three on either side ; but they

may be almost referred to two chief trunks which come from the circumference of the diaphragm, and converge towards the centre, and run into the posterior cava, as it passes through the tendinous expansion, The Nerves.—The functional nerve of the diaphragm, or that from which it derives its principal influence, and which constitutes it a muscle of respiration, is the or diaphragmatic. Although it does not proceed from that portion of the medulla oblongata which gives rise to the glosso-pharyngeus and the par vagum, yet there is sufficient to induce us to suspect

phrenic

that it arises from and should be referred to the lateral column between the superior and inferior, the sensitive and motor nerves, and which may be evidently traced from the pons varolii to the very termination of the spinal chord. This specimen illustrates their lateral origin. They do not spring from the lateral column so decidedly as the spinal accessory, and in one continued line, but, as I shall more particularly illustrate when treating of the sensorial system, there is a peculiarity in their origin, and especially from theinferior surface of the chord, which would almost justify us in the conclusion, that, connected with the respiratory nerves in function, they are derived from the same common source. The phrenic nerve first appears consider-

ably lower in the neck in all our patients than in the human being. The precise situation is uncertain. I have sometimes traced a filament from the fourth cervical nerve, which proceeds downward, and uuites with branches from the fifth and sixth, to constitute a perfect nerve ; but in other cases there has been a filament from the fifth, and the nerve has been principally composed of branches from the sixth and seventh cervicals. The more extensive motion in the neck of the quadruped, or the exposure of the superior part of it to injury, might cause a higher origin of the nerve to be inconvenient or unsafe; but, however, once formed, it travels down the neck without any anastamosis ; it enters the chest between the two laminæ of the mediastinum; it passes over the pericardium, where it is a beautiful object in a dissection of the chest, and still pursuing its lonely course, arrives at the centre of the diaphragm, and ramifies over the whole substance of that muscle. Experiments on the Phrenic Xe)-ve.-Sir Charles Bell has instituted some interesting and satisfactory experiments on the function of this diaphragmatic nerve and he has collected some others, at which I will briefly glance. When the phrenic nerves were divided in an ass, a remarkable heaving of the chest took place. Theother auxiliary respiratory muscles, and particularly the intercostals, were labouring hard to supply the deficiency of the diaphragm ; and the chest rose higher than usual, and its margins particularly were more expanded at each inspiration. The spinal accessory was then divided on one side; the mastoid and trapesias muscles on that side ceased to act, yet respiration was violently although imperfectly performed by the intercostals, and the other respiratory muscles, the nerves of which had not been divided. Again, when the spinal marrow at the lower part ofthe neck, and beneath the per-

phrenic

848

formation of the phrenic nerve, was ration is much disturbed, and to obtain the divided, respiration was continued by aid of which he will, under pneumonia, ob-

feet

of the diaphragm. In another stinately stand until he falls exhausted or the phrenic nerves were tirst divided, and to die. then the spinal marrow at the bottom of the Atmospheric Pressure.-Well, the cavity neck. Respiration was stopped inthe of the chest is enlarged. But this is a chest ; but there was a catching and strong cavity, and between its contents and action at intervals of the associate respira- the parietes of the chest a vacuum would tory muscles of the nostrils, and the side of now be formed ; or rather an inequality of the chest. When this animal was appa- atmospheric pressure is produced from the rently dead, he was reanimated by artificial moment the chest begins to dilate. As the breathing, and these muscles again con- diaphragm recedes, there is nothing to counterbalance the pressure of the attracted, but the chest remained at rest. ,The Diaphragm the ’principal Agent in mospheric air communicating with the Respiration.—These experiments are de- lungs through the medium of the nuse or cisive, and mark the diaphragm as the main mouth, and it is forced into the respiratory agent in the work of respiration. The others tubes which have been described in former are mere auxiliaries, httle needed in ordi- lectures, and the lungs are expanded and nary respiration, but affording the most still kept in contact with the receding0 walls important assistance, when the breathing of the chest. There is no sucking, no inhalent power in the act of inspiration ; it is more than usually hurried. The Mechanism of Respiration.—Then the is the simple enlargement of the chest,..mechanism of respiration may perhaps be and thus removing a resistance which the thus explained. I will suppose the lungs pressure of the air could not before overto be in a quiescent state. The act of ex- come, but which once removed, air rushes piration has been performed, and all is still in with a force proportionate to the rapidity and quiet. From cause enveloped in mys- or the extent of the removal. tery-connected with the will, but inde- Act of Expiration.—From some cause, as as that which produced the expendent of it-some stimulus of an unexplained and unknown kind-the phrenic pansion of the chest, the respiratory nerves nerve acts on the diaphragm, and that mus- cease to act, and the diaphragm by the incle contracts; and by contracting its con- herent elasticity of its tendinous expansion vexity into the thorax is diminished, and and muscular fibres, returns to its natuthe cavity of the thorax is enlarged. At ral form, projecting its convexity into the the same time, and by some consentaneousthorax ; the abdominal muscles, which influence, the intercostal muscles act, with bad been put on the stretch by the forcing in undisturbed of the viscera into the posterior part of the no great force indeed breathing, but in proportion as they do actabdomen, means of the straightening of ’ the ribs rotate on their axes, their edges are the diaphragm, contract, and accelerate the thrown outward, and thus a twofold effect return of that muscle to its quiescent ensues;—theposterior margin of the thorax figure ; and the ribs, all armed with elastic is expanded, and the cavity is plainly en- cartilages, and those cartilages bent in such larged, and also by the partial rotation of angles as to dispose them most rapidly and every rib the cavity is still more increased; perfectly to regain their former figure, - at the same time, this bellying out of fall again; and the muscles of the shoulder the parietes of the chest is an antagonist and the chest relax, and the lungs are pressed to, and limits the too powerful contraction on every side, and the air with which they were distended is partially forced out again. of, the diaphragm. Auxiliary Muscles.—By some consenta- There is only one set of muscles actively neous influence, the spinal accessory likeemployed in expiration, namely, the abdowise exerts its power, and the sterno- minal,-the elasticity of the parts displaced maxillaris is stimulated by the anterior dt- in inspiration would almost alone accomvision, and the motion of the head and neck plish the purpose. corresponds with, and assists that of the The Elasticity of the Lungs.—The lungs chest; while the posterior, by its anasta- are not altogether passive. The bronchial moses with the motor nerves of the leva- tubes, so far as we have been enabled to tor humerus and the splenius, and many trace them, are lined with cartilage, divided other of the muscles of the neck and the for the purpose of folding up when the lungs shoulder, and by its direct influence on the are compressed, but elastic enough to afford rhomboideus, associates almost every mus- a yielding resistance against both unusual cle of the neck, the shoulder, and the chest, expansion and contraction. In their usual in the expansion of the thorax. These are state the air-tubes are distended beyond muscles, however, which, in undisturbed their natural calibre. The proof of this is, respiration, the animal scarcely needs, but that if the parietes of the thorax are perwhich are necessary to him when the respi- forated, and the pressure of the atmosphere

means

case

closed

inexplicable

and

by

most

849 is thus rendered equal within and without this must of necessity be fatal. It is some them, thelungs immediately collapse. Their what difficult, however, to describe the elasticity is then no mean agent in the act of symptoms by which such an accident may

of the be clearly designated. ’]’lie breathing must abdominal muscles this principle has much of necessity be most laborious, yet not the to do. short, quick, and painful respiration of inIts Effect on the Heart.-This constant fiammation, but a slower, more laboured, effort at contraction in the lungs answers double effort at expiration. Is it always fatal?—Although a lesion such another very important purpose. The heart is inclosed in the thoracic cavity. It is ex- as this must of necessity be fatal, a question arose, whether a slighter rupture of the dia.« posed to the pressure of the air, which, bearing with its full force on this plirac-m might not exist for a long time, organ, would not permit it to heat; but just only characterised by disordered respiration. in proportion to the resiliency or elastic re- Not only the possibility, hut the actual ocsistance to expansion in the cartilaginous or currence of it has been demonstrated. Concellular texture of the lungs, the weight sider, Gentlemen, the horizontal position of or pressure upon the heart is taken away the thorax of the horse, and imagine a or neutralised. The resiliency of the lungs small rupture towards the lower part of it. and the pressure of the external air are The lung will not protrude into the abdo-’ probably more ncarly balanced than we men, but from the powerful pressure of the abdominal muscles on a cavity not defended sometimes imagine, Here we will at present leave the mere by bony walls, some portion of the intesmechanism of respiration. This muscle tines will be forced against or into the having so much to do must be occasionally thorax. While strangulation does not take subject to injury. I’have hinted at that place, the injury will produce nothing more spasmodic action which is often the morbid than disordered respiration, and that possiconsequence of exhaustion, and I would bly not to a great degree. It may even be again urge you to be on your guard that you difficult to distinguish it from broken wind. A remarkable case of Chronic Rupture.— do not confound it with carditis, a ’disease proceeding from a very different cause, and A horse died of supposed enteritis: on examination the diaphragm was ruptured, and requiring almost opposite treatment. Inflammation oj’ the Diaphragm.—The a portion of intestine had insinuated itself French writers speak of inflammation of the through the aperture. It was strangulated, diaphragm. I can conceive such a disease and mortified. This must have taken some to be not only a possible but probable occur- time to accomplish ; but as an irrefragable rence; but I have not met with it ;-there proof of its being a long-standing case, the is no English record of it, and I must be edges of the rupture were nearly healed, content, unwillingly so, with their account and a quarter of an inch in thickness. of the matter. They speak of fever, cough, Another horse on the 25th of December difficulty of respiration, convulsive beating received a violent kick on the right side, of the Ranks, cerebral irritation, convul- which brolie one of his ribs. His respirasions, fury, and the last to such an extent as tion immediately became exceedingly quickto be confounded with rabies. Every case ened and laborious, and continued so for was unsuccessful in spite of the most vigor- some hours, when suddenly it resumed almost its natural character. He remained ous treatment. an accithe quiet more than a week, when ho was Rupture of Diaphragm.—Of dent to which this muscle is exposed, seized with violent colic and constipation namely rupture, we unfortunately know and fever, which occurred occasionally for more. There are cases on record of rup- the space of five weeks when he died, but tured diaphragm in the human being, but apparently from inflammation of the wound. principally as connected with laborious par- A rupture was found towards the inferior turition, the rationale of which it is easy to part of the diaphragm, and the greater part understand. In the horse it is the usual of the small intestine had passed through consequence of over-exertion. Mr. Cart- it, and occupied the right side of the thorax, wright, 1 think, mentions a case in which and there was strong adhesion of the intesit occurred in the mare at the time of par- tine to both of the pleuræ; and, what was most extraordinary of all, a portion of the turition. A Case ny Fatal Rupture.—Mr. Hales of intestine had glided along the 7th rib, and Oswestry records a case in which a mare passed between the longitudinal opening driven long at a quick pace suddenlv show- caused by the upper part of the fracture, and ed symptoms of distress ; it was with great had entangled itself between the ribs and difficulty that she could be got home to her the subscapularis muscle, forming a second btable, and died in two hours. The rent hernia. extended from the ensiform cartilage to the’ The rupture of the diaphragm had evicentre Qf the diaphragm. Such a lesion as dently taken place at the moment of the

expiration, and even in the contraction

atmospheric

850 blow.

The extreme

to Dr. Willan. Rayer, however, all the diseases of the skin itself into of intestine insinuating itself into the orifice, the passage those which are simply inflammatory, and That is a general was closed, and the breathing became as those which are not. quiet as before. Colicky pains, however, division. The order of arrangement of those attended the threatened or incipient stran- which are inflammatory is, I think, rather gulation of the intestine ; but the animal objectionable, and might be more natural. lived five weeks, and was cheerful and play- The mode in which, at the London Univer this year, I have considered the in. ful a few days before his death. May it be connected with Broken Wind?— flammatory diseases of the skin, has been Then it being’ ascertained that a lesion of following, audgentlemen there consider their views, and been the diaphragm may exist for a considerable that it has time, and not be characterised by any pe- very convenient to the memory :culiarly laborious respiration, another ques- I divided them first, with Rayer, into tion arises, whether it may not occasionally those which are inflammatory and those exist as a cause of broken wind ; for it is a which are not-those which have nothing singular fact, that in many of the cases of to do with inflammation. ruptured diaphragm that are on record, the Then those which are inflammatory I horse was broken-winded. Was broken arranged in this way : I took those which wind the result of the rupture, or the rup- consisted of simple inflammation---.nothing ture the consequence of the increased dif- more than mere redness of the skin. The ficulty in expelling the air arising from latter kind may be considered, first, as seen broken wind? One thing, however, should only in separate spots, or, second, only on not be forgotten, that rupture of the dia- a continuous surface. phragm is in all probability much oftener Now those which produce only inflamma. induced by the struggles of death, than tory spots are lichen, strofulus, or recl-gum, and prurigo3 these little red spots are called previously existing. This is a difficult as well as a new sub- papulœ. ject, and we must await the result of many Then those which affect a continuity of a careful observation, ere we fully make up the surface, and produce continuous redness, our minds on it. or rashes, are exanthemata. Such are measles, Rupture of the diaphragm is the occa such is scarlet fever, such is erythema, such is roseola-red patches of inflammation. sional consequence of hoove in the ox. Then we go a step farther, and consider those inflammatory diseases which produce something more than redness—which clevate the cuticle beneath by fluid; and these ST. THOMAS’S HOSPITAL. may do so either by producing serum, clear fluid, or by producing pus, so that we have vesicular or pustular disease of the skin. CLINICAL LECTURE Of the former kind is the miliary eruption, BY such is pemphigus or pompholyx, such is JOHN ELLIOTSON, M.D., F.R.S. herpes, such is eczema. Then, again, we have to consider those PROFESSOR OF THE PRINCIPLES AND in which the inflammatton elevates the PRACTICE OF MEDICINE cuticle by pus, and these are all pustular IN THE UNIVERSITY OF LONDON, diseases. Small-pox and ecthyma are instances of this, and there are various others, Delivered February 9th, 1832. all characterised by the formation of pus. Now this is an exceedingly simple order

proved this ;

but

a

difficulty of respiration states,

divides

portion

sity

the

ARRANGEMENT OF CUTANEOUS

simplified

DISEASES,

of arrangement, and you thus have only to consider whether a disease affects the skin THERE are a few cases, Gentlemen, of itself with inflammation or not. Then, if diseases of the skin, which have gone out, inflammation, to consider whether it and to which I will refer as illustrating the produces simple inflammation, or elevates variety of treatment which is necessary in the cuticle by serum or pus. If it produces different circumstances of these affections. inflammation, you have only to conThe mode of arranging diseases of the sider whether it occurs in spots or is difin patches. If there be fluid you skin, followed by Rayer, is better than that of Willan. Rayer, whose work is the very only to consider whether it be serum best on the subject, and which it would be or pus. Now there are several diseases which I worth while for every one who reads French is not translated, is would class together, but which are sepato possess, and I indebted for the ground-work of the greater !! rated by some writers ; for instance, take SIMPHFIED

TO ASSIST THE MEMORY.

with

simple fused

! have

regret

part of his arrangement,

as

he himself those which consist of inflammation in

mere