HEArTH SCIENCES STANW HX64101282 >101 .G91 1921 The blood supply t ap iot n- 1 Digitized by the Internet Archive in 2010 with funding from Columbia University Libraries http://www.archive.org/details/bloodsupplytoheaOOgros THE BLOOD SUPPLY TO THE HEART THE BLOOD SUPPLY TO THE HEART IN ITS ANATOMICAL AND CLINICAL ASPECTS BY LOUIS GROSS, M.D..C.M. Douglas Fellow in Pathology, McGill University, and Research Associate, Royal Victoria Hospital, Montreal With an Introduction by HORST OERTEL Strathcona Professor of Pathology, McGill University, Montreal WITH TWENTY-NINE FULL PAGE PLATES AND SIX TEXT ILLUSTRATIONS PAUL B. HOEBER NEW YORK Copyright, 192 i Bv PAUL B. HOEBER Printed in the United States of America TO MY ALMA MATER AND ALL THOSE FROM WHOM SHE DREW HER GREATNESS AND NOBILITY THIS BOOK IS DEDICATED ON THE OCCASION OF THE MC GILL UNIVERSITY CENTENNIAL OCTOBER, NINETEEN HUNDRED AND TWENTY-ONE INTRODUCTION This monograph on the blood supply to the heart in its anatomical and clinical aspects is the outcome of investiga- tions which Dr. Gross commenced several years ago in the laboratories of the Royal Victoria Hospital and of McGill University. They formed originally part of a general study dealing with structural evolution of organs in the various age periods in its relation to normal function and disease. 1 It soon became apparent to me that in these researches Dr. Gross had, with rare industry and ingenuity, gone far beyond the original questions and that the results of his work touch upon a larger number of problems which are not only of anatomical, but also of great clinical interest and impor- tance. The extent of the work and the accumulated material and illustrations had also gone far beyond the original scope of a paper and it was therefore considered advisable to publish it in monograph form. This allowed a further extension and inclusion of a thorough critical review, and incorporation of previous literature — by itself a useful undertaking. The work, therefore, places before us: First: A complete description of the arterial and venous blood supply to the normal heart with a statistical study of its variations. Second: The blood supply to the neuromuscular system of His and its pathological and clinical significance. ■See Ocrtel, Post-Natal Development and Pathological Organ Reconstruction in Relation to Function and Disease, Am. J. M. Sc, May, 1921, p. 694. viii INTRODUCTION Third: A new standpoint in the discussion of the anatomical factors concerning the etiology and development of valvular endocarditis. Fourth: A newer view on the physiological course and character of the cardiac circulation in the various age periods and their relation to physiological and pathological functions. The monograph contains, so far as I know, a complete presentation of the subject to date and possesses for anatomist, physiologist, pathologist and clinician alike an unusual com- bination of interest and usefulness. Mr. Hoeber's rare good will to publish the work is an illustration of his unselfish, scientific spirit. Horst Oertel. McGill University ;ind The Roy;il Victoria Hospital, Laboratories of Pathology. Montreal, July, 1921. PREFACE The author was primarily interested in the study of the circulation of the heart in its relation to age periods and in its pathological variations. For a lull appreciation of the changes in the cardiac circulatory architecture under these conditions, it was found advisable to make a thorough study of the normal. A review oi the literature proved inadequate to allow an intelligent grasp oi the subject and only served to perplex by its chaotic state. With much difficulty it was attempted to coordinate the various views, and there remained many points of dispute and a large number ol problems. The author con- sequently made a personal study of the circulatory struc- ture in the normal heart in order to investigate as many ol the moot points as possible and also to acquire a standard lor comparison with the results ol future investigations into pathological conditions. hi the course ol this research a technique was developed, which, it is believed, is eminently suited lor investigations of this nature. Main of the disputed points have been, it is hoped, settled and a number of new and interesting fields for speculation, opened. Chief among the latter is the question ol tin- effect of age on the course, character and physiologj ol the cardiac circulation. It was found that a very charac- teristic series ol changes takes place as age progresses. This appears, In itself, an interesting contribution to the clinical x PREFACE appreciation of the physiology and pathology of senile heart and death. The blood supply to the neuromuscular system was worked out with care. It was found that the anatomy of the neuro- muscular circulatory structure could be intelligently correlated with functional derangements such as presented by classical cases found in the literature. Moreover, much of the reported experimental work acquired a new meaning. With the results of a series of experi- ments which the author himself undertook, the anatomical factors which enter into the production of valvular endocarditis have been put in a position which appears to throw new light upon the clinical and anatomical experiences of previous investigators. In view of the accumulation of these facts and the work that was required to make a thorough search into the litera- ture, Professor Horst Oertel suggested to present the whole matter in monograph form. It has consequently been decided to present in these pages a summary of the state of our know- ledge on this subject. For convenience in handling the matter, it has been divided into eight chapters. It is true that the divisions overlap somewhat, but in this way the historical review oi the various problems is much more comprehensively handled. The general plan is to give a concise historical survey of the matter dealt with in a chapter, indicating briefly the technique employed by the various investigators; then to outline the present state of knowledge and finally to add the author's contribution. Appended is a bibliography arranged in alphabetical form. As far as possible, this was made complete. Unavoidably, PREFACE xi some contributions must have been left out, but it is hoped that the bibliography forms in itself a complete chain of evi- dence, reflecting the phases of thought through which the subject has passed. The cross index should render the book of more ready reference and increase its usefulness. The author wishes to take this opportunity to thank Prof. Horst Oertel for his generous and sympathetic advice throughout the work. To Dr. J. D. Morgan, roentgenologist of the Royal Victoria Hospital, and to Mr. Black of the United Photographic Store, Montreal, he is much indebted for the beau- tiful roentgenograms, plates and photographs which have made the work possible. To Mr. H. E. Webster, Superintendent of the Royal Victoria Hospital, who has kindly supplied apparatus and laboratory facilities, to Drs. Semple, Pitts, Waugh and Branch for autopsy material, and to his wife for invaluable aid in preparing the bibliography, the author also wishes to express his appreciation. Not the least of these, he owes thanks to Mr. Paul B. Hoeber for the kindly interest he has taken in publishing this work. L. G. McGill University and The Royal Victoria Hospital, Laboratories of Pathology. Montreal, July, 192 1. CONTENTS CHAPTER PACK I. Technique i II. The Blood Supply to i hi : Ventricles and Auricles. ... 11 III. Variation in the Distribution of the Coronary Arteries . 26 [V. The Blood Supply to the Neuromuscular Tissue 37 V. The Blood Supply to the Heart Valves and Its Relation to the Inflammations of the Valves 53 VI. The Anastomoses Between the Coronary Arteries. ... 77 VII. The Veins of the Heart 93 VIII. Age Period Changes in the Blood Supply to the Heart and Their Pathogenetic Relations 105 Bibliography 153 [ndi \ [65 LIST OF ILLUSTRATIONS FIGURE PAGE i. Flanged Glass Nozzle 4 2. Flanged Metal Needle 5 3. Injection Apparatus 6 4. Roentgenogram of the Blood Supply in the Average Heart 13 5. Photograph of injected and cleared specimen, showing the ulti- mate Subendocardial Distribution of the Coronary Arteries i - 6. Diagram of cross section through the heart showing the regions supplied by the Left and Right Coronary Arteries 24 7. Roentgenogram of a typical variation in Coronary Artery Distribution 27 8. Photograph ol injected and cleared specimen, showing the Blood Supply to the Neuromuscular Tissue on the Right Side 45 9. Photograph of injected specimen, showing the Blood Supply to the Aortic Cusp of the Mitral Valve which is the seat ot an Acute Endocarditis 59 10. Photograph of the Tricuspid Valve from the same Heart as in Fig. 9 61 11. Photograph of the Pulmonary Valve from the same Heart as in Fig. 9 63 12. Photograph of the Aortic Valve from the same Heart as in Fig. 9, showing the Blood Supply to the Cusps 65 13. Photograph of injected specimen, showing the Blood Supply to the Aortic Leaflet of a Normal Mitral Valve 69 14. Photograph of injected and cleared specimen, showing the Anastomoses on the Anterior Surface of the Heart 8~ 15. Roentgenogram of the Venous Distribution in the Average Heart. 95 16. Graph showing the increase of Subpericardial Fatty Tissue as Age Aws s,> characteristic a course that it merits the name of Ramus ostii Cavae superioris. The second anterior branch to the auricles from the right coronarj arterj i^ less constant. It ascends the aortic face of the right auricular appendage and distributes itself o\ er the 22 THE BLOOD SUPPLY TO THE HEART roof of the right auricle, approaching the origin of the superior vena cava. Very occasionally a lateral branch is given off at the margo acutus, which ramifies over the external surface of the right auricle, approaching the opening of the inferior as well as that of the superior vena cava. A number of very small and inconstant auricular vessels may be seen besides those described above, but since there is nothing characteristic about these and since they are with difficulty distinguishable from vessels which supply the pericardial fat, the description of these will be taken up under the heading of Arteriae telae adiposae cordis. The left coronary artery shows, with the exception of the ramus ostii cavae superioris already described, one or two smaller auricular branches which distribute themselves over the anterior surface and roof of the left auricle. Occasionally a lett lateral auricular branch extends around the posterior surface of the auricle to reach the opening of the superior vena cava. ARTERIAE TELAE ADIPOSAE CORDIS Besides the main vessels which have thus far been de- scribed, there are a number of interesting and important branches which apparently occupy both anatomically and functionally a category of their own, because considered from both these viewpoints they seem to occupy a place half way between that of the vasa vasorum and the cardiac coronary branches proper. These are what may be called fat branches (Arteriae telae adiposae). They are seen in greatest number in the fat found under the pericardium — namely, in the grooves between THE BLOOD SUPPLY TO THE VENTRICLES 25 the chambers, where they occur as an irregular felt-work, and over the sites of the main coronary branches, where they exist as delicate parallel accompanying vessels whose distance from the main branches varies directly with the amount of fat present (Figs. 24 and 25). The rich interanastomosing network of delicate vessels, superimposed upon the outer coats of the root of the aorta and of the pulmonary artery, falls under this category. These fat-vessels arise largely from the first portions of the arteria circumflexa sinistra and dextra as well as from their branches soon after their origin. In a later chapter their importance and significance will be shown. BLOOD SUPPLY TO THE HEART AS A WHOLE It is of considerable interest and importance to coordinate the description giver afc>0"\ e of tin' distribution of the individual coronary arteries and consider the supply of the heart as a whole as well as of its specific parts. Numerous investigators have attempted to inject both coronary arteries at the same time, and, by using a differently colored injection mass for each coronarx artery, have obtained results which in some measure help to throw light on those regions of the heart which are supplied by both. Amenomiya, Nussbaum and Sternberg have contributed much valuable information in this direction. It must first of all be remembered that there can be no sharp line of demarcation between the supply of right and left coronarj arteries, since, not only do their branches OS crlap, but also, as will later be shown, profuse and abundant anas- tomoses leave a wick- borderline which is supplied by both vessels. A rather arbitrary division will therefore be given, 24 THE BLOOD SUPPLY TO THE HEART first, of the supply of each artery; secondly, of the common supply by both vessels. Since the auricular distribution of blood-vessels is so prone to variations that an attempt at giving a typical descrip- tion becomes artificial and practically worthless, this will be left to the consideration of variations. The following descrip- tion, therefore, answers in a rather unsatisfactory way for the supply to the ventricles. Fig. 6. — Diagram of cross section through the heart, showing regions supplied by the [eft and right coronary arteries. Lines running from right to left represent the supply of the left coronary artery. Lines running from left to right represent the supply of the right coronary artery. The crossed areas represent supply from both vessels. From the description which has been given above, it can readily be appreciated that the right coronary artery in the typical average heart supplies the entire right ventricle with the exception of the left third of the anterior wall. Besides this, its rami ventriculares sinistri supply the right half of the posterior wall of the left ventricle and a small strip of the interventricular septum (Fig. 6). THE BLOOD SUPPLY TO THE VENTRICLES 25 The left coronary artery, on the other hand, supplies the whole remaining part of the left ventricle-, the small [eft anterior portion of the right ventricle not supplied by the right coronary artery and a small anterior strip of the inter- ventricular septum. The areas of junction on the posterior surface of the left ventricle and on the anterior surface of the right ventricle where these divisions meet, are supplied by both vessels. Thus, the intervening portion of the interventricular septum is supplied by branches from the ramus descendens posterior dexter and ramus descendens anterior sinister and the pos- terior papillary muscle of the left ventricle by the rami ventricu- Iares sinistri from the right and the rami marginales'from the kit coronary artery. At least a portion of the anterior papil- lary muscle of the right ventricle is supplied from the rami inter- \ entriculares from the left and the rami anteriores fromthe right corona 1 \ artery. Indeed, it is quite easy to trace a distinct large \ cssel through the trabecula septomarginal to this papillary muscle, which appears to supply the greater volume of its blood to this region. The large anterior papillary muscle oi the [eft ventricle receives its blood from the rami marginales and the inconstant posterior papillary muscle of the right ventricle from the rami posteriores of the right coronary artery. Chapter III Variations in the Distribution of the Coronary Arteries AS has been indicated, the coronary arteries are rather prone to variations. It is this disposition to variations which renders their description somew hat artificial and rigid. There appears, however, to be one typical variation which is rather constant and which will be described here. For the reason that the other possible variations assume clinical and pathological interest, a table classifying a statis- tieal analytical study of the course and character of the coronary arteries will follow. If one makes a review comparing the general characteristics of the average distribution of left and right coronary arteries, one is struck by the fact that the main stout ramus descendens anterior of the left coronary artery has its counterpart in the ramus descendens posterior of the right; furthermore, that the left coronary artery seems to trespass on the anterior surface of the right ventricle and falls somewhat short of supplying completely the left ventricle posteriorly. The main scheme, therefore, in so far as the ventricular supply is concerned, seems to be a sort of twisting of the vessels in a direction from left to right anteriorly and right to Ieit posteriorly. An examination of what is termed the typical variation (Fig. 7) shows, first of all, that both the anterior and posterior rami descendentes come from the left coronary; secondly, that the rather aborted ramus circumflexus sinister, which is 26 Fie. 7. — Roentgenogram of a typical variation in coronary artery dirtribution. 27 VARIATIONS IN THE CORONARY ARTERIES 29 seen in the normal heart, is represented here by a verj typical and characteristic circumflex branch which imitates accurately that found normally on the right side. Thus, even the branches, which have been described as originating for the most part from the fork of the two main corollaries normally, in tins instance arise from the left coronary artery all along its course through the auriculoventricular sulcus and up to a point where it, again imitating the right coronary artery, abruptly bends downward at the site of the crux and proceeds to the lower third of the heart. The third striking feature is the verj much aborted and simplified right coronary artery. The ramus circumilexus, now resembling that normally found on the [eft side, ends at the margo acutus and gives oil some delicate branches, one of which continues in the auriculoventricular sulcus towards the crux, the others presenting a rather scant supply oxer the posterior face of the right ventricle. The main body of the right coronary turns abruptly down at the margo acutus and finally attenuates itself toward the apex. For the rest, the subdivisions of this vessel on the anterior surface ol the light ventricle is similar to that found in the normal. The auricular supply in this type shows no characteristic variation. STATISTICAL ANALYSIS OF THE VARIATIONS The site- of origin of the coronary arteries shows consider- able variation. Since, as Tandler points out, the old discussion between Morgagni and Fantoni and later between Ilyrtl and Brticke, as to the importance of the site of opening oi the COronarj arteries in connection with the position ol the semilunar cusps in systole, has lost its significance, it is suffi- cient to state with Piquand that they arise in the center 30 THE BLOOD SUPPLY TO THE HEART line of the sinus of Valsalva somewhat anteriorly to the inser- tion of the cusps. So far as the number of the coronary arteries at their origin is concerned, it is interesting to note that Morgagni, Cruveilhier, HyrtI, Bochdalek and Engelmann have described cases where the total blood supply to the heart came from a singly existing coronary artery. Fallopius and Riolanus held that normally one coronary artery exists in the heart. Morgagni, however, showed that two exist. Occasionally more than two coronary arteries spring from the aorta. In such instances the accessory branch or branches represent twigs which, in the ordinary course of events, spring from the main coronary, but which, in these cases, arise directly from the aorta close to the origin of the main stem. Tandler states that this multiple origin of coronaries is found on both sides, more frequently on the left. Out of the ioo cases studied by the author, in four instances a second origin of a coronary artery was seen; of these, two were on the left side and two on the right. Here the accessory coronary pursues a course identical with one of the rami ventriculares anteriores. The accessory openings in the left anterior sinus of Valsalva were somewhat to the left of the opening of the main coronary artery. Of those on the right side, one arose to the left, and the other, below and to the right of the main coronary artery. That this condition occurs more frequently than reported and is often missed, seems quite possible, since the accessory coronary branch is usually very small and, unless a careful dissection is made or an injection directly down the lumen of the aorta carried out, the condition can easilv be overlooked. DISTRIBUTION OF THE CORONARY ARTERIES 31 Although occurring relatively infrequently, the condition assumes some clinical importance, for an obliteration of a main coronary artery which [eaves intact an accessory twig may enable a heart, which has had time to adapt itself to the diminution in its blood supply, to carry on a relatively un- disturbed function. VARIATIONS IN IIU-: MAIN BRANCHES In considering the variations occurring in the main branches of the coronary arteries, it has been decided to present these in table form. This can conveniently be expressed by categorizing, according to their site of origin and main course, the branches in the 100 hearts which were very care- fully studied, indicating the percentage in which they occurred singly, as two branches, three, etc. In the text which follows each chart, a more detailed discussion on the qualitative nature of the variations is given. TABLE I.— ARTERIA CORONARIA DEXTRA SUPPLY TO VENTRICLES Number ctf Branches 1 2 | 3 4 5 4 $6 47 13 «H I 6 84 8 2 ■- Z Rami Ventriculares Dextri Posteriores. 48 4 o 8| 4 1 8 92 o| - - ,6 J 2 22 | 18 1(1 2 - TABLE II.— TERMINATION OE RAMUS CIRCUMFLEXES DEXTER Margo Acutus Crux Between Crux and Margo Obtusus Margo Obtusus 4 pel Kill 10 per cent 'id per cent 20 per nt 32 THE BLOOD SUPPLY TO THE HEART Where several rami anteriores exist, they course somewhat diagonally across the anterior surface of the right ventricle and approach the ramus descendens sinister at right angles. In their course they are parallel and relatively equidistant to one another. They do not dichotomise with frequency in their main stems but rather towards the end of their course on the surface of the heart. Where the rami anteriores occur in smaller numbers, they proceed in a line drawn to the apex, giving off all the while parallel and more or less equidistant branches to the right and principally to the left side in a manner very similar to those described above. The ramus lateralis, as will be seen in Table I, occurs most frequently singly. Here it descends in somewhat tortuous fashion towards the apex, divides before reaching it and distributes branches to the anterior and posterior aspect of the lower portion of the right ventricle. The rami posteriores are infrequent. Occurring usually singly, they have a short course parallel to the ramus lateralis. The ramus descendens posterior terminates in 5 per cent of the cases at the upper third of the posterior Interventricular sulcus, in 27 per cent at the middle, in 39 per cent in the lower third, and in 20. per cent at the apex. When the rami ventrfculares sinistri occur multiple, they are given off, as a general rule, fairly close one to the other near the crux, spending themselves in their coarser distribution on the inner and upper half of the posterior surface ot the left ventricle. Of the termination of the ramus circumllexus dexter (Table II), it need only be said that 66 per cent end somewhere between DISTRIBUTION OF THE CORONARY ARTERIES 33 the crux and the margo obtusus. Of these, 41 per cent end hall- way between the two points. TABLE III.— ARTERIA CORONARIA DEXTRA SUPPLY TO AURICLES . 1 2 3 Rami Anteriores | 1 1 | 52 | 26 11 ■= Kami Laterales | 62 | 36 | 2 M = Kami Auricula res Dextri Posteriores 79 16 | 5 ^ = Rami Auriculares Sinistri Posteriores | 84 | 12 | 4 - As has been pointed out before, with the exception of the stout branch to the junction of the superior vena cava with the right auricle {Ramus ostii cavse superioris), the auricular branches are rather inconstant in their distribution. In a great number of cases the branches are so small that the borderline between those which may be called auricular branches, and those which fall into the category of fat branches, is \cr> uncertain. It is noteworthy that, although both auricular as well as fat branches usually arise from the main ramus circum- llexus, the\ also take origin from the beginning of the ventricu- lar branches. As will be seen by the nomenclature (Table III), the divi- sion of these branches into groups according to their site of origin is purely arbitrary, since this may not, and often does not, correspond with their ultimate distribution. Thus, a ramus auricularis sinister posterior is occasionally seen to cross the region of the interauricular septum from left to right and ultimately to arborize on the right side of the right auricle. Indeed, it is not infrequently found that the vessels pursue a bizarre course and supply at random almost any conceivable portion ol the auricles irrespective ol the original site ol origin. 34 THE BLOOD SUPPLY TO THE HEART It is true, however, that to a certain extent a branch will supply that portion of the auricle which it first crosses and in this way there is some correlation between the nomenclature and the function of the vessel. It is on account of this rather inconstant supply of these vessels that it has been decided to give, at the end of this chapter, an analysis of the blood supply to the auricles in bulk, that is, stating approximately the ratio of auricles sup- plied from the left and right coronary arteries. TABLE IV.— ARTERIA CORONARIA SINISTRA SUPPLY TO VENTRICLES Number of Branches 1 2 3 4 5 6 Ramus Descendens Anterior 100 6 23 45 14 6 6 Rami Posteriores 84 8 6 2 = 3 Ramus Descendens Posterior 92 | 8 c Ramus Ventricularis Dexter 92 | 7 1 TABLE V.— TERMINATION OF RAMUS DESCENDENS ANTERIOR Lower Third of Lower Third of Middle of Anterior Apex Posterior Posterior Interventricular Interventricular Interventricular Sulcus Sulcus Sulcus 2 per cent 38 per cent 52 per cent 8 per cent TABLE VI.— TERMINATION OF RAMUS CIRCUMFLEXUS SINISTER I Between Margo Margo Obtusus j Obtusus Crux 86 per cent 2 per cent Crux 10 per cent Between Crux and Margo Acutus 2 per cent DISTRIBUTION OF THE CORONARY ARTERIES 35 Here it must be noted, first, that the- ramus descendens anterior gives a number of branches to the right ventricle, which run in the same direction and meet the rami anteriores from the right coronary artery. Secondly, the rami marginis obtusi, which are represented on the right side by the rami anteriores and Iaterales, arise, as pointed out before, somewhere on tlie left ventricular aspect of the ramus descendens and ramus circumllcxus sinister. The variations, here, are charac- terized by a shifting of their site of origin anywhere from the extent of the ramus descendens to the ramus circumllcxus as far as the junction of the margo obtusus with the posterior surface of the left ventricle. The greater number of these diagonally running vessels come oil the ramus descendens, the lowermost terminating their superficial course on the anterior surface of the left ventricle in the region of the apex. The remainder, together with those taking origin from the ramus circumllcxus, round the margo obtusus to reach the posteroexternal portion ol the [eft \ entricle. There are usually one or two branches from the ramus circumllcxus opposite the center of the margo obtusus, which are larger than the remaining rami marginales and which extend downward towards the apex. Tlie first characteristic variation to be considered is the termination of the ramus descendens anterior. It will be seen in Table V that the site of election is the lower third of the posterior interventricular furrow. In tins regard it is to be remembered that the final, minute termination extends much farther. The place, however, where the superficial and coarser circulation ends has been used as the point of termination. In (S4 per cent of the eases there were no distinct rami 36 THE BLOOD SUPPLY TO THE HEART posteriores and in these cases the posterolateral surface of the left ventricle was supplied by continuations of the rami marginis obtusi. Rami descendentes posteriores occurred only in instances where the ramus circumllexus reached the crux. In the same instances rami ventriculares dextri were given off, usually only one; in one case, three (Table IV). TABLE VII.— ARTERIA CORONARIA SINISTRA SUPPLY TO AURICLES | i 2 3 | 5 | 45 1 27 | 23 | 77 23 | <) erf C Rami Auriculares Sinistri Posteriores | 86 14 1 Si = Rami Auriculares Dextri Posteriores | i 0. The same remarks as to the inconstancy in course and character of the auricular branches, which were made for the rami auriculares from the arteria coronaria dextra, apply equally well to those from the arteria coronaria sinistra. It will be noted in Table VII that there are no branches arising from that part of the ramus circumllexus sinister which occasionally (in 2 per cent of cases, Table VI) extends beyond the crux to the right side. This, of course, does not mean that auricular branches from the left coronary artery do not extend over to the right side, for this is, as a matter of fact, not infre- quently seen. Upon examining the roentgenograms carefully, it was found that in 44 per cent of the cases most of the circulation to both auricles came from the right coronary artery; in 36 per cent of the cases, the distribution of auricular branches and vascular structure was about equal from the right and left DISTRIBUTION OF THE CORONARY ARTERIES 37 corollaries, and in 20 per tent ol the cases most of the blood came from the left coronary artery. It is interesting to note, in this connection, what an impor- tant role the ramus ostn cava' supcrioris plays, for in 82 per cent ol those cases winch showed a preponderance oi supply from the right side, then' existed a ramus ostii cavae supcrioris taking origin from the- right coronary artery. In 100 per cent ol the cases where the preponderant supply was from the lelt coronary artery, the ramus ostii cavae supcrioris arose from tin same side. Taken altogether, the ramus ostii arose from the right coronary artery in 60 per cent of the cases, and from the left in 40 per cent. From the foregoing description of the variations which occur in the branching and ultimate distribution ol the coronary arteries, it follows that the heart as a whole, as well as its parts, e.g., septum and papillary muscles, presents functional differences corresponding to these variations, an observation which is rather important clinically and anatomi- cally, lor, whereas for example, in the typical blood supply an infarction and necrosis of the posterior papillary muscle of the left side would indicate a closure of branches from both sides, m the typical variation which has been described, closure ol one or two rami postcriorcs from the left coronary alone would cause the same condition. Again, when the ramus circumflexus dexter reaches the margo obtusus (20 per cent 1, obliteration ol it alone would lead to a total necrosis ol that muscle; as also with the supply to the interventricular septum. The most frequent seat of variations, so far as suppb from lelt or right is concerned, lies in the extent of supply to the posterior wall of the heart. As has been noted, this ma\ vary 38 THE BLOOD SUPPLY TO THE HEART from cases where branches from the left coronary artery extend practically to the margo acutus, to where branches from the right coronary artery extend to the margo obtusus. In these instances the region of the heart supplied by each, as well as the region of the heart receiving blood from both, will vary with the anatomy of the circulatory structure. Chapter IV The Blood Supply to the Neuromuscular Tissue IN describing the blood supply to the conducting apparatus of the heart, to which, among others, notable contribu- tions have been made by Purkinje, Gaskell, Kent, W. His, Jr., Keith and black, Aschoff and Tawara, Moenckeberg, Koch, Fahr, Hering and Erlanger, it is deemed advisable to give a short description of this structure in order to review its morphology and, therefore, appreciate better the specificity of its vascular architecture as well as the functional significance of the latter. This structure which, despite the objections by some observers, as Dogiel, is now held to be responsible lor the orderly origin and conduction ol impulses from auricles to ventricles, consists of: (a) two mam nodes which are, according to Thorel, united by a specially differentiated strand of tissue, but, according to Keith and Hack and Koch, ununited except b\ the ordinary musculature ol the auricles; b) a main auriculoventricular conducting bundle which divides into two limbs lor right and left ventricles; (c) a very rich and profuse arborization ol the limbs in both ventricles. Ol the two main nodes, one, known as the sino-auricular, Ins in the sulcus at the [unction ol the superior vena cava with the right auricle, more on its anterior aspect. The other, known as tin- auriculoventricular node, lies within the mouth, and extends t<> the lelt ol the opening ol the sinus coronarius into the right auricle. It is certain that the mam conducting or S9 4 o THE BLOOD SUPPLY TO THE HEART His bundle is a direct continuation of the latter, which, lying in a sheath (described by Curran) penetrates the septum fibrosum. This is from i to 3 mm. in width and 1 to 2 cm. in length and usually runs along the lower border of the pars membranacea septi where it divides into a right and left septal branch which saddle the top of the interventricular septum. The right limb extends into the vestigial moderator band (Trabecula septomarginalis, Ta-ndler) as a fairly distinct column which may or may not course superficially. Here it breaks up into an extensive interlacing and interanastomosing network of fibers which are generously distributed over the internal surface of the right ventricular wall. The left limb passes over the top of the interventricular septum and, soon spreading into a fan-shaped, thin and fiat structure, distributes itself over the interior surface of the left ventricle in two divisions. These are called, according to their location on the interventricular septum, fasciculus anterior and fasciculus posterior. So far as the histology of this structure is concerned, it may be stated briefly that the nodes and main bundle are made up of a meshwork of narrow, somewhat fusiform fibers with more or less indistinct striations. These cells gradually give way, as they ramify in the ventricles, to large pale fibers of relatively undifferentiated protoplasm with striations clearly seen in their outer strata. The nuclei of the main bundle are numerous and always surrounded by a perinuclear space; those of the ultimate ramifications never occur together and are always near the border of the cells. In 1907 Keith and Flack first pointed out that the sino- auricular node possesses a distinct and specific blood vascular system. This was substantiated in 1909 by Koch, who described BLOOD SUPPLY TO NEUROMUSCULAR TISSUE 41 in greater detail a stout branch from the right coronary artery , which courses between the aorta and mesial wall of the right auricle to penetrate the interauricular septum and sends a twig to surround posteriorly the cava sulcus. Here it anas- tomoses with a delicate auricular branch which arises from the mam coronary in this situation and ascends between the musculae pectinati, passing practically free through the interstices. The vessels now pass the situation of Wenckebach's bundle and pierce through the sino-auricular node. In [906 Tawara described a special blood supply to the auriculoventricular node, the main bundle and its chief divi- sions. This was later described by Keith and Flack as a relatively large branch ol the right coronary artery which accom- panies the main bundle as it penetrates the annulus librosus. Moenckeberg (1908) described vessels supplying the auri- culoventricular node and the main bundle but did not consider them specific or constant in their supply. He had seen a thick \ essel emerging from the auricular septum to enter the bundle and divide into many small vessels which accompany the stem ol the bundle forward. From these, two branches continue to the anterior portion of the bundle up to the point of division. Spalteholz (1909) observed a delicate vessel entering the bundle but was unable to determine its ultimate course. In [910 Georg Haas published the results of his researches in this direction, lie employed differently colored injection masses lor each coronary artery, filling, in some cases, a single coronarj artery; in others, both at the same time. Isolating what he believed to be the specific branch to the auriculoventricular nodal system, he also attempted to inject this branch alone, but was unsuccessful on account of technical difficulties. 42 THE BLOOD SUPPLY TO THE HEART Haas's experiments consisted in injections, dissections and serial sections of human, dogs' and calves' hearts, and from these he came in part to the following conclusions: In man the right coronary artery plays the chief role, supplying two branches from the posterior coronary arch. First, a ramus septi ventri- culorum superior, which supplies the upper posterior half of the septum, piercing into the left ventricle and supplying the posterior divisions of the neuromuscular limb in this situation. Secondly, a ramus septi fibrosi which, coursing through the auricular septum, sends several branches through the septum fibrosum to the inner muscular layers of both ventricles and finally, as a stout twig, enters Tawara's node and loses itself in the main bundle and beginnings of both neuromuscular limbs. The anterior branches to the left main limb are supplied by fine twigs from the left coronary artery; the right limb lies just on the border between the regions of arborization of the right and left coronary arteries in the septum. He is of the firm opinion that in the human heart, no anastomoses exist between the right and left coronary arteries in the auriculoventricular node and main bundle. From a study made on ioo hearts, the author is of the opinion that a distinct and specific blood supply exists for both sino-auricular and auriculoventricular nodes, the main bundle, the first portion of the left limb and a large part of the right limb of the neuromuscular system. The remainder shows a supply which corresponds to the area of heart musculature upon which it rests. The discrepancies in the otherwise excellent work oi Haas are probably due to technical errors, Haas himself admitting difficulties. Dissections in an uncleared specimen, even though perfectly injected, are at best open to error, and serial sections, though throwing much light on the microscopic appearance of capillaries, etc., are eminently unreliable for coarser reconstruction. Fig. 8. Photograph <>! injected and cleared specimen, showing the blood supply to the neuromuscular tissue on the right side. P. NEUROMUSCULAR TISSUE 45 Figure 8 shows an injection by the method described by the author in the chapter on technique. Here it is seen quite clearly that a very stout and characteristic branch which arises close to the origin of the right coronary artery, in this case makes a fairly direct course for the region of the sino- auricular node and is called, on account of its obviouslj specific supply, the Ramus ostii cava superioris. As its detailed de- scription has already been given (Chapter II), it need only be pointed out that though this vessel is more or less character- istic in its ultimate supply, it is not absolutely fixed in its origin, for it may arise from either left or right coronary arterj . Furthermore, the author has been unable to find the character- istic twig which Koch describes as arising from the main coronary close to the origin of the inferior vena cava and passing practically free through the interstices of the muscular pectinati, but has found instead: First, that several auricular branches in the vicinity give oil numerous anastomotic twigs; secondly, the ramus ostii cavae superioris shows extensive anastomoses with its own branches; thirdly, in certain instances where the ramus ostii cavae superioris arises from the left coronary artery mot pointed out by Koch) it may either supply the nodal tissue only as it passes this site anteriorly, other auricular branches contributing largely to the ring-shaped encircling arterial structure, or, it may bifurcate as it reaches the cava funnel and encircle it with two embracing branches which anastomose freely with each other as well as with other auricular branches in the region of the external surface of the right auricle; fourthly, the author has failed to find a \ essil which lies, on the whole, free in the interstices of the musculac pectinati. rhere are never two rami ostii cavae superiores, always 46 THE BLOOD SUPPLY TO THE HEART one. No blood-vessels have been found to show a supply for a specific tissue which might connect the sino-auricular with the auriculoventricular node, an observation which is confirm- atory of Koch's. Figure 8aIso shows the ramussepti jibrosi. This corresponds, except for a few details, very well with the description given by Haas. It arises invariably from the crux, and since this is crossed most frequently by the ramus circumilexus of the right coronary artery, it receives its blood usually, though not invariably, from this source. Coursing directly anteriorly it gives branches to the neighboring tissues, one of which, usually a stout twig, is fairly constantly seen supplying the superior portion of the interventricular septum. The main (though occasionally more delicate) vessel, however, plunges into the auriculoventricular node and accompanies this as it gives way to the main bundle, and often the bundle in its primary divisions. Just as the ramus septi fibrosi represents really a superior septal branch from the ramus descendens posterior, even so its behavior is similar to these, inasmuch as it receives anas- tomoses from the superior septal branches of the left coronary artery. These septal branches can readily be seen in a cleared specimen. They curve close under the insertion of the right aortic cusp, in the musculature of the interventricular septum, sometimes better seen on the left side, and approaching the undefended space, ramify in the neuromuscular tissue in the septum iibrosum, anastomosing with the corresponding vessel from the right side. The main point of difference in the circulation as de- scribed here, with that of Haas, lies in the existence of anas- NEUROMUSCULAR TISSUE 47 tomoses which take place- between branches from the left as well as the right coronary arteries. In a case cited by Haas this anatomical construction is borne out. This concerns a heart where there occurred em- bolization of the ramus septi fibrosi with hemorrhagic infarc- tion oi the interauricular septum and the muscular divisions which enter into the nodal structure. The anterior portion of the node was preserved though much altered by inflammation. Here, Haas states, perhaps anastomoses occurred with the ramus superior septi ventriculorum or with the anterior septal artery. The right limb ol the neuromuscular bundle, as has been stated, pursues a practically uninterrupted course through the trabecula septomarginalis. Throughout, it is accompanied by a stout vessel {Ramus limbi dextri) derived from one of the earliest divisions of the ramus descendens sinister, and really representing a septal branch. At the base of the trabec- ula, twigs from the rami anteriores ol the right coronary aitcr \ penetrate and anastomose with the ramus limbi dextri. The ultimate' arborizations are supplied from the rich subendocardial vessels which have been described on page 10, and correspond in their nutrition with the area ol heart musculature upon which they lie. The left limb of the' neuromuscular structure has no specific blood supply ol its own, but derives its nourishment on its septal aspect from the' profuse anastomoses of septal branches from both siele's, the fasciculus anterior receiving more blood from the' ielt coronary artery, and the fasciculus posterior, from the' right. For the' rest, here, as in the right ventricle, the ultimate' divisions \ar\ in their blood supply according to their situation on the' heart musculature. 48 THE BLOOD SUPPLY TO THE HEART It is important to remember that variations in the vascular architecture will profoundly alter the blood supply to the neuromuscular tissue. It has already been pointed out that the sino-auricular node is supplied from the right coronary artery in 60 per cent of the cases examined, and from the left, in 40 per cent. Since the ramus septi fibrosi arises from that coronary artery which passes the crux, it follows that its origin is as follows: (a) Right Coronary Artery 86 per cent (b) Left Coronary Artery 4 per cent (c) Possible from left or right 10 per cent The percentage of possibilities from left or right is due to the fact that this figure represents the proportion of cases where both left and right ramus circumflexus reach the crux. In these cases, 6 per cent of the possibilities came from the right and 4 per cent from the left, so that the final figures are: (a) Right Coronary Artery 92 per cent (b) Left Coronary Artery 8 per cent As with the ramus ostii cavae superioris, this branch always arises from one side, never from both. Since no variations were found in the occurrence of the rami interventrieulorum from the ramus descendens anterior sinis- ter, at least in our cases, it maybe assumed that the Iimbus dex- ter of the neuromuscular tissue invariably derives its blood from the left coronary artery. So far as the blood supply of the fasciculi of the Iimbus sinister on their septal aspect is concerned, in those cases where the ramus descendens posterior arose from the left coronary artery (8 per cent) they were supplied wholly from NEUROMUSCULAR TISSUE 49 tin's artery. This, as will be noted, corresponds to the ratio ol supply to the auriculoventricular node from the same side. In the other <)2 per cent, both coronary arteries contributed to their supply. The ultimate distribution of the Purkinje libers also corre- sponds, as regards their blood supply, to the variations described in Chapter III. To bring out the clinical and pathological importance ol this vascular arrangement, as well as to lend support to the anatomical description, there follows a series of eases described by Moenckeberg, in which distinct pathological lesions ol the neuromuscular structure are traced to interference with its Specific blood supply. It is already well known that this tissue at times shares pathological processes with the rest of the heart musculature; at times escapes; and, at times, is the sole part affected in generalized hematogenous disl urbances. Moenckeberg, lor example, has shown that in a ease ol endo- and focal myocarditis, a distinct infiltration and con- gestion ol the neuromuscular tissue occurred. In some eases of brown atrophy, the bundle contained fat and much more brown pigment than the muscular tissue proper. One east' of arteriosclerosis and brown atrophy ol the heart showed an absence of pigment in the limbus sinister. In a male, aged seventy-seven, who died ol pyelonephritis, heart failure and brown atrophy of the heart, the bundle was very fatty but contained no brown pigment. Moenckeberg attributes this discrepancj in the pigmenta- tion of the bundle to the fact that pigmentation must be advanced before it affects the bundle. 5 o THE BLOOD SUPPLY TO THE HEART In another case dying from general peritonitis, fatty rings were found only in the bundle. It is to be remembered that normally the bundle contains fat. In a case of thoracic mesaortitis with stenosis ol a coronary artery, there was no necrotic lesion in the bundle. This case assumes particular significance when, by contrast, a series is examined where this bundle artery has been blocked. Thus, in a male, aged eighty-two, who ''lowed clinically the Stokes- Adams syndrome with bradycardia and dissociation, and who presented at autopsy a heart with concentric hypertrophy ol the left ventricle and considerable sclerosis of the main coronary arteries with, however, patent lumina, a scar was found at the site of the bundle. As Moenckeberg could find no other explanation for this, other than embolic blocking, he came to the conclusion that "this condition is, however, only to be explained by assuming a distinct and specific artery to the bundle, and in this way the above case supports the view that the blocked bundle must have contained a specific vessel." In Case xxiv of Moenckeberg's series, there is an interest- ing illustration of the specificity of supply to the bundle. In an individual, aged sixty-three, who died with arterio- sclerotic kidney, there was found arteriosclerosis of the coro- naries with old closure of the right and many scars in the heart muscle. The septum in the region oj the bundle was scarred, but the bundle itself was intact. Here evidently the vasculature to the bundle was functioning perfectly. That scarring may be scattered in the bundle so that some of the fibers are spared, is illustrated in G*.se xxv. This concerns a male, aged seventy-five, who died of heart block, general arteriosclerosis and atheroma of the coronary arteries. Here, there was found scarring at the origin of the bundle but NEUR0M1 SCULAR TISSUE 51 a number of fibers passed through intact. Evidently the block n;_ r was only in some of the finer divisions of the ramus septi fibrosi. Additional a posteriori evidence of the existence ol a specific bund e blood supply is found in Case XXVI. A male, aged fifty-seven, who showed at post-mortem coronary arterio- sclerosis, chronic heart aneurysm, old mitral endocarditis, etc., presented an intact Ik .idle lying on an extensively and thoroughly scarred subjacent and surrounding tissue. Case LIX showed, similarly, anemic necrosis of the septum with the bundle inl So far as the effect of coronary arterj obliteration on the ultimate distribution and function of the neuromuscular structure is concerned, it can be stated that the outlook is much brighter, for though the infarctions show their greatest extent on the internal surface of the heart, the very rich and profuse subendocardial anastomoses generally supply sufficient nourishment to the superimposed Purkmjc libers to keep them intact. Of course, where scarring has been so extensive as to involve the whole thickness of the wall and include the endo- cardium, there, undoubtedly, disappearance of the Purkinje fibers takes place, for it is very doubtful whether the ventricu- lar blood can supply sufficient nourishment to keep the sensi- tive neuromuscular tissue alive. This does not, however, express itself necessarily in arrhythmias, since- there is adequate and ample interanastomosing of the neuromuscular tissue- within the chambers to supply and make up for gaps. On the other hand, it will be shown in Chapter VIII that the nutri- tion of the innermost layer of heart wall varies considerably in its supplj with the age of the individual, becoming much 52 THE BLOOD SUPPLY TO THE HEART richer and better able to stand arterial obliteration as age progresses. This has apparently been recognized to a certain extent by Haas, for in a ease which he cites, where there was an atheromatous obliteration of the ramus septi ventriculorum superior with anemic infarction of the posterior portion of the septum and adjoining part of the left ventricle, the subendo- cardial musculature was intact. This, he explains, was due cither to plentiful blood supply to this layer, or to nourishment from the blood contents of the ventricle. Finally, Moenckeberg had already concluded that variabil- ity must exist in the blood supply to the heart and conse- quently in the original source of blood to the neuromuscular structure, for he observed that blockage of the same part of a coronary artery produced, in different hearts, different results in the bundle. This conclusion is amply supported by the variations which are described in Chapter III. Chapter \ The Blood Supply- to the Heart Valves and its Relation to the Inflammations of the Valves WITH the possible exception of the chapter dealing with the existence of anastomoses in the heart, no part ol cardiac vascular morphology has been the subject of so much controversy as that on the blood supply to the val\ es. Apart from its anatomical interest, Koster's acceptance oi the existence of blood-vessels in valves as a basis lor his theorj of embolic endocarditis has brought additional importance to this question and has precipitated two distinct schools of thought. One of these denies the existence of vessels in normal valves and holds with Riihle that endocarditis 1 is caused by adhesion of bacteria from the main blood-stream to the valves. 1 he selection ol the closing edge as the usual primary seat ol the lesion is, according to this opinion, due to the fact that the \al\e is here exposed to the greatest mechanical compression during diastole and systole, in the case ol semilunar and auricu- [oventricular valves respectively. This, perhaps, together with a greater phagocj tic power of the cells in this locality, accounts for the great frequence ol endocarditis at this site. I he other school claims that blood-vessels normally exist in valves and that bacteria] emboli lodge in the site of greatest constriction, ' I In endocarditis referred to in this chapter is the valvulai variety. 53 54 THE BLOOD SUPPLY TO THE HEART namely, where the delicate capillary arborizations take place at the closing edge; here, therefore, a septic focus with inflam- mation, rapid involvement of the overlying endocardium and thrombosis occurs. Luschka was the first to claim that auriculoventricular as well as semilunar valves were vascularized. He stated that the semilunar valves receive their blood supply from the vasa vasorum as well as from the richly vascularized endocardium and that the auriculoventricular valves receive their blood supply from the attached edge as well as from the papillary muscles, through vessels which run along the chordae tendineae. He described these vessels as forming an arterial network in the main portion of the valve leaflets, accompanied by veins, and breaking up into more delicate strands which eventually end as capillaries at the closing edge. He also correlated the frequency of endocarditis on the aortic leaflet of the mitral valve with the relative ease with which blood-vessels can be found in this situation. Rokitansky, Virchow, Joseph, and later Cadiat opposed these views, whereas Gerlaeh, Forster, KoIIiker and Rosen- stein confirmed them. A third group, represented chiefly by Sappey, Frey, Henle and Coen arose, who stated that blood-vessels exist in the auriculoventricular valves, but not in the semilunar cusps. Langer modified this view in pointing out that blood- \tssels exist in those valves where muscle fiber remains are to be found. This was followed a year later by Darier whose conclusions are in part as follows: (a) There never exist any vessels in the libro-elastic part of the auriculo- \ entricular valves. BLOOD SUPPLY TO THE HEART VALVES 55 • In The valves of the tricuspid and the left mitral leaflet are, as a rule, entirely fibro-elastic; the aortic leaflet of the mitral valve presents vascu- lature only in its upper part, generally not more than one-sixth of its length. (c) In newborn children, one sees muscular bundles penetrating more or less to the tore in all auriculoventricular valves. (d) In pathological changes in the valves, \csscls are seen throughout the entire extent of the semilunar, tricuspid and mitral valves. (e) These vessels seem to be the result of inflammations. (J ) Those writers who have succeeded in injecting the vascular network of the aortic and mitral valves have obtained pathological appearances. (g) The valvular hematomata found in the newborn appear coincident witli the processes (if regression of vessels which occur in the valves during the letal period. Darier's conclusions have here been stated somewhat in detail, for in the subsequent discussion they acquire import- ance. Odmzow later confirmed the results ol Langer and Darier and these were again accepted by Koniger. Recently, Nussbanm has described a tortuous vasculature, which extends about 3 mm. from the base of the auriculo- ventricular valves into the leaflet, but no farther. He was unable to demonstrate blood-vessels in t he semilunar \alves. In 1 1 > 1 Bayne-Jones injected 14 human hearts: 6 from the first decade of hie, 2 from the second, 2 from the third and 4 between the ages ol thirty and sixty. Out of these 14 hearts he was able to obtain a fairly complete injection in 3. In some ol the others onl\ irregular groups ol vessels were seen which branched into delicate arteriole's extending to the line of closure of the valves. A description based on the three most completely injected hearts shows that the mitral and tricuspid valves receive a distinct x asculari/ation from delicate twigs which arise from t he annular branches ol the right and lelt coronary arteries, and not 56 THE BLOOD SUPPLY TO THE HEART Irom vessels extending from the auricular musculature. The blood- vessels extend to the line of closure, where they form abundant anastomoses. Only occasionally do small vessels pass from the line of closure to the free edge of the valve. In the upper portions of the valves Bayne- Jones was able to demonstrate veins which showed characteristic differences from the arteries. The chordae tendineae showed blood-vessels which reached almost to the insertion into the valves, but never, in the human, actually passed on to the valve. Bayne- Jones also succeeded in injecting 3 aortic and more pulmonary valves. The source of blood supply to these corre- sponds to the description already given by Luschka. The injec- tion extended usually from the base of the cusp half-way to the edge. A few tiny vessels could be seen at the line of closure. \\ ith all this conflicting evidence, therefore, it is not strange that there should be much dissension, and that some should claim, as does Darier, that blood-vessels exist onk where there has been inflammation, and others, that blood- vessels occur in perfectly normal valves and that the idea of their non-existence is due to the inability of the observers to demonstrate them. Bayne-Jones, in fact, believes that technical difficulties account for most of the failures. He insists that the heart must be kept until rigor mortis passes off; that all cut edges as well as venous exits must be tied off; and that injec- tion with a fine gelatine must be carried on at a pressure of from 160-190 mm. Hg to obtain satisfactory results. It can easily be seen that the conception of the existence of blood-vessels in valves is essential to the theory of embolic endocarditis. Finally, there is the third group to consider, represented THE BLOOD SUPPLY TO THE HEART VALVES 57 by Langcr and others, who claim that blood-vessels occur in those situations where muscular remains persist. From the experiments carried on by the author, as well as from a different interpretation of the literature on this ques- tion, it seems that each ol these conflicting views is correct if taken in part, and that they can all be coordinated into a logical and reasonable explanation lor the genesis and mech- anism of at least many cases ol" acute valvular endocarditis. As Tandler states, since kiirschner's description of the musculature found in the valves of human hearts, numerous in\ est iga tors have followed with descriptions and studies ol the frequency ol occurrence of this tissue in the valves, ol its relation to the age of the individual, and of its source from auri- cle or ventricle. It seems quite clear that the auricular musculature which is quite abundant in fetal valves, becomes less so as the in- dividual l the mitral valve. 6. The aortic cusp of the mitral valve is the last to show -2 THE BLOOD SUPPLY TO THE HEART regression of musculature and the most frequently injected leaf. 7. Practically all cases of valvular endocarditis show a distinct vasculature. 8. Relatively few normal heart valves show in the adult a vasculature, the frequency being somewhat greater than the occurrence of persistent muscular strands. To these may be added: 9. Hearts which show congenital anomalies, arrests in development, very frequently show also an endocarditis, and this, moreover, is more frequently the case on that side and at that location where the arrest of development is seen, particu- larly where this bears a close association with interference with the embryonic valve anlage. In such cases one would expect perversions and arrests of normal vascular regression on the same side. This view is lent considerable support by a study, very kindly made for the author by Dr. Maude E. Abbott, on the incidence of acute endocarditis in 581 congenital cardiac defects. The following is a short excerpt in table form from these cases: Number Acute nj Cases Endocarditis Anomalous Septa In left auricle 7 o In right auricle 3 1 In ventricles 2 o Dejects of Auricular Septum Patent foramen ovale High auricular septal defect Low auricular septal defect Defects of Interventricular Septum Defects at base Defects elsewhere than at base 19 9 12 4 34 9 3 THE BLOOD SUPPLY TO THE HEART VALVES 73 (The four cases of acute endocarditis occurring in the low auricular septal defects with persistent ostium primum and consequent cleavage of the anterior segment of the mitral valve, presented vegetations on the valves of the left siclc.i In this group, the close relationship between the occurrence of acute endocarditis and delects which involve the reg I the auriculoventricular valve anlage, is of considerable significance. Number Acute oj Cases ' Endocarditis Cor Biloculare and Triloculare. 23 o Deject itf Aortic Septum Complete defect (persistent truncus) 13 o Partial delect (with defect ol ventricular septum ' 1 1 lieu- it is found that a complete absence ol septum formation is nut associated with the occurrence >>l acute endocarditis. In the cases, how- ever, where there was an aborted attempt at this formation, endocarditis was found. Number Acute of ('uses Endocarditis Pulmonary Stenosis 82 21 Pulmonary Atresia. 24 1 Subaortic Stenosis. 8 3 (on left side) Aortic Stenosis 6 o Aortic Atn sia 3 o Tricuspid Stenosis 2 o Tricuspid Atresia. 10 2 Mitral Stenosis . . . . . 1 Mitral Atresia 3 o Anomalies oj Auriculoventricular Valves 12 Although not so suggestive, these figures indicate the importance ol defects which produce stenosis, in connection with endocarditis, and emphasize the frequencj with which this occurrence is on the right side. Other cases are considered which, though not so pertinent to this question, indicate, nevertheless, that the anatomical factor ol narrowing vasculature, which maj indeed l)e second- - 4 THE BLOOD SUPPLY TO THE HEART ary to a wear-and-tear scarring process, is intimately asso- ciated with the occurrence of endocarditis. It would appear from these premises that only a certain percentage of postnatal hearts contain persistent fetal vas- culature of valves and that valvular endocarditis may be caused by embolization of bacteria in these persistent vessels. But as this persistence is, fortunately, relatively infrequent, it follows that the incidence of valvular endocarditis, resulting from an embolizing bacteremia due to organisms which are causative agents of this disease, will bear a relation to the frequency with which blood-vessels are found in the valves. It would, therefore, be important to obtain figures of this incidence at different age periods in relation to the occurrence of blood-vessels in the valves. This figure, it is believed, would probably represent very closely the proportion of cases of endocarditis. Just as an individual in whom other fetal structures persist, is exposed to the possibility of their disease, so, it is the author's opinion, the individual, whose valvular vascu- lature has not undergone regression, is liable or predisposed to a valvular endocarditis. If endocarditis were caused only by bacterial adhesions to the closing edge of a valve where compression is greatest, it does not seem quite clear why the aortic cusp of the mitral valve should be the most frequent to suffer. Nevertheless, it is not the author's intention to deny the possibility of valvular infection by way of the main blood-stream, as indeed it seems to occur in parietal endocarditis (toxic form as shown by de Vecchi, or bacterial form, by Ribbert), but it appears desirable to emphasize that in view of the considerations pre- sented above, it is probable that an individual who has THE BLOOD SUPPLY TO THE HEART VALVES 75 persistent valvular blood-vessels is certainly additionally exposed to endocarditis. Here the compression at the edges would serve as still another factor, besides the narrowing of the blood-stream, for precipitation of bacterial clumps. Tlie heart valves are peculiar in that they are the only structures in the body which undergo periodic compressions by a force equal to the weight of approximately 100 mm. Hg and over. Moreover, these compressions, according to Howell, occur seventy times a minute and last 0.379 second in the case of auriculoventricular valves, and 0.483 second in the case of semilunar valves. In other words, the capillaries in the edges of the auriculoventricular valves are compressed for 10.612 hours during the day, and those of the semilunar valves, 13.524 hours. This would afford an excellent oppor- tunity for the arrest and development of pathogenic bacteria. It may be argued that the incidence of endocarditis in certain infections, such as rheumatic lexer, is so common that the relative infrequency oi persistent vasculature in valves is here of little importance. But this objection loses much weight in the light of stricter criticism, for hospital statistics are no indication of the relative proportion of the occurrence of endocarditis in rheumatic lexer. Moreover, Osier's statement and general clinical experience, that the insusceptibility to en- docarditis diminishes as age advances, are stronglj suggestive of the influence of age on the regressive anatomical changes in tin valvular vasculature. It must also be borne in mind that other factors besides the mechanical may enter into the occurrence of an endo- carditis; for, whereas certain bacteria max require compression lor settlement and action at the closing edge of a valve, other, perhaps more virulent, organisms max be enabled 76 THE BLOOD SUPPLY TO THE HEART to localize and set up inflammation in a part of a vessel not submitted to this mechanism. Thus, ulcerative endo- carditis is known to arise relatively frequently in other por- tions of the endocardium and in the valve leaflet. Here, the fact that occasionally the valvular vessels terminate before reaching the edge, may serve as a focus of bacterial arrest. This was well illustrated in several typical cases recently injected by the author. Finally, through lack of sufficient material the author unfortunately cannot give accurate statistics from his own observations on the frequency with which valves can be injected during the different age periods, but it would be of great importance to obtain exact information in regard to the percentage of successful injections in increasing age, for it appears probable that the latter would be accompanied by a decreasing percentage. Those who have attempted to inject blood-vessels in valves have, therefore, failed in a great many instances, not only on account of an imperfect technique, but doubtless also because of the normal evolution of heart valves which in adult life usually causes a complete disappearance of vessels. Chapter VI The Anastomoses Between the Coronary Arteries EVEN though the question as to the existence of anas- tomoses between the coronary arteries has been the subject of long controversy and discussion, it can now with certaintv be stated that, to this at least, a final answer has been given. The question of anastomoses resolves itself into three gn nips: (i) Do anastomosis exist between the right and left coronary arteries both in their capillary and precapillary distribution? : Do anastomoses exist between branches of each coronary artery? 13) Do anastomoses exist between the coronary arteries and \essels of the adjacent and attached organs? The sources of information on these questions have been extraordinary both in the number of contributors and investi- gators, as well as in the methods employed for its elucidation. The following classification shows how varied were the factors which the different observers employed singly and in combination in these investigations: a) Dissection. Experimental tying-off of coronary arteries or their branches, ehiclb in dogs, to determine, by evidence of infarct formation or rapidity with which heart stoppage occurred, the existence or non-existence of anastomoses. 78 THE BLOOD SUPPLY TO THE HEART (c) Injection of colored gelatines into both arteries. (d) Injections of a colored gelatine into one coronary artery to see whether it passes out of the other. (e) Serial section and reconstruction of injected specimens. (/) Injection of metals with subsequent corrosion. (g) Injection of gelatine suspensions of heavy salts with subsequent roentgenography. (h) Injection of colored gelatines with clearing of the remaining tissue. ( i ) Examination and dissection of pathological specimens showing obliteration of branches. (/') Observation of clinical cases with, frequently, autopsy examinations. To these, the author has added: (k) Injection of vessels with a gelatine suspension of a heavy salt by a special technique which standardizes all mechanical factors. This is followed by stereoscopic roentgen- ography of the organ, clearing, dissection and microscopic section. Normal as well as pathological hearts were used for the purpose. (See Chapter I.) The first historical experiments on the effect of tying-off a coronary artery in a dog were those made by Chirac in 1698. These, however, threw no light on the question of anastomoses, since the only observation made by him was that the heart ceased beating. It was not until 1708 that Thebesius, followed later by Haller, Morgagni and Senac, on the basis of careful dissections, came to the conclusion that anastomoses exist between both coronary arteries. Haller stated that these were quite rich and occurred with frequency at the root of the pulmonary artery, in the posterior sulcus Iongitudinalis, in the right ventricle, ANASTOMOSES BETWEEN CORONARY ARTERIES -9 at the apex of the heart, on the surface of the ventricles and through the vasa vasorum of the great vessels. In [799 Parry and Jenner (cited by Parry) first interpreted the clinical syndrome known as angina pectoris as due to cal- cification of the coronary arteries and the autopsy findings on John Hunter's heart, after Jenner had diagnosed his condition, corroborated this vievt . In 1810 Caldani's dissections revived the claim that anas- tomoses exist, particularly at the root of the pulmonary artery. Cruveilhier again described wide anastomoses between both coronarj arteries as well as with bronchial arteries. In 1842 Erichsen published his results of experimental ligature ol coronaries in animals and concluded that "any circumstance that may interfere with passage of blood through the coronary arteries either directly, as in ossification of the coats of those vessels, or indirectly, by there not being sufficient blood sent out of the left ventricle as in cases of extreme obstruction or regurgitant disease of the aortic or mitral valve, may occasion the fatal event." In [855 HyrtI, on the basis of injection and corrosion experiments, categorically denied the existence of anastomosis between the coronary arteries and this was confirmed in 1866 by Ilenle, who stated, however, that capillary anastomoses do occur. Krause was the first to oppose the views of HyrtI, but meanwhile Beraud had found that anastomoses exist between the coronary arteries and vessels from adjoining organs. Pamfm, von Bezold and Brevmann and later Samuelson again experimented with dogs and were able to confirm Erich- sen's conclusions. In [880 Langer showed that anastomoses exist between 80 THE BLOOD SUPPLY TO THE HEART the coronary arteries and those of the pericardium and, through these, with the arteriae mammariae internae. He showed further that by means of the vasa vasorum of the pulmonary artery, connection also takes place with the bronchial arteries and, through branches from the auricles, with the diaphragm. In 1881 Cohnheim and A. von Schulthess-Reehberg reported their experiments on the clamping of coronary arteries in curarizcd dogs. Their conclusions, which profoundly in- fluenced the opinion of future observers and which are still being held by some, were, that clamping of either mam coro- nary artery caused the ventricles to stop in diastole within two minutes. They accordingly argued that the coronaries were end-arteries, and that, if any anastomoses exist, they must consist of fine capillaries. This was later confirmed by G. See, Bochefontaine and Roussy, Bettelheim and Kronecker. The ligature experiments thus far made, together with injections carried out by DragnefF, Zimmerl and Banchi which again confirmed Hyrtl's work, helped to lend much support to the opposers of the view that anastomoses exist. It was not long, however, before a great many observers, notably McWilliam, Fenoglio and Droguell, Bickel, Roister, Tigerstedt, von Frey and Porter, after performing very care- fully numerous ligation experiments in dogs, came to conclusions opposed to those of Cohnheim and von Schulthess- Reehberg. In general, they held that many of the Iatter's results were due to the trauma of the operation, and that tying-ofl branches and even a main coronary artery does not necessarily lead to instantaneous death. In i8<)2 Roister gave an accurate description of the processes of infarct forma- tion and healing by scarring. THE CORONARY ARTERIES 81 This opposition, moreover, further gained strength by the collection and description <>l numerous clinical cases and pathological material by Samuelson, Huber, Aschofl and Tawara, Huchard, West, Chiari, Pagenstecher, Engclhardt, Thorel, Dock, Galli, Merkel, Osier, Krehl and, recently, Herrick. These observers were able to show that in the human heart, obliteration of coronary branches, and in some cases a main coronary artery, produced results which varied in the different cases from almost instantaneous death to those which experienced no symptoms and showed absolutely no clinical sign, the condition being recognized only at post-mortem examination following death from some intercurrent disease. Some of these observers, too, were able to make out by dis- sections distinct anastomoses. It now remained to describe exactly the location and appearance of these anastomoses and to explain why, il anastomoses exist, infarcts occur. In 1907 Jamin and Merkel elaborated and improved on Freyctt's method of radiographing injected coronary arteries and presented a stereoscopic radiographic study of 29 hearts whose coronary arteries were injected with a 10 to 15 per cent suspension of red lead in gelatine. They concluded that great individual differences exist in the anastomoses and that these are found most frequently in the auricle, interauricular and interventricular septum and, in special instances, on the anterior wall ol the right ventricle, oxer the papillary muscles and the ape.x of the heart. In pathological specimens, the anastomoses wire found especially in the interventricular septum and the anterior wall of the left ventricle. In tin' same year Spaltchol/ employed a chromc-\ ellow suspension in gelatine for injections with subsequent dclndra- 82 THE BLOOD SUPPLY TO THE HEART tion and clearing in benzol and carbon disulphide. By this method he was able to obtain a reconstruction of the cardiac circulation which, on the whole, was vastly superior to any- thing hitherto obtained. Spalteholz's conclusions are as follows: (a) No end-arteries exist in the heart. (b) Rich anastomoses occur in all layers of the heart and, through the vasa vasorum, on the great vessels. (c) In the thick muscle of the [eft ventricle, perpendicular vessels penetrate to anastomose under the endocardium. (d) The papillary muscles are particularly rich in anastomoses. (e) With growth, the appearance of vessels on the surface show a typical alteration. I lit sch performed a series of experiments on dogs in which he tied off the ramus descendens anterior and observed in- farct formation. In all normal cases, however, he found that the infarcted region was much smaller than the area of supply of the tied-oll vessel. In one instance where the animal had previously lost much blood, the infarcted area corresponded with the entire musculature supplied by the vessel. A similar observation had already been made on the human heart by von Recklinghausen and Fujinami. In 1909 Miller and Matthews were able to prove that many of the fatal results obtained by Cohnheim, Fenoglio and Droguell, Porter, etc., were due to the usage of curare and morphia. By using ether as an anesthetic and employing strophanthus as a heart tonic, they obtained a mortality of only 8.7 per cent after ligation of the ramus descendens anterior of the left coronary artery. Even after tying off a main branch of the ramus descendens anterior, the animal would recover for a period varying from one to three months and ultimately die of acute cardiac decompensation. They THE CORONARY ARTERIES 83 were, therefore, of the opinion that considerable anastomoses exist between both coronary arteries. In 1910 Amenomiya made a study of the blood supply to the papillary muscle and found only capillary anastomoses. In 1911 Nussbaum described direct connections between arteries and veins, made up of a single layer of endothelium possessing no muscular coats and lying in the subendocardium. He considered these as safety outlets for arterial blood when the pressure becomes too high. In Herrick's clinical classification of angina pectoris I 1012) one group of cases concerns patients who survived an obliteration of a coronary artery lor a period ol time which varied from days to weeks. All these occurred in individuals over fifty years of age. He was of the opinion that anastomoses exist and that the condition of the heart musculature and patency of the vessels played an important part in determining the degree of compensation which can take place after obliter- ation. Gradual obliteration, he argued, allows the heart to adapt itself to the new conditions and allows collaterals to develop sufficiently to compensate. He suggested that the \essels of Thebesius might serve as accessory nutritive chan- nels in such cases. Finally, very recently Smith made an experimental study on the question as to the existence of anastomoses. By observa- tion on dogs, as well as interpretations of human material, he concluded lor the following reasons that anastomoses exist: (a) Survival of dogs even after tying-off a relatively large vessel. (b) Variability of the lesion. ic) Relatively small size of the lesion. Thus, it cannot any longer be doubted that anastomoses exist between the branches of an individual coronarj artery as 84 THE BLOOD SUPPLY TO THE HEART well as between branches from both sides. The dissections of Thebesius, Haller, Morgagni, de Senac and Caldani, the experi- mental work by McWilliam, Fenoglio and Droguell, Bickel, Kolster, Samuelson, Tigerstedt, von Frey, Porter, Miller and Matthews and Smith ; the clinical and anatomical obser- vations made by Samuelson, Huber, Aschoff and Tawara, Huchard, West, Chiari, Pagenstecher, Engelhardt, Thorel, Dock, Galli, Merkel, Osier, Krehl and Herrick, as well as the injection work of Jamin and Merkel, Spalteholz and Nussbaum have placed this conclusion beyond dispute. There is still, however, no accurate knowledge of the exact nature as well as architectural arrangement of these anasto- moses. The author has accordingly made a very careful study of this question by the methods described in the chapter on technique and has come to the general conclusion that the heart is perhaps the richest organ in the body as regards capillary and precapillary anastomoses between branches of the same coronary artery as well as between branches from both coronaries. The detailed architectural description has been left to this chapter since it represents a category in itself. Figure 24 shows a photograph of an injected and cleared specimen which illustrates beyond any dispute the abundant network of anastomoses at the root of the pulmonary artery. A constant arterial arch is found crossing the first part of the root. It corresponds to the venous arch seen in this locality. The first part of the aorta shows similarly extensive anasto- moses between the vasa vasorum which arise from each coronary artery. On the surface of the heart (Figs. 14 and 14 A) agood injec- tion will show a very open anastomosis occurring between branches from the ramus descendens anterior of the left coro- THE CORONARY ARTERIES 85 narv artery and those- from the rami anteriores oi the right. A similar, though usually less conspicuous, anastomosis occurs on the corresponding posterior surface between the rami marginis obtusi and the rami ventriculares sinistn posteriores oi the right coronary artery. The interauricular and particularly the interventricular septum is the seat of very extensive and, in certain age periods (Chapter VI II), very wide anastomoses. So far as communication between smaller vessels ol the heart is concerned, the auricular walls and appendages, as well as the ventricular walls throughout, are the scat ol \er\ abundant anastomoses and interanastomoses between branches from both coronaries as well as between branches from each coronary artery. To this may also be added the anastomoses which occur between the vessels which supply (when this occurs) the valve leaflets (Fig. 13). Figure 5 shows the \cr\ complex and complete anastomosis of small \csscls, which takes place beneath the endocardium ol the ventricular walls and papillar muscles and within the musculature of the latter. Capillary anastomosis are \ cr\ numerous and rich and can be seen in any portion of cardiac musculature. Finally, an important factor in anastomoses and one u Inch, as will be seen in Chapter VIII, assumes, particularly in the later age periods, considerable functional significance, is that which occurs between the arteriae telae adiposae cordis, those \cssrls which lie in the fatty tissue under the visceral pericar- dium. The author has traced these vessels into the auricular as well as ventricular musculature and has found distinct anasto- moses between these- and branches from the coronarj arteries and \ asa \ asorum. Fig. 14 A. — An enlargement from Fig. i„ 86 Fig. 14. — Photograph of injected and cleared specimen, showing the anastomoses on the anterior surface of the heart. 87 THE CORONARY ARTERIES 89 Lastly, the author has found distinct connections between the coronary arteries and the vessels in the parietal pericar- dium, so that this, together with Langer's observations as to the existence of anastomoses between the corollaries and branches of the bronchial arteries, arteriae mammanae internae and those of the diaphragm, render beyond dispute the fact that distinct connections exist between the cardiac vasculature and that of the adjacent organs. If one now turns back to the first questions with which the discussion on this chapter was opened, it is found that the following statements can safely be made: (a) Anastomoses exist between the right and left coronary art (.-ries both in their capillary as well as precapillary distribution. (6) Anastomoses exist between the branches of each coronary artery. (c) Anastomoses exist between the coronary arteries and vessels from the adjacent and attached organs. (d) Anastomosis in the heart are universal and abundant. The question which now arises is how to explain, on this basis, the formation of infarcts, for it has been show n that end- arteries, in the anatomical sense of Cohnheim, do not exist in the heart. Pratt has formulated a definition in which he includes, m the category of junctional end-arteries, that vascular structure in which the resistance in the anastomotic area is greater than the pressure in the different vessels. To a certain extent only do the anastomoses of the heart fall under this definition. It has been stated that Ilirsch found in his experimental work on dogs, and this has been confirmed by von Recklinghausen and Fujinami as true for the human heart, that in normal 9 o THE BLOOD SUPPLY TO THE HEART hearts the infarcted area is smaller than that supplied by the obliterated vessel. When, however, the pressure in the blood is lowered or perhaps when the blood is rendered poorer in its composition, the infarct corresponds completely to the area supplied by the vessel. This occurred in one dog upon which Hirsch experimented. Hirsch concluded from these experiments that infarcts can occur in the heart, despite the anastomoses, because the heart is always functioning. He believes further, that the direction and extent of the anastomoses, the structure of the vessels, the heart strength and the time and duration ol the obliteration are important factors in this connection. Amenomiya concluded from his study of infarcts occurring in papillary muscles that for an infarct to occur it is necessary to have: (a) Too little anastomoses. (6) Closure of relatively large vessels. (c) Rapid blockage of the vessel. It is generally the case that the infarcted area is situated on the inner aspect of the heart (Smith, Oppenheimer and Rothschild), but it is occasionally found that the infarct occurs in the outer side of the wall, leaving the inner surface intact. This variability suggests that either other factors besides the anatomical construction can dictate the occurrence or non- occurrence of infarcts, or that the anatomical structure is fluid, or both. Spalteholz, Galli and the author (Chapter VII 1) have found cases where complete and almost complete obliteration of a coronary artery have produced no lesion in the myocardium. The age of the individual is of prime importance in this connection, for as will later be shown, the older the individual. THE CORONARY ARTERIES 91 the more free and patent are the anastomoses. An old heart, is therefore much more prepared to receive with relatively little or no damage, the brunt of a sudden obliteration of a nutrient vessel. Moreover, as Herrick has stated, a gradual obliteration of a vessel allows time for the existing anastomoses to widen and compensations to take place. Here the arteriae telae adiposae are of considerable importance, more especially in the heart of older individuals. The occurrence of an infarct on the outer rather than on the inner aspect of the heart, as in a case shown to the author by Dr. Rothschild, was undoubtedly due to the fact that here the subendocardial anastomoses were rich enough to supply the anemic area. If the foregoing facts, therefore, are summed up, it can be concluded that in the ordinary course of events and in the average young adult's heart, the intricate systems of anas- tomoses are all in active function and are not prepared to act suddenly as entirely adequate compensatory agents. Never- theless, when vascular obliteration takes place, a certain amount of compensation does occur, so that the infarcted area is smaller than the region supplied by the obliterated vessel, the remaining portion receiving sufficient nutrition from the anastomoses. Moreover, if the obliteration is gradual and the circulation good, sufficient dilatation of the anastomos- ing vessels can occur to preserve considerable, if not all, ol the musculature. When the obliteration occurs in a relatively older individual's heart, the patent and free anastomoses, as well as the well-developed arteriae telae adiposae, can often amply supply the affected area so that the myocardium can be completely spared. 9 2 THE BLOOD SUPPLY TO THE HEART Thus, it is seen that in the determination of infarct forma- tion, besides the factors of size of the obliterated vessel, its location, the duration and rapidity of the obliteration, the condition of the general circulation and that of the heart musculature, another very important one must be added — namely, the age of the individual. Chapter VII The Veins of the Heart ON account of their rather complicated embryo- genetic development, the veins of the heart are prone to considerable variation. As in the case of the arteries, a description will here be given of the venous structure in the average heart (Fig. 15) and this w ill be followed by a short discussion on the variations. To render the latter somewhat more comprehensible, a brief description of the embryogenesis of the heart veins will precede the description of the variations. The veins of the heart can be divided conveniently into: (A) Venae magnae cordis. (B) Venae parvae cordis. (C) Venae minimae Thebesii. A. VENAE MAGNAE CORDIS The term Venae magnae cordis has been chosen as a convenient category lor the largest veins ol the heart. This must not be confused with the \ esse! which encircles the left auriculo\ (.'Utricular furrow to empt\ into the sinus coronarius and which is called by some vena magna cordis. The author feels that the term Vena coronaria sinistra is much more suitable for the latter, and one less open to contusion. Sinus coronarius. The first great vein which is to be considered is the Sinus coronarius. It really serves largely as a collecting receptacle lor blood poured into it from the l >3 THE BLOOD SUPPLY TO THE HEART eins of the heart, and which it in turn - T:its to the right auricle. There has been considerable dispute as to whether the ...s coTonarius should include only that portion of the rly which is covered by musculature Reid, Marshall 1 or extend beyond this to limits defined by various . Cruveilhier). As Tandler points sis if Marshall's embryogenetic classification, - ~ >ry boundaries are the valvula Thebesii ".d the val seuii distally. It is usually nded in its entire course by heart musculature. ronarhis thus delimited lies in the po-" auriculoventricular groove and extends, usually as a short •. trunk covered with transverse musculature, from a nt halfway between the margo obtusus and the crux, si 1 the left of the crux. Vena coronaria cordis sinistra. Opening directly into the nanus through the valvula vieusenii and continuous I is the Vena coronaria cordis sinistra. This is a large I pers from - gin as the continuation of the aris anterior at the junction of the auriculo- tricular sulcus _ . _ as it rounds the margo " • - in the furr I Dome eventually continuous with the sinus coronarius. \ cna mterventricularis anterior. This vein commences usually at the lower third of the anterior interventricular .1 wide anastomosis with the corresponding posterior vein. It ascends the sulcus in company with the ramus de- scendens anterior of the left coronary artery and, at the entricular sulcus, becomes continuous with the vena coronaria cordis sinistra. Fig. 15. — Roentgenogram of the venous distribution in the average heart. 95 THE VEINS OF THE HEART 97 Vena coronaria dextra. Another constant vein which opens into the sinus coronarius, is the Vena coronaria dextra. This vein is rather slender, lies in the auriculoventricular furrow in the right posterior aspect ol the heart and is often the direct continuation ol the vena marginis acuti. \ ena marginis acuti. This smaller vein commences on the lower third of the margo acutus as a distinct anastomosis with one of the terminal branches of the \ ena intcrventric- ularis posterior. It rounds the junction of the margo acutus with the auriculoventricular sulcus to become the vena coro- naria dextra. As will later be shown, it may also open inde- pendently into the right auricle. Vena interventriculars posterior. This [arge and tapering vein commences in the lower third ol the anterior interven- tricular sulcus. Anastomosing at its origin with the vena interventricularis anterior, and receiving anastomotic twigs from the vena marginis acuti and venae marginis obtusi, it rounds the apex and ascends the posterior interventricular sulcus to empty into the sinus coronarius. Branches \\ bicb Enter the Venae Magnae Cordis Vena obliqua atrii sinistri (Marshalli). Because it is of considerable embryogenetic interest and marks as well at its entrance the beginning ol the sinus coronarius, the delicate auricular vein known as the \ ena obliqua atrii sinistri merits Inst description. This vein commences on the anterior Surface ol the lelt auricle and, proceeding between the two left pulmonarj veins, courses diagonally downward and toward the right ol the heart to empty into the sinus coronarius about the site ol the \al\ula \ icusenii. Venae ventriculi sinistri. These are verj large veins which, 98 THE BLOOD SUPPLY TO THE HEART on the left side, carry blood centripetally from a point two- thirds down the margo obtusus as the center, to empty into the venous ring formed by the linking up of vena coronaria cordis sinistra, vena interventricularis anterior and vena interventricularis posterior. According to their situation they are called Venae ven- triculi sinistri posteriores, marginales or anteriores. Venae ventriculi dextri. On the right side, the venous chain is not so large and consists of the linking up of vena marginis acuti, vena coronaria dextra and vena interventric- ularis posterior. Into this ring there course centripetally and empty, veins which are not so large as those found on the left side. These are known on the posterior surface of the right ventricle as Venae ventriculi dextri posteriores. Here they usually pursue a remarkably even horizontal course, parallel one to the other. Finally, in the interventricular septum there are found numerous, large and richly interanastomosing veins which empty into the anterior and posterior venae interventriculares. The topmost of these empties into the vena interventri- cularis posterior. It accompanies the ramus septi fibrosi through the bundle and shows a wide anastomosis with a more delicate vessel which empties into the vena interventricularis anterior. There remains the description of the veins draining the anterior surface of the right ventricle. This is accomplished by two systems: (i) venae ventriculi dextri anteriores; (2) venae parvae cordis. The Venae ventriculi dextri anteriores are transverse richly anastomosing veins which empty into the vena marginis and vena interventricularis anterior. THE VEINS OF THE HEART 99 B. VENAE PARVAE CORDIS It will be seen that the auriculoventricular sulcus is sur- rounded by veins in its whole circumference with the exception of that part which lies between the margo acutus and anterior interventricular sulcus. It is over this portion of the sulcus that the second group of veins, draining the anterior surface of the right ventricle, cross to empty directly into the right auricle. These consist of three or four relatively small veins which run parallel to one another and show wide anastomoses in their ventricular aspect. Two other venae parvae cordis deserve some special men- tion. One, which empties into the right auricle between the root of the pulmonary artery and the appendage, corre- sponds to the constant arterial arch already described at the junction of the conus with the pulmonary artery (Cru- veilhier) and anastomoses with a corresponding vessel which empties into the right auricle alter draining blood from the roots of the aorta and pulmonary artery and adjacent portion of the right auricle ( Zuckerkandl). For the rest, a number of small auricular veins which empty for the most part into the vena coronaria sinistra and which show some correspondence with the auricular arteries, constitute the remaining venae parvae cordis. Of the veins thus far described, the main trunks usually accompany branches of the coronary arteries and, in these eases, occupy a position beside them or lying upon them. The smaller ramifications may lie subjacent to the arteries. The deeper divisions of the veins differ from the arteries in that they do not form so regular a series of dichotomous branching ioo THE BLOOD SUPPLY TO THE HEART but course to the surface as somewhat tortuous, delicate, interlinking channels which join up at the surface and abruptly empty into the larger superficial trunks of the second and third order. At the apex, there is often seen a well-formed medusa- head whorl of delicate veins which empty into the terminal branches of the venae interventricularis anterior and posterior. At the root of the aorta and in the subpcricardial fat, a well formed structure of venae telae adiposae can also be formed. C. VENAE MINIMAE THEBESI I It has been seen that with the exception of the vena obliquaatrii sinistri and the vein described by Zuckerkandl, there are practically no veins of larger, caliber draining the auricles. This lack is largely made up for by the existence of tiny venous channels known as Venae Thebesii according to their discoverer Thebesius, who described them independently and unaware of the fact that Vieussens had already made known their presence. Their existence has been open to much discussion, having been confirmed by Winslow, Verheyen, Lancisius, Bochdalek, Henle, Hyrtl and others, and denied by Senac, Zinn, Haller, Cruveilhier, Theile and Luschka. Bochdalek, moreover, proved their existence in both auricles and this was later confirmed by Langer. Those who denied the existence of these tiny channels as carriers of venous blood, held them to be blind diverticulae. Haller claimed that their function as veins meant admixture of venous blood with the arterial on the left side, which seemed improbable on physiological grounds. The openings of these channels, known as Foramina Thel>esn are, however, very easily seen, particularly in the THE VEINS OF THE HEART 101 auricles. That they communicate with the general venous system can readily be proved by injections. These experiments have been successfully carried out by Thcbcsius, Langer, and the author. Recently, the existence of venae Thebesii in the ventricles has been proved in a similar manner. This, however, has been denied by Nussbaum. These vessels can be divided into two types: (a) With \er\ small openings, 1-2 mm. in width, which drain the capillaries in the auricles; (/>) with larger openings, in which several sec- ondary openings can be seen, and which link up with large venous channels m the musculature and on the surface ol the heart. The venae minimae Thebesii are very numerous in the right auricles, being seen in greatest numbers in the interauric- ular septum, especially in the region of the hmbus Vieussenii and valvula Thebesii. In the left auricle they are not so numer- ous, but generally larger. Thus, Langer has shown that, on the interauricular septum adjacent to the aortic valves, cer- tain larger venous openings can be found which dram as well in part the superior portion of the interventricular septum. It is possible that into the category of veins fall also the long grooves described by Lannelongue. II one ol these is injected, the injection mass is forced out of the adjoining groove. Tandler does not feel that he can confirm with cer- tainty Lannelongue' s statement that these grooves drain small \ enous channels. In the ventricles, foramina rhebesii are most frequent at the liases ol the papillarx muscles, the region of the (.'onus on the right side, and, according to Langer, the apical mus- culature. 1 hex do not hert- communicate directlj with the larger veins except possibly through capillary anastomoses. io2 THE BLOOD SUPPLY TO THE HEART and appear to be concerned more with draining the subendo- cardial spaces and the immediately adjacent musculature. VARIATIONS IN THE VEINS OF THE HEART As has already been stated, the venous structure of the heart is very liable to variations. Some of the more outstand- ing and interesting variations can easily be explained on an embryological basis. Very early in embryonic life, the anterior and posterior cardinal veins link up to form the ductus Cuvieri, and these in turn open separately into the heart. Normally, only the right opening persists and this is made possible by the develop- ment of a great anastomosis between the anterior cardinal veins, which enables the left vein to conduct all its blood into the right auricle. The lower portion of the right anterior cardinal vein and the right ductus Cuvieri become the vena cava superior of the right side. The corresponding structure on the left side, as has been shown by Marshall, regresses so that only vestiges remain of the greater part of the left superior vena cava — namely, the vena obliqua atrii sinistri and the plica venae cavae; only the proximal portion of the left ductus Cuvieri is preserved as the sinus coronarius. When the opening of the coronary sinus into the right auricle is obliterated, blood is carried through a persistent left superior vena cava into the vena innominata. This oblitera- tion, as Siding has shown, must occur necessarily in the second month of embryonic life and at a time after the formation of the vena innominata. Tandler cites 2 cases, that of Le Cat (1738) and that of A. Siding (1896), where this condition occurred. Here the sinus coronarius commences as a trunk which runs obliquely THE VEINS OF THE HEART 103 over the posterior wall of the left auricle in front of the left pulmonary veins, through the Iigamentum venae cavae to reach and empty into the vena innominata. The opening of the sinus coronarius into the right auricle is obliterated. Extending out from the right auricles, through an opening flanked by a low valvula Thebesii, is a blind sac about 10 mm. in length and representing the proximal portion of the sinus coronarius. The patent portion of the sinus coronarius, which continues up towards the pulmonary veins, receives the entrance of the vena coronaria sinistra and the vena interventricularis poste- rior through openings guarded by valves. The above described condition is infrequent but deserves special mention on account of its interesting genesis. A frequent variation and, according to Piquand who found it in 20 per cent of the cases, representing the primitive form, is the entrance of both vena coronaria sinistra and vena interventricularis posterior by a common short channel, the truncus communis. In a number of hearts, the vena marginis acuti empties independently into the right auricle and is then called the Vena Galeni. The vena coronaria dextra frequently varies in its site in the auriculoventricular groove, being often found lying above this in the auricular musculature. Not infrequently a stout vena marginis obtusi ascends the surface of the ventricle and, curving parallel with the vena coronaria sinistra, opens independently into the sinus coronarius. The venae minimae Thebesii are liable to much variation in their size, form and situation. So far as structure is concerned, it has already been stated io 4 THE BLOOD SUPPLY TO THE HEART that the sinus coronarius is usually surrounded by transverse muscular fibers from its origin to its conclusion at the valvula Vieussenii. The musculature may fall short of the valves but never, according to Tandler, passes beyond them. Chapter VIII Age Period Changes in the Blood Supply to the Heart \\i> their Pathogenetic Relations IN introducing the discussion on the age period changes which the blood supply to the heart undergoes, it may be permissible to quote, slightly modified, from the author's article on the postnatal evolution ol the spleen, in order to make clear the general importance ol the subject: Various integral parts of the human organism die long before the whole organism is born. Birth and growth of new tissues continue long alter the whole organism is bom. Life, in fact, consists of the simultaneous breaking down and building up ol protoplasm, cells, tissues and organs. I mbryonic development presents some of these phenomena in striking, almost dramatic, form. Moreover, it appears that these processes display, at least m some instances, a coordinated relationship. Oertel was the first to show that tin- development and growth ol the sex gland in the embryo is definitelj correlated with the degeneration ol the mesonephros, and thus gave an actual anatomic foundation to the idea that the relationship of cells, tissues and organs is by no means always altruistic, but, as held many years ago l>\ Boll, Roux, Hansemann and Others, often antagonistic. Life and evolution ol the individual, like hie and evolution ol an\ community, depend not only upon hoi pi n I but also upon opposing forces, rhese phenomena ol embryonic life possess an additional interest to the pathologist because almost all pathological processes, degenerations, inflammations and even tumor growth, are. as Minol pointed out years ago, in principle and prototype to be found in the normal embryo. In postnatal hie, the appreciation of the unstable and constant l\ changing character of cells, tissues and organs has in recent years been somewhat more lulb recorded especially since their pathogenetic importance has become clear. Thus, 106 THE BLOOD SUPPLY TO THE HEART since Reid's observations on the measurements of the heart and tables on the weight of the most important organs of the body at the different age periods appeared in 1843, several other important contributions on different organs have helped to show that these changes represent a general principle of life. In 1883 Miiller presented his observations on the weights and measurements on the heart and its structures, and though he did not particularly stress the age period idea, his carefully compiled statistics based on a very large number of hearts furnish, as will be shown later in the discussion, a great number of very interesting points. It may be well, however, to outline here, first, the present knowledge regarding postnatal development in other organs of the body, thus showing the significance of age period changes and of the fluid state of tissue. In 1904, Reitmann pointed out that the normal pancreas is, from infancy to old age, a very unstable organ. Degeneration, atrophy, cell loss and acinar collapse are, to a certain extent, normal performances, being almost simultaneously com- pensated for by formation of new cells, new acini and, in the growing, youthful pancreas, even by the formation of new lobules. Coplin found equally great instability in the thymus, Theilhaber in the endometrium, and Milne in the ductless glands, chiefly the thyroid and suprarenal gland. In 1909, Herxheimer called attention to the frequent occurrence of hyaline glomeruli in the kidneys of infants and young children. These, Oertel regards as remnants of reduced and regressing renal substance similar to those found in other- wise healthy adult kidneys without arterial disease. Oertel, and Oertel and Anderson, have more recently been AGE PERIOD CHANGES IN THE BLOOD SUPPLY 107 able to corroborate and to extend Reitmann's observations on the pancreas and to show further that certain localized re- stricted abnormalities or faulty reconstructions may even nor- mally be found, making it at times difficult to define on which side of the borderline between physiologieal and pathological they may be classified. Thus also the condition which Oertel has called "Essential Atrophy of the Pancreas" appears, as he states, to represent a pathological exaggeration of, and loss of balance in, normal, physiological processes of regression and progression which are constantly going on in the pancreas. In his studies on degeneration, senescence and new growth, Oertel has further drawn attention to the close interrelation between these normally occurring processes and distinct pathological conditions. Somewhat similar observations have been made by Rene Sand in a study of pathological senescence. In i()K), the author was able to add the spleen to the already growing list of organs showing a distinct cycle of progressive and retrogressive processes during the age periods, and pointed out that age has a most important bearing both as regards the anatomical structure of the spleen in health, as well as to the reaction which it presents in disease. In U)2o, Waugh came to similar conclusions on the bone- marrow and this was soon followed by Weed, whose studies convinced him that very definite qualitative structural modi- fications occur in the pia arachnoid in advanced age periods, notably in the appearance of newly formed endothelial cell clusters, etc. Finally in 1921 Oertel summed up the existing tacts on postnatal evolutions and pathological organ reconstruction in its relation to function and disease and came to the following conclusions: io8 THE BLOOD SUPPLY TO THE HEART (i) Organs which normally exhibit a developmental cycle of changes in cell elements and tissue organization, undergo corresponding functional modifications. Pathological, anatomical and functional changes must, therefore, be interpreted in conformity and comparison with an age period. (2) Disposition to disease is influenced by structural alterations in tissue soil in the various age periods, especially in affording or not affording anchoring ground for bacteria. Moreover, it is likely that the fluid con- dition of organs influences the disposition to infections during waves of regression and progression as we already know it in unbalanced, juvenile and growing tissues. (3) Anatomical and functional expressions of a disease vary in one and the same organ according to its construction and composition during an age period, and it would seem that these factors also exert an influence on variations in disposition and immunity. (The author has shown this to be true in endocarditis, and Lexer in osteomyelitis.) (4) Diseases may arise from the fluid and changing state and age progress of organs by loss of balance in physiological regression and progression. (5) Depending upon the pathological predominance of one or the other group of changes, essential atrophies, hypertrophies, degenerations and progressive, destructive cell proliferation, all of which are normal developmental processes, may be duplicated and exaggerated in post- natal existence. Thus, Oertel has elevated the importance of postnatal age period changes to a general biological principle upon which depends the evolution of the individual from birth to senility and the development of disease. One is now in a better position to appreciate similar changes in the heart, for the vascular architecture of the heart shows strikingly the remarkable effect of age periods in pro- ducing a cycle of events which register unmistakably their effects on (unction, both physiologically and pathologically. Moreover, these changes occur not only in the absolute sense, but also, as will be seen, in the relative constitution and construction of both sides of the heart. AGE PERIOD CHANGES IN THE BLOOD SUPPLY 109 Bizot has shown long ago that in the embryo both ventri- cles arc about the sanu- thickness; at birth tin- left is slightly thicker, and, after this, outstrips the right in growth so that it gradual!} becomes relatively more and more preponderant. 15i 2-° 3 s - 4 T -* J- 6 T -= 7^ 6- 9- B1RTH DECADE DBCADE DECADE DECADE DECADE DECADE DECADE DECADE DECADE 70pM 00 •• m ■• 40 •■ 50 •• 20 ■• 10 - » Fig. 16. — Graph showing the increase "I subpericardial fatty tissue as age ,i\ then figures THE BLOOD SUPPLY TO THE HEART there is an undoubted relatively greater increase on the left side, which reverses in the later decades of life. Miiller ( 1 877-1881) made a study of 1,481 hearts. From observations on their gross weight he concluded that the turning point in growth of the heart is in the seventh decade in men and the eighth decade in women. Though he held that there is a relative proportion between the amount of subpericardial and subcutaneous fat, his figures show a distinct and gradual increase in the former from birth to death. Figure 16 shows this process graphically in a chart which the author has plotted out from Midler's statistics. A study of his figures on the comparison of the weight of the right and left auricle, in regard to age periods, shows that, on the whole, there is very little difference between the two. His figures expressed in units of proportion (Table VIII) are as follows: TABLE VIII Male Female Age Embryos 1 Month 2-12 Months. 2- 1 5 Years . . . 16-20 Years. . 21-80 Years. . Right auricle i-7 1.6 1-7 1-7 Left auricle > 5 i-5 1.7 1.6 1.6 1.7 Right auricle Left auricle [.4 ■4 .6 •7 6 ■ 7 From these he draws the following conclusions: (a) The division of the auricular musculature of both auricles is different before and after birth. During the whole embryonic life, the muscle mass preponderates in the right auricle. During the first month after birth, the right auricle loses in weight. At the beginning of the second month, both are similar in weight. This equality more or less persists during the first year. (b) From the second year of life until the period of maturation of sex, the left auricle preponderates, after which the right again preponderates. AGE PERIOD CHANGES IN THE BLOOD SUPPLY 1 1 1 Much more interesting and important in are his figures comparing the mass of the right cles according to age periods (Table IX). TABLE IX this connection and left ventri- Male Female Age No. 1 of R. cases | - :.. No. of | R. cases 1 L. R. L. Embryos i 500 gms. 10 42 $6|o 845 6 0.37 39 -31 50 1 1 000 gms 9 I ii3 I. I7I0.769 7 | 1.29 1 . 40 -10 1 001-1500 gms 4 \ 2 3^ 2.04 S42 10 1 2.45 2. 28 0.811 1 501 2"00 gms 11 341 3.06 864 ii 3 . 06 2.59 0.902 2001-2,00 gms. 6 4 31 4.04I0.85 6 398 4 .i8|o 786 2501 5000 miis 6 6 02 4.84 925 - 5 46 4 020.849 over 3000 gms 15 7. 72 5 44 1 007 7 | " 14 4 69 1 065 1 week post-natal 16 | 4.85 4 4,-0 839 17 | 3-82 3.47I0.827 2 weeks 13 I 4-H 4.79I0.698 15 | 4. 10 4 53 -33 10 | 4. 10 4.93I0.680 5 4.04 5.040.678 5 4 1 ' 5 83 635 10 3 44 4. -10. 638 14 5 09 4 54I0.594 14 3 43 5.42I0.571 3 months 14 3 "4 6.44I0.561 16 | 3.88 6. J.1I0. «A« - ill ,22 24 4 68 - 000 ,-32 20 4 33 - 12 months 34 5 " 2 10 68 502 31 5. — 10 43:0.515 1- 00 14. no. 561 24 -.8213.520.525 13 in dj 23 — 469 10 9 04 18 200.4-3 17 |n.07 22.23 4"3 ■" 11 "i-i 94 0.499 16 1- 68 33. 080.48-! 21 14.3121.020 _l-i _i.fi- 8 24.20 44 . 4o|o. 50o|| Q 20.1040.90 23 46.00 -0000.542 13 39.10-3.800.508 1 1 30 \ears 69 ; i u 1 QO.50lo.5iol 46 1-. Qol-2. Qolo. .ton 67 -;o 8< 88. 9o|o. 529H 5- 3- -008.90 I 82 5 1 -< 04 (jo 500 '»j 45.20-5 200 552 *4 S4 ')' 101 6o|o ,-oS 58 43 3" "3 "oo 52(j 6i 70 3 ears 87 S5 n 103 70 i 10 S3 4(1 doNi 20 545 62 52 4c 94.40 526 6i 43 90 82. -0 yi 5 Si 1/0 \ (Mis 11 41.2c 97 20I0.442II 12 jo iolfifi 100 t88 ii2 THE BLOOD SUPPLY TO THE HEART Represented in chart form, the gradual and consistent, increasing, postnatal preponderance of the left over the right ventricle as age advances, is strikingly seen (Fig. 17). 3IRTH DECADE DECADE DECADE DECADE DECADE DECADE DECADE DECADE DECADE OOffe 90 •■ -— 1 80 •• 70- •■ 60 » 50 " 40 •• ^ 50 •• 20 " 10 •■ • LEFT VENTRICLE Kim VENTRICLE Fig. 17.— Graph showing the absolute increasing weight of the right and left ventricles as age advances, and also the relative increasing pre- ponderance of left over right side. Councilman has recently come to the conclusion that heart hypertrophy is very frequent in old people and regards it as pathological. Lewis has been able to confirm Einthoven's observations that before birth and for several months after, the heart shows electrocardiographically a right-sided preponderance which AGE PERIOD CHANGES IN THE BLOOD SUPPLY 113 soon, however, becomes equal and from then on becomes pre- ponderant in the left. Unfortunately, accurate comparative age period observations on this point arc wanting for the post- natal development of the heart, but Lewis and others have observed electrocardiographic curves in adults which speak for left-sided hypertrophy in apparently normal cases. In old individuals, relative preponderance of the left ventricle is a common observation. In consideration of all the foregoing facts, it is not sur- prising that the cardiac circulatory architecture shows a corresponding series of changes which, in their qualitative and quantitative nature, are of prime physiological and pathologi- cal importance. If one examines Figure 18, which represents a roentgeno- gram of the circulation in an a\ erage heart at birth, it isscen that both sides of the heart are equally divided and supplied with blood, so that, were it not lor the characteristic ramus cir- cumflexus dexter, one would be at a loss to discern the [eft from the right side. Examined stereoscopically, this heart lails to show macroscopic septal anastomoses. I he branches show a uniformity oi lumen, and are, with the exception ol their extremities, on the whole without tortuosity. Figure 10 is a photograph of injected and cleared specimens of hearts at birth. It will be seen that at this period of life no arteriae telae adiposae arc visible in the subpericardial hit, so that the aunculovcnt ricular sulci carry no fat-vessels, nor do these accompany the mam coronarj branches. Figure 20 represents an average heart of the Inst decade. In this roentgenogram the main branches pursue a straight and 1 \ en course. There is a beginning clearing of the right side. Septal anastomoses cannot yet be made out. This heart did not show, ii4 THE BLOOD SUPPLY TO THE HEART upon examination of the cleared specimen, any arteriae telae adiposae. In the second decade (Fig. 21), the distribution of blood is beginning to be a little more marked on the left side. The vessels have hardly commenced to show their tortuosity. The stereoscope, however, already reveals very delicate septal anastomoses. At the furrows, the cleared specimen shows a few stray fat-vessels, best seen as rami telae adiposae parallel to the main branches. The third decade of life (Fig. 22) shows a definite, though not yet marked, left-sided vascular preponderance. Septal anastomoses are now much more clearly made out. The tor- tuosity of the vessels is quite discernible and, in the cleared specimen, rami telae adiposae are well seen. The fourth decade of life presents these changes in definite progress (Fig. 23). The septal anastomoses are quite clearly developed. The left side of the heart is definitely in the ascend- ant. Tortuosity of vessels is clearly seen and becoming marked. Figure 24 is a photograph of an average injected and cleared heart from this decade. It shows the already well- developed fat-vascular system. It will be seen that the anterior surface of the heart displays in the auriculoventricular groove a striking network of delicate arteriae telae adiposae. At the edges of the heart these are seen projecting from the surface into the subpericardial fat. The parallel fat-vessels can quite easily be made out as they accompany the main branches, particularly the ramus descendens anterior. Figure 25 shows the posterior surface oi the same heart. Here, there is displayed even better, the well-developed net- work of arteriae telae adiposae. It fills the whole auriculo- ventricular groove and appears as a greyish maze of vascular Fie. 18. — Roentgenogram oi'tlie blood supply in the average heart at birth. Fig. 19. -Photograph of injected and cleared specimen, showing the super- ficial distribution of the coronary arteries at birth. 1 '5 I V I [G 20. — Roentiii 1 ram "I the blood supply in the average heart ol the first decade. 117 Fig. 21. — -Roentgenogram of the blood supply in the average heart of the second decade. 119 Fig. 22. Roentgenogram of the blood supply in the average heart ol the third decade. r~*t *? Vi Fig. 23. — Roentgenogram of the blood supply in the average heart ol the fourth decade. '23 Fig. 24. — Photograph of t he anterior surface of an injected and cleared heart of the fourth decade, showing the distribution of the arteriae telae adiposae. Fig. 2j. — Photograph of the posterior surface of the same heart as in Fig 24, showing tlu- distribution of the arteriae telae adiposae. V *r j Fig. 26. Roentgenogram ol the blood supply in the average heart oi the fifth decade. 129 Fi ::. 2-.— Roentgenogram of the blood supply in the average heart of the sixth decade. vi^ Fig. 28. Roentgenogram of the blood supply in the average heart "I the >r\ enth decade. '33 9 Fig. K). — Roentgenogram of the blood supply in the average heart of the eighth decade. '3. AGE PERIOD CHANGES IN THE BLOOD SUPPLY 137 channels. Here too, the accompanying fat-vessels are clearly seen. In the fifth decade (Fig. 26) the preponderance oi left side o\ er right is striking, as is also the tortuosity of the vessels. At this period of life the main branches are occasionally seen fas thej are in this instance) projecting beyond the mass of heart musculature into the fat. This is due to a beginning regression and atrophy of heart muscle, leaving the vessels relatively too long. The septal anastomoses are distinct and abundant, being arranged somewhat in the fashion of a row of harp strings. In the cleared specimen, fat-vessels are quite well developed and numerous. The sixth deeade of life (Fig. 27) shows an ever increasing left-sided vascular preponderance and tortuosity of the vessels. The septum shows a system of very patent and free arterial anastomoses. The increase of the rami tela- adiposac is in keep- ing with the other changes. Figure 28 shows verj beautifully the stage of development of these four features in the seventh decade of life; the increas- ing relative anemia of the right side, the marked tortuosity oi the vessels, the rich and abundant septal anastomoses and, in the cleared specimen, the well-developed fat-vessel network. In the eighth decade of [ife another complicating feature appears. In a large percentage of cases arteriosclerotic chang< - are seen. This is well shown in Figure 29. Here the ramus cir- cumllexus dexter presents in its entire extent an unevenness of bore, and at its termination just before the ultimate branch- ing, a distinct aneurysmal bulging. Moreover, the left-sided vascular preponderance, the tortuosity, the rami telae adiposae and, in the stereoscopic plates (for this plate was taken at right angles with the direction of the septum, hence shows 138 THE BLOOD SUPPLY TO THE HEART anastomoses only upon stereoscopic examination), the septal anastomoses are seen to be distinctly on the increase. Figure 30 is a composite, representing the contrast between the circulation of the heart at birth and in the seventh decade of life. Here one sees exceedingly well illustrated the difference in the relative amounts (if blood supplying both sides of the heart, in the tortuosity of the vessels and the patency of the septal anastomoses. A comparison of Plates 19, 2j and 34 shows the progressive and consistent increase of the rami telae adiposae from birth to the fourth, and from this, to theeighth decade of life. Perhaps there is no better way of concretely establishing the importance of these changes in the postnatal evolution of the cardiac vasculature than by observing their effects upon function. Figure 31 is a roentgenogram of a heart from a female, aged seventy-three, who died of cancer of the gall-bladder. During life she had no symptoms referable to the heart or coronary vessels. In the hospital no signs were found during life indicat- ing a lesion of the heart. Upon injection of the heart at autopsy, however, it was seen that the ramus circumllexus dexter presented to a great extent of its course an arterio- sclerotic obliteration which was, in several places, almost complete. The myocardium was absolutely intact, no suggestion of an infarct being present. The case is, in short, very similar to that described by Galli. A more careful observation of the plate shows that a very ample and abundant anastomosis of large, patent rami interventriculares supplied, to a great extent, the right side, and this was further compensated by an extensive labyrinthine felt-work of rami telae adiposae which massively covered the right ventricular surface. (Fig. 32 Fie. jo. Roentgenogram oi th< bl I supply in the average In-art at birth and in the seventh decade, illustrating the marked evolutionary changes which the advancing age periods have produced. i 59 1 Fig. j _ _ ted heart, showing well-marked and almost complete teration of the Fig. ]i. -Photograph of injected and cleared specimen, showing the development of the rami telae adiposae on the right side of the heart, illustrated in Fig. 31. 143 Fig. $3. Microphotograph of a section through the arteriosclerotic vessel from the heart, illustrated in Iig. 31. 145 I h,. 54. Photograph of injected and cleared specimen, showing the rami telae adiposae on the left side of the heart, illustrated in Fig. 31. 14- AGE PERIOD CHANGES IN THE BLOOD SUPPLY 149 shows a photograph of this injected and cleared specimen. ) I hese fat-vessels were traced into the musculature and were found to anastomose with persistent right branches and with the compensating left ones. It will be observed in the roentgenogram that the ramus os1 ii ca\ at 1 superioris pursues an undisturbed course to the sino- auricular nude because the arteriosclerotic process commences i ust beyond the origin of the vessel from the right coronary artery. Figure 33 shows a microscopic section through one portion of the partialK obliterated artery. It is seen that extensive obliterating endarterial changes have left a few canalized areas through which the barium (black in the photograph) has forced its way. In other places the obliteration was even more marked. The conclusions which can be drawn from this case are, that in the seventh decade of life the vascular architecture of the heart is well prepared to receive the brunt of the oblitera- tion even of a main coronary artery, not only on account of the existence of abundant and free anastomoses, but also, as is seen in this cast, by the non-negligible factor of the development at this age period of a dense felt-work of arteriae telae adiposae which can compensate and supply considerable blood to the subjacent muscle. In fact, that the rami telae adiposae are able to increase in caliber and quantitj so as to furnish additional Mood, is seen In comparing figure 52 with Figure 34, (which represents the posterior surface of the same heart and shows a fat-vessel structure commensurate with this age period). This comparison shows that the increase of fat-vessels on the right side is out of all proportion to the normal development, but it must be remembered that this great increase is only i 5 o THE BLOOD SUPPLY TO THE HEART possible on a basis oi an already well-developed structure. Furthermore, in this particular case, the gradual obliteration allowed for an ample development of these compensating structures, so that the myocardium was left absolutely intact. There are all gradations of possibilities which lead up to this interesting case. It has already been shown in Chapter VI that the heart possesses in the anastomoses a structure which can and does give the heart considerable vascular reserve. This, moreover, as appears from our present discussion, becomes gradually more and more valuable for such a purpose as age advances, and since the heart presents at the same time a parallel increase of rami telae adiposae, a very potent ally, it acquires a compensating structure whose functional possi- bilities increase in direct proportion with age, that is, with that time of lite when pathological processes would make an increasing, more frequent and greater demand upon it. There is thus a definite functional significance in these progressive evolutionary changes. That the rami telae adiposae are an expression of a general body nutritional reserve structure would seem to be indicated by the fact that they have been found by the author in other organs which show a senile increase ol fat. Thus, for example, in the senile as well as in the contracted kidney, the very fatty pelvic contents possess a rich supply of arteriae telae adiposae. In the contracted kidney, they can distinctly be seen penetrating the pyramidal parenchyma and supplying it with blood. It appears then, that there is a definite reason tor the progressive increase of subpericardial fat as shown by Figure 1 6, made from Midler's figures, and that this serves as a carrier AGE PERIOD CHANGES IN THE BLOOD SUPPLY 1,1 lor a most important and apparently hitherto unrecognized functional and compensating unit. It cannot be argued that the development of fat-vessels is entirely secondary to functional need, lor it has already been shown that their increase is progressive and proportional to age, irrespective of the presence of a pathological lesion. It is true, however, that an obliteration of a coronary branch can bring about an added development and quantitative as well as qualitative changes in them. The increasing tortuosity of the vessels, a general expres- sion of increasing age, can be accounted for by the qualitative deterioration in the vascular wall and by a relative shrinkage and atrophy of the heart muscle in the later decades of life. There remains, therefore, only to explain the gradually developing relative right-sided anemia. It must be borne in mind, first of all, that this is to a great extent relative; the increasing Iclt-sidcd musculature and consequently vasculature overshadow that of the right side. Furthermore, the right ventricle perhaps does not so much present a regression of \ essels as a falling behind in circulatory development, so that it becomes relatively more and more anemic. \\ ithout doubt, these changes are of far-reaching functional significance. It is easy to comprehend why in embryonic life the right side, which is the more acti\el\ functioning one, should attain a greater development of its vascular tree. This persists for some time after birth, but with the assumption of greater acth ity b.\ the left ventricle, the latter becomes more and more richly supplied with blood; w hereas the light ventricle, through less acth it \ and lesser importance, begins to lag in its vascular development, a process which apparently progresses consist- cntk throughout lite. 152 THE BLOOD SUPPLY TO THE HEART As old age approaches, the individual is ushered into an era of many dangers through right-sided heart decline. Thus, the possibility from death by right-sided heart paralysis in infectious diseases increases with age, and death from pneu- monia in old age, so frequent that it is practically "physio- logical," comes perhaps somewhat nearer to our comprehension when we consider that this lagging right-sided circulation, reacting upon the right ventricle, produces a physiological right-sided decline or increasing heart failure. The lung tissue, which depends largely upon the blood from the pulmonary artery for its nutrition, receives an increasingly sluggish supply and becomes, therefore, a more and more suitable soil for a terminal infection. (Oertel states that in a long autopsy experience of almshouse cases, many of which con- cerned, of course, senile decrepits, it was not infrequent to discover unsuspected pneumonias in sudden deaths; for example, in individuals who had retired at night in apparent relative health and were found dead next morning. This has also a certain medicolegal interest.) Perhaps it is, therefore, permissible to paraphrase in this connection the old adage about a man being as old as his arteries, so as to read, "A man is as old as his Right Coronary Artery-" BIBLIOGRAPHY Abboi i, M \i in I . Monograph on congenital cardiac disease. Osier and McCrae's Modern Medicine, Philadelphia, [915, i\- \< 1.1 r, R. B. Delayed death in coronary thrombosis. •/. A. M. M. Assn., 19 19, Ixxiii. Albrecht. Der Herzmuskel und seine Bedeutung liir Plnsiologie, Pathologie und Klinik des Herzens, Berlin, 1903. \mkno.miva. Uber die Beziehungen zwischen Koronararterien und Papillarmuskeln im Herzen. Vircbow's Arch.f. path. Anal., Berl., nim, excix. Aschoff. (1) Uber den Glykogengehalt des Reizleitungssystems des Saugetierherzens. Verbandl. d. deutscb. path. Gesellsch., Berl.; Jena, 1908, xii. (2) Deutsche med. Wcbnscbr., Berl. and Leipz., 1908, No. 9. Banchi. (i) Le variazioni delle arteriae coronariae cordis et la morphologia di questi vasti. Sperimentale. Arcb. di biol. Firenze, 1903, Kii. (2) Morfblogia delle arterie coronariae cordis. Arch. ital. di anat. e di embriol., Firenze, t <><>4, iii. Bardeleben. Lehrbuch der systematischen Anatomie des Menschen, Berlin-Wien, 1906. Barker and I Iiusc .111 elder. Effects ot cutting branch of the His bundle going to left ventricle. Arcb. Int. Med., 1909, iv. Bayne-Jones. (i) Blood-vessels of the heart valves. Am. J. Anat., [917, \\i. (2) Johns Hopkins Hosp. Rep., mho, xviii. Bi \i ke, F. W. I 1 ) Die anatomischen Grunblagen der Constitutions- anomalien des Menschen, Marburg, 8, [878. (2) Oder das Volum des 1 lerzens und die Umfange der grossen Arterien des Menschen. Scbrijten der Gesellscbafl zur Beforderung der %esamten Naturwissenscbaften /.u Marburg, iSSi, xi, 4, Suppl. 2, Kassel. Bernays. Morpbol. Jabrb., Leipz., ii. Beraud. Insertions superieures du pericarde. Gaz. mid. de Par.. 1S62. Bettelheim, K. Uber die StSrungen derl terzmechaniknach Compression der Arteria coronaria sinistra des Herzens. Ztscbr. j. klin. Med., Berl, [892, sx. i53 i54 BIBLIOGRAPHY Bezold, A. von. Von den Veranderungen des Herzschlages nach Ver- schliessung der Koronararterien. Untersuchungen aus dem ]>hysiolo- giscben Laboratorium zu Wurburg, i86~, ii. Bezold, A. von and Breymann, E. Von den Veranderungen des Herz- schlages nach Verschliessung der Koronarvenen. Untersuchungen aus dem pbysiologiscben Laboratorium zu \]'urburi>, i86 - , ii. Bizot, J. Recherches sur Ie coeur et Ie systeme arteriel chez I'homme. Memoires de la Societe med. d' observation, Paris, 183-, i, 8. Bochdalek. Zur Anatomie des menschlichen Herzens. (1) Uber die sogenannte pars membranacea septi ventriculurom cordis. (2) Uber die foramina Thebesii. Arch. J. Anat. (Anat. Abt.), Leipz., 1868. Boi rceret. Les circulations locales: la main, Paris, 1885, xiii. Bral'nig, K. Ueber muskulose Verbindungen zwisclien Vorkammer und Kammer des Herzens. Berl. klin. Wcbnscbr., xli. Cadiat. Etude sur I' anatomie et la physiologie du coeur. Bull. Acad, de med., Par., iS _ q, via. Caldam, L. M. A. and Caldani, F. Icones anatomicae, etc., iii, 1810, Venetia, 1 801 -14. Chiari. (i) Uber Netzbildungen im rechten Vorhofe des Herzens. Beitr. z. path. Anat. u.z. alls. Path., Jena, 189", xxii. 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Arcb.f. d. ges. Pbysiol., Bonn, 1893. (2) Results of ligation of the coronary artery. J. Pbysiol., Lond., 1894, w . Pb mi. \m. J. I'ln siol., vol. 1. Pi rkinj] . Mikroscopische neurologische Beobachtungen. Arci&. /. Anal. u. I'ln sin!. (Muller's), Leipz., il~>4i. 162 BIBLIOGRAPHY' Putjatin. Uber die pathologischen Veranderungen der automatischen Nervenganglien bei chronischen Herzkrankeiten. Arch. J. path. Anat., u. Physiol, BerL, 18-8, Ixxiv. Recklinghausen, von and Zenker. Uber die Storungen des Myokardi- ums. Verbandl. d. 10 int. med. Kong., Berlin, 1891. Redwitz, von. Der Einfluss der Erkrankungen der Koronararterien auf die Herzmuskulatur mit besonderer Beriicksichtigung der chronischen Aortitis. Virchow's Arch., BerL, 1909, cxcvii. Reid. ( 1) On the measurements of the heart and tables on the weights of the most important organs of the body at different periods of life. Heart. Todd's Encyclopedia, London, 1843. Reitmann. 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INDEX OF PERSONAL NAMES Abbott, Maude E., -2 Amcnomiya, 23, 83, 90 Anderson, 106 Ashcroft, 39, 81, 84 Banchi, 80 Bayne-Jones, 9, 55, 56, 58 Bcncke, 109 Bi 1 mil, 79 Bettelheim, 80 von Bezold, 79 Bickell, 80, 84 Bizot, 109 Black, M., \l Bochdakk, 50, [00 Bochefontaine, 80 Boll, 105 Branch, xi Breymann, 79 liriicki , 29 Cadiat, i4 Caldani, -i>, 84 Cheney. II. II.. 8 Chiari, 84 Chirac, 78 ( !oen, 54 Cohnhcim, Ho, 82, 89 ( loplin, niii Councilman, 1 12 Cruveilhier, 30, 79, 94, 99, 1 Curran, 40 Darier, 54 Dock, 81 , 84 DngicI, 3.1 I eff, 80 Droguell, So, 82, 84 Dutto, 2 Einthoven, 1 1 2 Engel, 109 Engelhardt, 84 Fngelmann, 30 1 n, -i) I il mger, 31) ;6, 57, 67 I In', 39 Fallopius, 1, 30 Fantoni, 29 Fenoglio, 80, 82, 84 Flack, 39, 40, 41 Forstcr, 54 Frey, 54 von Frey, 80, 84 1 u, 2, 81 Fujinami, 82, 89 Galli, 81. 84, on, 138 Gaskell, 31; Gerlach, ^4 Glew, 2 Gross, \ ii Haas, Georg, 41, 42, 46, 47, 52 Holier, 1, -8, 84, 100 I [ansemann, 105 1 laucll, 3 I [enle, 54. 79, ioo Ikring, 39 Herrick, 81, 83, 84, 91 I [erxheimer, 106 I leu son, 3 I [ildebrand, 2 I [irsch, S2, 89, 90 I lis, W. Jr., 39 Howell, 75 Huber, 81,84 Huchard, 84 I [yrtl, 1, 2(j, 30, -9, mo Jamin, 2, 81, 84 Jenner, 79 Joseph, 54 Keith, 30, 40, 1 1 Kent, 39 Koch, 31), 40, 4.;, 46 Kollikcr, ,-4 Kolster, 80, 84 KSnigi Koster, 19, i j Krause, 79 165 1 66 INDEX OF PERSONAL NAMES Krehl, 81, 84 Kronecker, 80 Kiirschner, 57 Lancisius, 100 Langer, 54, 55, 57, 67, 79, 89, 100, 10 1 Lannelonguc, 101 Le Cat, 102 Lewis, 112, 113 Lexer, 2, 108 Lusclika, 54, 56, 100 Manzone, 57 Marshall, 94, 102 Matthews, 82, 84 McCordick, 10 McWilliams, 80, 84 Meigs, 19 Merkel, 2, 81, 84 Miller, 2, 82, 84 Minot, 105 Moenckeberg, 39, 41, 49, 50, 52 Morgagni, 29, 30, 78, 84 Morgan, J. D., xi, 7 Miiller, 106, 1 io, 150 Notkin, M., 71 Nussb;ium, 1, 23, 55, 3, 83, 84, 1 01 Odinzow, 55, 57, 58 Oertel, Horst, xi, 105, 106, 107, 152 Opitz, 2 Oppenheimer, 90 Osier, 75, 81, 84 Pagenstecher, 84 Panum, 79 Parry, 79 Piquard, 29, 103 Pitts, xi Porter, 80, 82, 84, 94 Pratt, 89 Purkinje, 39 von Recklinghausen, 82, 89 Reid, 94, 106 Reitmann, 106, 107 Ribbert, 19, 74 Riolanus, 1, 30 Rokitansky, 54 Rosenstein, 54 Rothschild, 90, 91 Roussy, 80 Roux, 105 Riihle, 53 Samuelson, 79, 81, 84 Sand, Rene, 107 Sappey, 54 von Schulthcss-Rechberg, A., 80 See, G., 80 Seniple, xi de Senac, 78, 84, 100 Siding, 102 Skinner, 2 Smith, 3, 83, 84, 90 Spalteholz, 4, 41, 81, 82, 84, 90 Stegmann, 3 Sternberg, 33 Tandler, 29, 30, 40, 37, 94, 101, 102, 104 Tawara, 39, 41, 81, 84 Thebesius, 78, 83, 84, 100, 10 1 Theile, 100 Theilhaber, 106 Thorel, 39, 84 Tigerstedt, 80, 84 Valentin, 109 de Vecchi, 74 Vesalius, 1 Verheyen, 100 Vieussens, 100 Virchou , S4 Waugh, \, in- Webster, H. E., xi Weed, 107 West, 84 Winslow, 94, 100 Zimmerl, 80 Zinn, IOO Zuckerkandl, 99, 100 SUBJECT INDEX Acute endocarditis and congenital cardiac defects, 72, 73 Age period changes in blood supply, 105 152 anastomoses, Functional value in age, 150 anemia, right-sided, relative, 151 average heart of first decade, 113 - second decade, 1 14 - third decade, 1 14 - fourth decade, 1 14 fifth decade, 137 sivtll decade, I 3- — seventh decade, 1 37 - eighth decade, 1 3- — bone-marrow, conclusions of Waugh, 107 — compensating anastomoses, 138 — contrast cj| heart a1 birth and seventh decade, 1 3S < loplin finds instabilit \ oi thymus, 106 degeneration, senescence and new grow tli. i"i ductless glands unstable, m<> emlji yo development, tog fat-vessels increase proportional to age, 151 heart hypertrophy in age, 1 12 hyaline glomeruli in kidneys ol children, 1 of > injected specimen oi heart at birth, 1 13 mass of right and kit ventricles, table of, I I I MUller's studies and conclusions, 1 10 Muller's weight ind measure- ments of the heart, [on Oertel's si ml\ 1 1! pancreas, 107 pia arachnoid, structural modi- fications in, 10- postnatal evolution of the spleen, 1 \ oiutions, sinus, 10S ( lertel's ci m< lu 167 Age period changes, postnatal, heart de- velopment, 1 1 3 — rami telae adiposae part ol nutritional reserve structure, I -;o — Reid's measurements ol the heart, 106 Reitmann s studs ol the pancreas, 106 right-sided heart decline in age, 1,-2 seventh decade, rami telae adi- posae, increase in calibei in, 140 -vascular architecture in, ■49 spleen, [07 subpci icaulial and subeni tne ous fat, [10 — Theilhaber finds instability in the endometrium, 106 tortuosity ol vessels accounted for, 151 turning point in heart growth, 110 Anastomoses between the coronary ait cries, 77-92 anesthetics, correct choice ol in experi- ments, S2 — arteriae telae adiposis cordis, 85 -auricular and ventricular walls seat ol e\tensi\ e, 85 branches ol each arterj anastomosed, 89 ( aids in'- dissect ioiis, -i) — capillar) anastomosis numerous, 85 — chrome-yellow injections, si -clamping experiments of Cohnheim and von Schulthess-Rechberg, Mo - conclusions as to existence of, 89 COronarj arteries and adjacent vessels anastomosed. So earliest historical experiment . 78 I 1 a risen' experimental ligatures ol coronaries, 79 I act 01s , mployed In various investiga- tors, 77 functional end-arteries, 89 1 68 SUBJECT INDEX Anastomoses, Haller's conclusions based on dissection, 78 — heart the richest organ in, 84 — Herrick's clinical classification of angina pectoris, 83 — Hirsch's tying-off experiments, 82 — HyrtI denies existence of, 79 — in heart universal, 89 — infarcts, Amenomiya's conclusions, 90 — and compensation, 91 — formation of, 1S9 — Hirsch's conclusions, 90 — interventricular septum seat of exten- sive, 85 — investigations of Thebesius, 78 — Langer's comprehensive findings, 79 — ligation experiments in dogs, 80 — Nussbaum finds connection between arteries and veins, 83 obliteration ol coronary branches, results of, Si — Parry and Jenner's findings, 79 — radiographing red lead injected arteries, 81 ■ — right and left arteries anastomosed, 89 — small vessels, complete, 85 — Smith's conclusions from experiments on dogs, 83 — Spalteholz's conclusions, 82 — vessels in the parietal pericardium, 89 Aortic valve, vasculature in, 68 Arteria circumflexa dextra, 12 Arteriae telae adiposae cordis, 22 Auricular branches of coronary arteries, 20 Barium sulphate gelatine, 8 injections, 4 Bayne-Jones' method with gelatine, 9 Bibliography, 1 -53-164 Blood supply to heart as a whole, 23-25 — to ventricles and auricles, 11-25 Blood-vessels in valves, 53 Bone-marrow, changes in, 101 Carmine gelatine, 9 Chrome-yellow injections of coronary arteries, 81 Clamping corona r\ arteries of dogs, 80 < Oronarj arteries, anastomoses between, — 92 Coronarv arteries, arteria coronaria dex- tra, auricular supply, 33 ventricular supply, 31 arteria coronaria sinistra, auricular supply, 36 — ventricular supply, 34 — auricular branch, first, 20 second anterior, 2 1 branches, course of, 20 — blood supply from single, 30 branching variations and functional differences, 37 — demarcation between supply of right and left, 23 Haller's account of, 1 — Hyrtl's method of injecting, 1 lateral branch, 22 — left, anatomy of, 15 beginning of, 1 5 percentage of circulation from, 3-r rami marginales, 1 5 ramus circumflexus sinister, 16 ramus deseendens anterior sinis- ter, 15 — second main division, 15 — multiple origin of, 30 — rami descendentes, 19 rami scpti fibrosa, course of, 20 ramus ostii cavae superioris, role of, 37 — ramus circumflexus dexter, termina- tion ot, 31 — sinister termination ol, 34 ramus deseendens anterior, termina- tion of, 34 right, anatomy of, 12 — first ventricular branch, 12 percentage of circulation from, 36 ramus deseendens posterior, 1 5 terminal portion, 15 — site of origin, 29 — statistical analysis of variations in distribution, 29 — typical variation in distribution of, 26 variation, first characteristic, 35 in distribution of, 26- 38 in main branches, 31-38 most frequent seat ol, 37 Darier, conclusions of as to vessels in valves, 5 t, 55 SUBJECT INDEX 16 9 Dilatation through use of potassium sulphocyanide, io Distribution of coronary arteries, typical lions in, 26 Ductless glands, instability of, to6 ! 11I. 1 1 ob ervations on blood supply, 1 I mbryo, ventricles in the, 109 Embryogenesis of heart veins, 93 I rditis, Abbott's studj on incidence ute, 72 — of bacteria, -4 relation to musculature and blood- vessels in valves, 58, 67 — typical injection in, 67 — valvular blood-vessels as cause of, 75 Endometrium, instability of, [06 Experimental ligatures of coronaries in animals, 79 I it as nutritional reserve, ijo — brandies, 22 — proportion between subpericardial and subcutaneous, 110 Fat-vessels and functional need, 151 I ital results in animals from selecting wrong anesthetic, 82 Functional end-arteries, Pratt's definition, Gelatine, barium sulphate, 8 — carmini , 9 — pigmented, injections of, ; - — Prussian-film , 9 \periments and conclusions, 42 anastomoses as protection at t li decade, 140, 1 JO led, 1 •; 1 lv< rage, in Brs1 decade, 1 1 3 in second decade, 1 14 — in third decade, 1 14 — in fourth decade, 1 14 — in fifth decade, [ 5- in sixtll decade, I 5 - in seventh decadi . 1 | in eighth decade, 1 i~ 1S1 in i in illation of, at birth and seventh decide, 1 j8 — embryonic right-sided development, 15 1 li it-sided development, 151 Heart, postnatal evolution and effects on function, 138 — right-sided decline in age, 152 — tortuosity of vessels, increasing, 151 — valves, frequency and duration of compression of, 75 influence of age on inatomii J changes, 75 1 111 rick's clinical classification oi pei toris, 83 I li-. bundle, histology, 40 II, ilmc glomeruli in kidneys ol children, [06 Infucts, age of individual as affecting formation of, 90 — Amcnomiva's conclusions, 90 — factors in determining, 92 — Hirsch's conclusions, 90 — situation of, 90 — variability of occurrence, 90 Kfister's theory of embolic endoc S3 Left coronarj artery, anatomy of, li — limb ol neuromuscular structure source of nourishment, 4.7 Ligation experiments on dogs, 80 Measurements of the heart, 106 Metal injections in coronarj artery, 1. 2 Multiple origin of corollaries, 50 Neuromuscular tissue, blood supply to, 39"5 2 auriculoventricular node, po itiori of, [9 auriculoventricular node, special blood supplj , 41 author's findings differ from Koch's, 45 bundle, fat and pigment in, \'i ■ specificity of blood supply to, 50, Haas' experiments and conclu 42 His bundle, histology of, 40 left limb ol neuromuscular structure, 4" ramus lerioris, 45 ramus septi fibrosi, origin and course of, 46, 48 170 SUBJECT INDEX Neuromuscular tissue, right limb of neuro- muscular bundle, course of, 47 — scarring of bundle, 50, 51 — sino-auricular node, position of, 39 vascular system, 40 — structure, description of, 39 — vascular variations alter blood supply, 48 Normal valves, conflicting opinions as to vessels in, 53 Obliteration of coronary artery, age of individual as affecting, 90 compensation in, 91 effects of, 5 1 — varying results of, 81 — coronary branches, results of, 81 Pancreas an unstable organ, 106, 107 Papillary distributions, 19 — muscles, 19 Parietal pericardium, connections between vessels of and coronary arteries, 89 Pars membranacea septi, 20 Pathological lesions due to interrupted blood supply, 49 Pericardium, anastomoses between coro- nary arteries and those of, 80 Pia arachnoid, structural modifications in, 107 Postnatal evolution, Oertel's conclusions, 108 Potassium sulphocyanide for dilatation, 10 Prussian-blue gelatine, 9 Purkinje fibers, distribution of, 49 Radiography in study of vascular struc- ture, 2, 4 Rami anteriores, 20 — interventriculares, 19 — marginales, 15 — ventriculares sinistri, 15 Ramus circumflexus sinister, 16 — descendens anterior sinister, 15 — posterior, 15 — lateralis, 12 — ostii cavae superioris, 21, 33 — septi fibrosa, 20, 48 Red lead injections of coronary arteries, 81 Right and left ventricles, comparison of mass ol, 1 1 1 — coronary artery, anatomy of, 12 Right limb of neuromuscular bundle, course of, 47 — ventricle veins draining anterior surface of, 98 Ruble's theory of endocarditis, 53 Serial sections, unreliability ol, 42 Site of origin of coronary arteries, 29 Smith's studies ol anastomoses in dogs, 83 Spleen, changes in, 107 Statistical analysis of variations in distri- bution of coronary arteries, 29 Sulcus terminalis, 21 Technique employed in these studies, 1-10 Theoretical heart capillary distributions, 19 deeper divisions, 16-22 papillary muscles, 19 representing average specimen, 1 1 — superficial divisions, 11-16 Thymus, instability of, 106 Tying-off experiments on dogs, 82 Valve musculature decreases with age, 57 Valves, blood supply to, 53-76 — aortic valve, vasculature in, 68 — bacteria as factors in endo- carditis, 76 — Bayne-Jones' findings, 55, 56 — blood-vessels and musculature, 57 — conflicting opinions as to blood- vessels, 53 — coordination of conflicting views, 57 — Darier's conclusions as to vessels in valves, 54, 55 — duration of valve compression, 75 — endocarditis, author's findings in, 67 — endocarditis, relation to blood vessels and musculature, -;S, 6" — endocarditis, typical injections in, 67 — essential to theory of embolic endocarditis, 56 fetal valves, musculature, 71 fetal valvular endocarditis, - i — infantile valvular endocardit i--. 7 1 — Luschka on vascularization, 54 mitral valve, aortic cusp, 71 — musculature decreases with age, 57 SUBJECT INDEX 171 Valves, blood supply t<>, normal heart rarely shows vasculature, 72 ■ — parallelism of congenital anoma- lies and endocarditis, 72, 73 — regression of blood-vessels and musculature, 58 — of musculature, 71 Riihle's theory of endocarditis, 53 valvular endocarditis in adults, 71 — endocarditis, relation of blood vessels to, 74 — vasculature in valvular endocar- ditis, 72 Variation in main branches of coronary arteries, 31 -38 — veins of the heart, 102 Vascular variations alter blood supply, 48 Veins of the heart, 03-104 foramina Thebesii, 100 divisions of, 101 — in embryonic life, 102 Veins, of tin heart, methods of injecting, to sinus coronarius, 93 truncus communis, 103 ■ variations in, 102 vena coronaria cordis sinistra, 04 dextra, 97 sinistra, 93 vena Galeni, 103 vena mterventricularis anterior, 94 vena interventricularis poste- rior, 97 vena marginis acuti, 97 vena obliqua atrii sinistri (\Iar- shalli), 97 — venae magnae cordis, 93 venae mintmae Thebesii, 100 venae parvae cordis, 99 venae ventriculi dextri, 98 — sinistri, 97 Venae Thebesii, too Wax medium of Lexer and Hildebrand, 2 Paul B. 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