Paper - Variations and anomalies of the venous valves of the right atrium of the human heart (1929)

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Yater WM. Variations and anomalies of the venous valves of the right atrium of the human heart. (1929) Arch. Path. 7: 418-441.

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Thebesian valve - (valve of the coronary sinus) is a semicircular fold of the lining membrane of the right atrium at the orifice of the coronary sinus.

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Variations and Anomalies of the Venous Valves of the Right Atrium of the Human Heart

Wallace M Yater, V D Fellow in Medicine, The Mayo Foundation

Rochester Minn

Submitted for publication, Oct 8, 1928

The eustachian valve or valve of the inferior vena cava and the thebesian valve or valve of the coronary sinus are normally both remnants of the right valve of the sinus venosus.


In the embronic development of the heart, accoiding to the woihs of His/ Boin “ and Rose,^ the single atrial cavity is divided into its two definitive chambers in the following mannei The septum piimum arises fioni the mid-dorsal wall of the atrium and eventually fuses with the endocardial cushions at the juncture of the atiial and ventricular cavities A perforation of the septum primum occurs to form the foramen ovale. This is subsequently closed by the fusion of the left valve of the sinus venosus and the septum secundum, which appeals in close proximity to the septum piimum as an outgrowth firom the ventral and the caudal wall of the right atiium (fig 1)

The right horn of the sinus venosus lags somewhat in its evolution and is taken up in the wall of the right atrium, which causes the opening into the right atrium of the superior and the inferior venae cavae The right valve of the sinus venosus at one time nearly divides the right atrium into two chambers, but later it becomes progiessively lowei, its cephalic poition remainmg as the ciista terminals, its caudal portion being divided to foim the valve of the inferior lena cava (eustachian valve) and the valve of the coionaij sinus (thebesian ^alve) As the left horn of the sinus venosus is migiating across the posterior wall of the atrium during the stage of absorption of the remainder of the sinus, it projects into the lumen of the atrium as the infeiioi sinus septum and divides the caudal position of the light sinus valve into these two definitive valves The opening of the left hoin of the sinus venosus is the left duct of Cuviei, which is thus pulled over to a place beneath the orifice of the inferior vena cava and persists in part as the coronary sinus The septum spurium is a veitical ridge foimed by fusion of the light and the left valves of the sinus venosus on the dorsal and the cephalic walls of the right atrium, and this is also taken up into the wall of the atrium as it expands It paitly remains, however, to form the uppei- most portion of the ciista termmalis, where it sepaiates sharply the orifice of the supenoi vena cava fiom the atrial appendage

1 His, W Anatomic menschlicher Embrjoncn, Leipzig, F C W Vogel, 1885

2 Born, G Ueber der Bildung der Klappen, Ostien und Schweideu ande im Saugetierherzen, Anat Anz 3 606, 1888, Beitrage zur Entwicklungsgeschichte des Saugethierherzens, Arch f mikr Anat 33 284, 1889

3 Rose, C Beitrage zur vergleichenden A.natomie des Herzens der AVirbel- thiere, Morphol Jahrb 16 27, 1890

The eustachian valve selves to direct the blood in embryonic life from the inferior vena caAa into the left atrium through the foramen ovale The thebesian valve possibly serves to prevent reguigitation of the blood into the coionaiy sinus duiing aunculai systole This sup- position, however, seems unlikely since the thebesian valve is usualh incompetent, that is, it is not sufficiently extensive to close the oiifice of the coronary sinus, or, if so, is usually fenestrated

Fig 1 — Inner view of the dorsal wall of the heart of a 10 mm human embryo Drawn from a Ziegler model of one of His’ embryos (after Jordan, H E, and Kindred, J E Textbook of Embryology, New York, D Appleton & Company,

Description of the Adult Valves

The eustachian valve is usually a muscular and membianous fold m the light atrium extending posteiioiily from below the fossa ovalis and then upward just anteiior to the oiifice of the infeiioi vena cava, in the uppei poition of which it is lost Its free margin is concave and directed upward and forwaid, its adheient bolder is convex and directed down- ward and backward One of its sui faces is turned laterally towaid the atiium, the other medially toward the \essel The lowei portion is a tiansverse musculai iidge (the sinus septum) continuous with the limbus fossae o\ahs, the upper portion is usuall} membranous Often the membianous pait of the ^al^e contains thin strands of ordinary cardiac muscle, especially m its attached portion Often, also, it has fenestrae, and sometimes has thin stiands of endocardium attached at two points along its edge oi foiming a little netwoik theie The valve is usually not 11101 e than 1 cm wide in the adult In some cases, the eustachian Aalve IS inconspicuous oi entiiel}' lacking In otheis, it is bioad, project- ing far into the right atiiuni Sometimes it is thin and flabby, some- times fibrous and taut

The thebesian Aalve is diiectly below the lowei ixntion of the eustachian A'^alve in the space betAA'^een this and the edge of the atnoA’^en- tncular foianien at the junctuie of the loAvei poition of the interatrial septum and the posteiioi Avail of the atiium m close association Avith the mouth of the coronary sinus, to Avhich it is usually placed lateially It is fiequently semilunai oi ciescentic AAuth its anteiioi fiee edge concave, and its posteiioi attached edge coiiAex It is often fenestiated oi made up of a netAA'^oik of thieads In fact, its size and foim aie extiemeh Aaiiable It may be absent, lepiesented meiely b} a thin, narrow ridge

Fig 2 — Right atrium \\itli the lateral wall removed to show the relationship of the orifices of the atrium and the usual forms of the eustachian and the thebesian vahes, VE, eustachian vahe, V Th , thebesian ^alve, Ap, auricula posterior, Vc'i, inferior vena cava, Ct, crista terminahs, TL, tuberculum loweri, V cs, superior vena cava, LV , limbus vieusscnii, EL, Foramin Lanne- longeus (after Tandler, Julius, m Bardcleben Handbuch der Anatomic des Herzens, Jena, Gustav Fischer, 1913)

on the posteiioi edge of the mouth of the coionaiy sinus, oi piesent as a large membrane completely coA'^eiing the sinus orifice It may even be anterior to the oiifice, placed obliquely, transveisely oi vertically acioss it Usually, it IS thin and tianslucent Sometimes theie is a definite connection betAveen it and the eustachian vaUe The oiifice of the coronal y sinus with its A^alve often lies m a sacculai depiession between the loAver portion of the eustachian A^ah^e and the atiiOA^entricular rim, this IS the appendix auncularis posterioi of His oi the subeustachian sinus of Keith Figuie 2 sIioavs the most common form of the A'ah'^es and their relationships in the atrial caAut)'^


Anomalies of these valves are dependent on the degree of the regression of the right and the left valves of the sinus venosus, the septum spurium and the sinus septum Heaits with defective development of the mteratiial septum may contain all giades of peisistence of these foui structures, but the completely developed heait presents lelatively few types of anomalies of the valves In the adult heait, rudiments of the light venous valve are found at the shaip anterior rim of the oiifice of the inferior vena cava, extending upwaid to the uppei poition of the crista teiminalis and downward acioss the orifice of the coionaiy sinus towaid the tricuspid orifice Remnants of the left venous ^alve aie situated on the interatrial septum in the posteiioi legion of the annulus fossae ovalis and the iiitei venous tubeicle (tubeiculum loweii), which is merely an eminence superioi to the fossa ovahs between the oiifices of the venae cavae Residual stiuctuies of the septum spuiium aie found anteiioi to the mouth of the supeiioi vena cava neai the inteiatiial septum Remnants of the sinus septum aie seen noimally in the mus- cular iidge that extends fiom the lowei end of the limbus fossae ovahs to the inferior pait of the iim of the oiifice of the infeiioi vena ca^a and becomes a pait of the noimal eustachian valve If the infeiioi sinus septum has merely fused with the right venous valve and has not divided it, the eustachian and the thebesian valves aie foimed as a con- tinuous fold with an attachment to the wall of the atiium in the legion of the infenoi sinus septum If the infeiioi sinus septum has failed entirely, the two valves aie seen as a simple membiane or leticulum unattached except peihaps posteiioily to the wall of the atrium

Review of the Literature

So far as I know, a leiiew of the literatuie legaiding these anomalies has nevei been made

Lindes ^ described the heart of an infant, in which theie was a single atiial cavity and othei congenital anomalies The stiuctuies piesent weie similai to those that Ruge,"* in case 2, inteipieted as peisistent light and left venous valves

Maiei ° lepoited an adult heait in wdiich theie w^eie tw'^o folds in the light atiium, mteipieted b} Ruge, in case 13, as a peisistent light Aenous vahe and a lemnant of the septum piimum

4 Lmclcs, G Em Beitrag zur Entw ickelungsgeschichte des Herzens Tnaiig Dis , Dorpat, 1865

5 Ruge, Hans Ueber Defecte des Vorhofsscheidewand des Herzens, Virchows Arch f path Anat 126 323 1891

6 klaier, R Zur Casiustik der Herzfehler, Ber u d icrliandl d nat Gesellsch 4 478, 1867

Schmidt stated that in adults now and then the eustachian valve is lengthened upwaid to the anteiioi edge of the stipeiioi vena cava, and that sometimes a broad communication exists between the eustachian and the thebesian vahes These foims lepiesent a slight incompleteness of 1 egression of the light venous A'alve to its final adult vestige as the eustachian and the thebesian valves These foims aie, indeed, not uncommon

Rokitansky® piesented two cases of anomalous membianes m the light atiium that Chian '•* latei concluded lepiesenled the light venous valve (Rokitansky’s case 16) and the left ^enous valve (Rokitansky’s case 17)

Lauenstem desciibed a ^allatlon of the valves that he had obseived fi^e times in 100 necropsies In these heaits, the two valves, eustachian and thebesian, which are oidinarily sepaiate, w'eie formed by one exten- sive membiane This common valve was a simple membiane in one case, a fenestrated membi ane in tin ee cases and a network of exceedingly fine fibers in anothei case In one case, it \vas so large that it divided the atnum into an anterior and a posteiioi chambei

Mooie’^’- lepoited a case in rvhich there ivas a large muscular fold beginning just below the fossa ovalis and sti etching from the interatrial septum near the oiifice of the infenoi vena cava to the posteiior w^all of the right atiium He desciibed a similar case in another report and stated that he had met wath one other example These w^eie probably much exaggeiated eustachian \ahes wnth an excessive development of the mfeiioi sinus septum

Leo desciibed the heait of an infant, in wdiich there were multiple anomalies and an abnormal membrane in the right atrium bounding the orifice of the supeiior vena cava and a common eustachian and thebesian valve The intei pretation in this case could not be established

Pieisz leported a case (case 5) of multiple anomalies, among which was a gieat sievelike flap at the light boidei of the infeiior vena cava and the coronary sinus, which, accoidmg to Ruge, in case 17, corresponded to the right venous valve

7 Schmidt Bidrag til kundsKaben om Iniertcts udvikhngshistories, Nord med Ark 2 1, 1870

8 Von Rokitansky Die Defecte dcr Scheidewande des Herzens, Vienna, 1875

9 Chian, H Ueber Netzbildungcn im rechten Vorhofe des Herzens, Beitr z path Anat u z allg Path 22 1, 1897

10 Lauenstem, Carl Vanetat der Klappen des rechten Atnum, Virchmvs Arch f path Anat 68 632, 1876

11 IMoore, Norman Variety in the Structure of the Heart, Tr Path Soc , London 34 31, 1883

12 Leo Hans Ueber einen Fall von Entwickelungshemmung des Herzens, Virchovs Arch f path Anat 103 503, 1886

13 Preisz, Hugo Beitrage zur Lehre von den angebornen Herzanomahen, Beitr z path Anat u z allg Path 7 245, 1890

Stadlei lepoited a case of multiple anomalies of the heait in which there was a fold arising fiom the inferior vena cava and another passing from the infeiior vena cava on the right to the inferior and posterioi end of the incompletely developed interatrial septum Ruge, in case 9, and Chian both interpieted the fiist fold as a remnant of the right venous valve and the second as the persistent horizontal ridge developing in embryonic life between the inferior vena cava and the coronary sinus (sinus septum)

Przewoski wrote conceining anomalous chordae tendureae nr the heart of man and described networks of fibers near the mouths of the great -veins in the right atiiuni and along the limbus fossae ovahs He believed these to be remnants of the venous valves of the embryo Hrs interpretation antedated Chian's moie detailed and precise description and explanations

The most interesting anomaly of the eustachian valve is that described by Chian® and known since as ‘'Chian’s network” This consists of a network of fine or coarse fibeis in the right atrium, its attachments extending from the interatrial septum or the upper portion of the crista termmalis to the thebesian and the eustachian vahes or to the region of the orifices of the coronary sinus and the inferior vena cava Chian reported eleven cases, in one of which the network was responsible foi the death of the patient, a young man aged 24 In this case, there was extensive pulmonary embolism, the source of which was apparently a small thrombus lodged in the confluence of the fibers of the network Chian concluded that the malformation repiesented the remains of the septum spurium and the right venous valve None of Chian’s cases showed any other relevant congenital anomalies except an additional case of a related anomaly The heart in this case retained large remnants of both the right and the left venous valves Chian called attention to the fact (as shown by Born in mammals and by Rose in monoti ernes and marsupials) that in these animals the venous valves persist paitly or entirely He stated that Born had also noted that in new-born human beings a semilunar ridge is often to be found under the anterior nm of the opening of the superior vena cava at the juncture of the anterior and the medial walls of the right atrium, which according to its position and direction is considered a lemnant of the free edge of the septum spunum, a trace of uhich is sometimes recognized even in adults

14 Stadler, O Ueber eine seltene Missbildung des Herrens, Verhandl d phys - med Gesellsch 24 61, 1890-1891

15 Prze^\oskl, E Anomalae chordae cordis humani, valvule -venae cavae supenons, Pam Towarz Lek Warszaw 92 400, 1896, Cystenformige Veran- derung der Semilunarklappe dcr Aorta Phlebolith des rechten Vorhofes, Sinus venosus fossae ovahs (abstr), Centralbl f allg Path u path Anat 8 152, 1897

A Weber described a remarkable example of Chian’s network Besides the mam netwoik there was a network of filaments along the posteiior edge of the membianous portion, some of the filaments hanging free and supporting a small secondary membrane Weber interpreted the mam netwoik as being derned abo\e from the light venous valve and below fiom the infeiior sinus septum, the upper poition corresponding to the eustachian valve, the lower to the thebesian He believed that in Chian’s cases, also, the lowei attachments of the network weie remains of the inferioi sinus septum and not displacements of the right venous \ahe He lefened to the woik of Milne-Edwaids, which showed that, in ceitain adult buds, the sinus poition of the right atrium is separated by fleshy strands fiom the atrial portion propei The smallei network, he believed, lepresented lemains of the left venous \ahe

Swan leported, as an example of Chian’s netwoik, a \alvehke flap of endocaidium lying against the fossa oialis on the nght side and attached to the annulus fossae oialis b}*^ anastomosing bands closel} lesembling choidae tendineae This is certainly not Chian’s network but probably a lemnant of the left venous \alve which did not completely fuse wnth the septum secundum Minor degiees of this anomaly are nof infiequent, as noted b}’' Lowet, A Webei, Oppenheimei, Mollendorf and othei s

Le Count’® lecoided an instance of Chian’s anomalj, in which the netwoik was entueh below^ the orifice of the inferioi vena cava

Loosei piesented an example of Chian’s netw^ork, in wdiich there was a thrombus about 2 cm in diametei attached to a few fibeis of the net A hemorrhagic embolic infaict was piesent in the left lung, and also thrombi in both femoial ^e]ns, so that it was impossible to deteimine whethei the thiombus on the netwoik der eloped pnmanly at that site or had been earned theie fiom the venous thiombi and had giown to its final size Looser consideied that these networks may be remnants of the 1 ight A enous ^ ah e, the left ^ enous ^ ah e the septum spunum or the sinus septum He stated that i udiments of the i ight ^ enous valve should be looked foi at the thebesian A'alve, the upper pait of the eustachian ^alve and the ensta tenninalis, lemnants of the left venous \alve should

16 Weber, A Formation reticulee de Toreillette droite et fosse ovale anor- male d’un coeur bumain adulte, Bibhog anat 6 17, 1898

17 Swan, J M Fenestration of the Right Auricle, Proc Path Soc 2 71, 1898-1899

18 Le Count E R Network Formations m the Right '\uricle, wnth Demon- stration of a Specimen, Tr Chicago Path Soc 5 309, 1901-1903

19 Looser Ueher die Netrbildungen im rechten Vorhofe des Herzens, Inaug Dis , Zunck, 1902

be looked foi at the inteiatiial septum in the aiched line which connects the left boideis of the two venae cavae, and vestiges of the septum spuiium anteiioi and medial to the mouth of the supeiior vena cava near the inteiatnal septum Faiily laige lemnants of the light venous valve aie by fai the most common, those of the left venous valve are moie laie, and any notable lemnant of the sinus septum is unusual Looser disagreed with Chian, maintaining that the lattei’s eleven networks were all remnants of the light lenous valve without any involvement of the septum spin Him He lecognized the anomaly in which the eustachian and the thebesian valves aie leplaced by a common reticulum owing to a lack of fusion of the light venous valve with the sinus septum which normally becomes the lowei part of the eustachian valve and separates this flora the thebesian vah'e Remnants of the right venous valve are sometimes found at a gieatei or less distance from then normal site, probablj'- because of ii regulai ities in the giowth of the endocardium A lelativel}'’ common displacement is that of the threads from the crista teiminahs toward Lowei ’s tubercle The cause of this displacement is piobably the pioximity of the mouths of the laige veins and a distoi- tion of the endothelium dining the lapid giowth of the heait Theie are many transitions from the noimal condition of the eustachian valve and the thebesian valve to these reticulate stiuctuies

Ebbinghaus lepoited a case of Chian’s netwoik and accepted Chian’s explanation

A Weber discussed the question of lemnants of the left venous valve as commonly seen At the posteio-infeiioi pait of the fossa ovalis aie frequently found punched-out areas beneath which a little probe can be moved a variable distance ovei the subjacent endocardial suiface This space passes anteriorly into the fossa ovalis and posteiioily towaid the inferioi vena cava It is the pait of the fossa ovahs that lacks the pi ejecting limbus Webei inteipieted this peiforated poition as a rem- nant of the left venous valve, the space beneath lepiesenting the intei- septovalvulai space of Rose The left venous valve fuses not only with the septum secundum to foim the limbus of the ostium secundum but also diiectly with the septum pnmum anteiioi to the posteiior iim of the septum secundum Webei quoted Giossei as having found a pei- sistence of the left venous valve in a ceitain number of Cheiropteia, and Devez in the American Dtdelphys The echidna (monotieme) has a valve foi each vena cava and a valve common to both The oinithoiynchus has a common internal valve lepresented by a simple musculomembianous ridge Other animals having an internal valve in the mfeiior vena cava are Myimecopha tctiadactyla, the jaguar and the cabai

20 Ebbmghaus, H Zur Kasuistik der kongenitalen Herzfehler und deren moglichen Folgen, Munchen med Wchnschr 51 797, 1904

21 Weber, A Restes de la valvule ^eIneuse gauche dans le coeur humam adulte, Bibliog anat 13 11, 1904

Woitmann^^ desciibed an infant’s heart piesenting many unusual anomalies In place of the eustachian valve, theie was a bulging, sac- like membrane, at one edge of which was attached a spheiical, blackish thiombus, “the size of a small pea ” Theie was also an independent net- woik along the left edge of the orifice of the mfeiior vena cava Avith thieads attached to Lower’s tubercle The sachke membiane was a lesiduum of the light venous vahe, the network a lemnant of the left venous valve

In Thilo's Inauguial Disseitation,-" m 1909, were desciiptions of five cases of reticula in the right atiium, two of which weie similar to Chian’s fiist foui cases In one of these, a giayish-red, “pea-sized,” spheiical thiombus was attached to the netwoik There was an embolic infarct of the lung, and also a thiombus m the common iliac vein, so that the source of the pulmonary thrombus may ha\e been fiom this and not from the thrombus of the reticulum

Lesieui, Froment and Ciemieu-^ lepoited an instance of an “anoma- lous thebesian valve associated with a laige patent foramen ovale” They believed the flap to be a lemnant of the left venous valve which had failed to fuse with the septum secundum to close the foramen ovale

Mollendorf,-^ described a heait containing lemnants of both the light and the left venous valves The sinus septum had not divided the light venous valve into its two definitive valves

Haas reported an unusual case Theie weie thiee gioups of threads forming a network and leplacing the eustachian and the thebesian valves The uppermost gioup was attached to the legion of the crista terminahs beside the light edge of the supeiioi lena cava On the net hung an embolus 6 cm long and sunounded twice in its middle by a thiead This embolus had undoubtedly come fiom a thrombus in the left femoial vein and had become ensnaied in the netwoik, thus prevent- ing fatal pulmonaiy embolism

22 Wortmann, W Ueber eine seltene Herzmissbildung Zugleich ein Beitrag zur Frage der Netzbddungen im rechten Vorhofe, Inaug Dis , Wurzburg, 1909

23 Thilo, L Zur Kenntnis der Missbildungen des Herzens, Inaug Dis , Leipzig, 1909

24 Lesieur, C , Froment, J , and Cremieu, R Coexistence d’une communica- tion interaunculaire et d’une anomalie de la valvule de thebesius, Lyon med 116 1045, 1911

25 Von Mollendorff, Wilhelm Ueber abnorme Erhaltung der Sinusklappen im rechten Vorhof ernes menschhchen Herzens, Anat Anz 40 406, 1912

26 Haas, W Ueber einen weiteren Fall von Netzbddungen im rechten Vorhof mit einem in denselben verfangenen Embolus, Inaug Dis , Karlsruhe, 1916

F P Webei ledescribed Ebbmghaus’ case, m which he had seen the heait, and lepoited two of his own He consideied these to be examples of Chian’s netwoik, but they were piobably merely exagger- ated “openwork” eustachian valves

Joi dan’s two cases"® weie good examples of Chian’s network He mentioned a third case seen two years before Joi dan’s conclusion was “As these bands arise fiom the inteiatiial septum in the legion developed from the left valve of the sinus venosus and also from the crista termi- nalis which is the lemains of the cephalic poition of the right valve of that sinus and as they insert in close pioximity to and directly on the thebesian and eustachian valves it seems that Chian’s explanation is proper Howe\er, the left valve of the sinus venosus is also involved ” Joi dan noted that both the patients had auiicular fibi illation at the time of death, and he speculated as to the lole the network might play m pro- ducing this airhythmia because of a “close relationship between the network and the conducting system ”

Wuim^® lepoited a case of coirected tiansposition of the gieat ves- sels and described a network in the left side of the light atiium which he called an instance of Chian’s network This type of reticulum is not similar to Chian’s cases, however, and such thieads aie not extremely lare

Method or Opening the Heart

I have studied the eustachian and the thebesian valves in 120 hearts collected as a routine In order to preserve the eustachian valve intact it was necessary to modify the technic of opening the heart

In a heart opened in the usual routine manner, the eustachian valve is cut almost directly through its middle by the scissors, as they pass between the orifices of the two venae cavae If the valve is flimsy, as it often is, its two halves collapse against the wall of the atrium and are not seen unless special notice is taken of them When it is desired to examine the valves, one may first look through the open end of the inferior vena cava into the right atrium, and, should an anomalous valve be observed, one may then open the right atrium by an incision anterior and parallel to the anterior rim of the inferior vena cava and then across to the tip of the atrial appendage from the lower end of this opening This method gives ample exposure of the interior of the right atrium and also preserves the smo- auricular node should the examiner desire to study this microscopically In removing the heart from the body, care must be taken, m cutting the inferior vena cava, not to encroach on the right atrium

27 Weber, F P Interesting Cases m Which a So-Called Chian’s Net Was Found in the Right Auricle of the Heart, with or without the Presence of any other Congenital Cardiac Abnormality, Internat Chn 3 43, 1920

28 Jordan, W R Two Cases of Chian’s Network, Arch Path 2 840 (Dec ) 1926

29 Wurm, H Angeborener Herzfehler mit “korngierter” Transposition der grossen Gefasse, Virchows Arch f path Anat 263 123, 1927


The structure of the eustachian valve vanes, but it takes lelatively few foims In the 120 heaits studied with special emphasis on these lahes, the eustachian \ahes could all be classified as of one or the other of SIX anatomic t}pes In several hundied othei heaits observed later, all of the Aahes conformed to one or the othei of these types A brief description of each type of valve with the lelative number of heaits in which it uas found, follows

1 The ^ahe absent (seienteen cases) The sinus septum and the anterior rfm of the inferioi lena ca\a weie all that denoted the previous existence of a right venous ^ahe, except foi the thebesian valve, which was piesent in sixteen cases and absent in one case

2 A simple nonfenestrated flap or membiane (sixt 3 -nine cases) The usual form was ciescentic It Aaiied fiom a narrow little fold along the antenoi edge of the oiifice of the infeiioi ^ena cava, to a broad membrane 2 3 cm wide The a al\ e, in some cases, was a thin, flabby, transparent membiane distinct fiom the iim of the \ena cava, and in some cases it was a tough, taut fold meiging with the iim of the vena ca^ a and the w^all of the ati lum It sometimes had muscle fibei s in it, especially thin, narrow' stiands near the attached edge

3 A fenestrated semilunai membiane containing fiom one to many fenestrae (tw'enty-tw'o cases) In one of the cases, it had accessor} threads on its surface In most of the cases, the valve w'as thin Some- times It was narrow' or bioad and ^ell-llke

4 A lahe formed in part or entirely of a netw'ork of thieads (seven cases) In some of the cases this looked like a cobweb

5 Both the eustachian and the thebesian ^ ah es formed of one mem- brane (tw'o cases) In one case the tiansverse sinus septum w'as lacking

6 Chian’s network (thiee cases) One othei instance of Chian’s network w'as found in a pieseived heait

Of the 120 hearts, tw'eh e had definite connecting tissue betw'een the eustachian and the thebesian lahes The aveiage w'ldth of the simpler forms W'as 0 35 cm and the aieiage length at the fiee edge 3 42 cm The minimal width w'as 0 15 cm and the maximal 2 3 cm The minimal length at the free edge w'as 1 7 cm and the maximal 7 5 cm

The thebesian ^alve varied anatomically more than the eustachian The thebesian i alves in these hearts may be classified as follow's

1 The valve absent (thirteen cases) The coionaiy sinus opened diiectly into the atrial cavity

30 All descriptions and measurements of the lahes are given as for a heart held w'lth the long axis lertical, the observer looking at the right side of the interatrial septum

2 A simple nonfenestiated fold attached to the posterioi edge of the oiifice of the coronary sinus (sixty cases) This vaned fiom a iiariow little run to a broad meinbiane extending ovei the sinus orifice The predominating shapes weie crescentic, semilunai and tiiangulai The valve was usually thin

3 A simple fenestrated membiane (seventeen cases) This type vaned fiom a thin crescentic flap to a laige fold covering the orifice

4 A lathei simple fold with one oi moie accessory threads (seven cases)

5 A simple vertical bai (two cases)

6 A valve consisting of fine thieads only (four cases) In two of the cases, the threads foimed a netwoik m the sinus orifice In one, a thiead lan obliquely acioss the oiifice

7 A U-shaped fold with the sinus oiifice between the limbs (five cases)

8 A valve lepresented by complicated membianes passing veitically across the sinus orifice (foui cases)

9 The thebesian and the eustachian vahes foimed by one fold (two cases) In one of these cases, the tiansverse sinus septum was lacking

10 Miscellaneous type (six cases) (a) an inveited U-shaped fold with the sinus orifice between the limbs , (h) a ci escentic fold with strands anterioi to the sinus oiifice, (c) a crescentic fold with a branch, (d) a netwoik over the sinus orifice, (e) a large, fenestrated veil in the sinus oiifice with anchoring strands, and (/) a tiiangular fold with one fenestra, attached to the mferioi iim of the sinus orifice

Only thiee or at most foui of these valves may be consideied at all competent, that is, sufficient to close the oiifice against a backflow The aveiage horizontal width of the simpler foims of these valves was 0 6 cm and the average vertical width 1 05 cm The minimal horizontal width was 0 05 cm and the maximal 2 2 cm The minimal vertical width was 0 6 cm and the maximal 2 cm

In another series of hearts from fifty adults, the thebesian valves weie of somewhat similar types to the postenoi iim of the oiifice, (b) a netwoik with an accessoiy thread anterioi to the sinus oiifice, (c) a laige, horizontal, fenestiated membiane in the sinus oiifice extending fai out anteiiorly, with anchoi- ing strands to the sinus infeiioily, and joining the eustachian valve at its postenoi end, and (d) a membrane stretching obliquely across the sinus orifice with a veitical bianch anteiioi to the orifice

1 The valve absent (five cases)

2 A simple nonfenestrated fold attached to the posterioi edge of the oiifice of the coronary sinus (twenty-six cases)

3 A simple fenestrated membiane (nine cases)

4 A Cl escentic fold witb accessory threads anteiioily (two cases)

5 A simple vertical bar (two cases)

6 A simple horizontal bai (two cases)

7 Miscellaneous types (four cases) (a) fenestiated veitical mem- brane anteiioi to the sinus orifice with a stiand acioss the sinus oiifice

The aveiage hoiizontal width of those lalves that could be measuied was 0 78 cm and the aveiage veitical width 103 cm The minimal horizontal width was 0 15 cm and the maximal 2 3 cm The minimal veitical width was 0 6 cm and the maximal 2 cm

The simplest foims of the eustachian valve aie usually associated with the simplest forms of the thebesian valve When one is fenestiated the other is usually fenestiated also

From this senes of heaits, with the addition of a few other specimens, one can select a numbei of cases which ilhistiate a giadual piogiession from unusually large but sti ucturally noi mal valves to those valves which show features due to some embiyologic deviation The gioup of heaits to be desciibed includes all the types of anomalies that have been descnbed in connection with the venous vahes of the right atiium in the adult structure

Report or Cases

Casp 1 — The eustachian vah e was a large, tougli, fenestrated semilunar membrane, 3 S cm long at its free edge and 1 5 cm broad at its greatest width (fig 3) Muscle strands vere not visible macroscopically Seen through the orifice of the inferior vena cava from without, the valve seemed almost to co\er the orifice of the vein The thebesian valve was similar, but much thinner, and the fenestrae were proportionately larger There was nothing especially remarkable about these valves They merely represented the more exaggerated type of the usual form

Case 2 — The eustachian valve was an openwork, fibrous, white structure (fig 4), which, in its upper and posterior portion, consisted of interlacing fibrous threads and strands The free margin of the valve was 2 S cm long and the greatest width measured 1 S cm If, instead of the fibers, this valve had con- tained more membrane, it would have closely resembled the valve in case 1 The thebesian valve was a simple semilunar fold

Case 3 — The eustachian valve was a large, flabbv, thin, white and much fenestrated veil-like membrane The free edge measured 5 cm and the greatest width 2 3 cm The thebesian valve was a large, nonfenestrated fold immediately below and almost continuous with the eustachian valve It completely covered the orifice of the coronary sinus The two valves together constituted a large remnant of the right venous vahe of the embrj^o, but conformed to the type of valves found in adults

Case 4 — A woman aged 65, died of congestive heart failure due to hyperten- sion The electrocardiogram revealed auricular flutter with an aiinculoventncular block, shifting back and forth between 2 1 and 4 1 ratios, and an incomplete right bundle branch block with a QRS interval of 0 12 second The heart weighed 684 Gm The eustachian and the thebesian valves were formed by a continuous.

large, fenestrated membrane extending from below the orifice of the coronary sinus upward in front of the inferior vena cava to a broad attachment m the roof of the right atrium about 1 2 cm posterior to the median portion of the crista terminalis This membrane was attached to the usual transverse muscular ridge that lies between the inferior vena cava and the coronary sinus (a remnant of the inferior sinus septum) and forms the lower end of the normal eustachian valve The entire membrane measured 5 cm at its free edge and 1 6 cm at its widest part It was of the type described by Lauenstem In the nonfenestrated portion of the free edge was a flat band of cardiac muscle, 0 2 cm wide, which

Fig 3 (case 1) — The right atrium is opened to show a large, fenestrated, semilunar eustachian valve and a similar thebesian valve A indicates the fossa ovalis, B the eustachian valve, C the thebesian valve and D the tricuspid valve

was continuous with the musculature of the atrium above and with that of the transverse ridge below Such a distribution of muscle raises the question whether the ring of muscle thus formed could have been the pathway of the simple circus movement of auricular flutter

Case S — A man, aged 33, had been subject to chronic mitral endocarditis and auricular fibrillation He died of congestive heart failure The weight of the heart was 707 Gm Both atria were greatly dilated, both ventricles greatly hyper- trophied and the mitral orifice thickened, rigid and stenotic The venous valves were of the type described by Lauenstein, but the inferior sinus septum had failed to unite with the right venous valve The two valves were a continuous thin membrane with a thin bridge between them (fig 5) This bridge formed an arch over the orifice of the coronary sinus, and the membrane was not attached to the wall of the atrium in the region of this arch Both the upper and the lower portions of the common valve were expanded, somewhat triangular and fenes- trated, and lay m different planes Above, the valve was attached to the wall of the atrium just anterior to the lower half of the orifice of the inferior vena cava.

Fig 4 (case 2) — The right atrium is opened to show a large, openwork eustachian valve A indicates the orifice of the inferior vena cava, B the eustachian valve, C the orifice of the coronary sinus and D the thebesian valve below, it fused with the endocardium by a wide base anterior to the orifice of the coronary sinus and a short distance above the tricuspid orifice

Case 6 — In this case, also, the two valves were united in one large membrane The transverse muscular ridge (sinus septum) was present but was connected with the common valvular fold by a little thread only There was also a network on the posterior half of the fossa ovalis attached along the posterior rim of the limbus and by short bands to the endocardium covering the fossa ovalis (fig 6)

Case 7 — A man, aged 69, died from bronchopneumonia, following colostomj^ for carcinoma of the descending colon In the left pulmonary artery was a fairly large antemortem thrombus The heart did not show anything of note except the venous valves There was a small, triangular membrane flanked by a thread on each side, which arose from the upper and anterior part of the rim of the orifice of the inferior vena cava (fig 7) The small membrane and threads

Fig 5 (case S) — The lower interior of the right atrium is exposed to show a combination of the eustachian and the thebesian valve with absence of the inferior sinus septum

quickly converged to be lost m the substance of a firm white thrombus, which was irregularly round with excrescences above and below The thrombus measured 1 3 by 0 8 by 0 8 cm From the lower end of the thrombus, some closely entwined threads emerged and passed downward and posteriorly They were attached by a triangular membranous and filamentous base to the anterior rim of the inferior vena cava, the distance between the upper end of the upper attachment and the lower end of the lower attachment on the nm of the vena ca\a being 2 7 cm From the lower part of the entnmed threads below tlie thrombus, a thread 28 cm long passed downward and vas attached to the anterior edge of an extensne fenestrated thebesian valve, measuring 1 2 bv 1 1 cm , vhich covered the orifice of the coronary sinus Another shorter thread arose from the inferior sinus septum and passing downward was attached with this longer thread to the thebesian valve

Fig 6 (case 6) — An exposure as in figure 5 The large common fold of the eustachian and the thebesian valves has been pulled to the side to show the network on the posterior half of the fossa ovalis (the network is held taut b> one cotton thread, ^)

Case 8 — The heart appeared normal The eustachian valve was a thin, trian- gular, fenestrated membrane wuth its base attached to the low^er portion of the nm of the inferior vena cava and the inferior sinus septum Its base ivas about 2 cm long, and the distance from the middle of the base to the apex, when the mem- brane was held taut, was about 2 cm From the apex, a thin thread passed obliquely across the atrium and upw'ard to be inserted on the interatrial septum just above the tuberculum lowen about 1 S cm posterior to the crista terminalis

This thread was 3 5 cm long The thebesian valve was a large thin membrane, covering the orifice of the coronary sinus and attached to its rim by threadlike processes The orifice and the valve lay in a deep recess beneath the inferior sinus septum, the subeustachian sinus of Keith

Case 9 — The heart did not play a part in the patient’s death and appeared normal There was a large, delicate, fenestrated and netlike eustachian valve attached to the rim of the inferior vena cava except in its upper portion The free edge was about 4 cm long and the greatest width was about 1 3 cm From the upper portion of the valve, two threads were given off close together and ran across the orifice of the inferior vena cava to be attached close together to the tuberculum loweri just above the limbus fossae ovahs They were about 2 cm long The thebesian valve was a large membrane similar to the eustachian valve, covering the orifice of the coronary sinus

Fig 7 (case 7) — The wall of the right atrium is removed to show an ante- mortem thrombus formed about the fibers of a reticular eustachian valve

Case 10 — The heart did not play an important part m the historj of this case A cobweb-hke network of thin, delicate fibers in front of the orifice of the inferior vena cava extended partially across the atrium A thin, narrow membrane repre- sented the usual form of eustachian \alve, and the threads of the network were largely attached along the course of this , but, for the most part, they were inserted directly into the rim of the inferior vena cava, anterior to the attachment of the valve (fig 8) In the upper part they were attached to the upper part of the rim of the inferior vena cava, independent of the eustachian valve, which ended con- siderably below this part One delicate thread, about 5 cm long, left the anterior edge of the network and ascended to the roof of the atrium, where it was attached about 1 cm posterior to the crista terminalis The whole network was flaccid The thebesian valve was a small, thin, fenestrated semilunar membrane

Case 11 — A man, aged 40, died suddenly of pulmonary embolism while under- going examination at the clinic He had been operated on elsewhere for a strangulated hernia a year before, and had suffered from weakness, abdominal pain, dyspnea and swelling of the legs at night since that time The clinical examination revealed, besides other things, an indefinite mass m the abdomen, marked edema of the left arm up to the shoulder and edema of both legs There

Fig S (case 10) — The right atrium is opened to show a cobweb-like network m connection with the eustachian valve and a long thread passing from it across the cavity to the roof A indicates the crista terminalis, B Chian’s network, C the orifice of the inferior vena cava, D the eustachian 'valve, B the thebesian ralve, and F the tricuspid valve

nas a suggestion of acromegaly in an increased prominence of the malar bones and the large square hands Necropsy revealed massive pulmonary embolism and thrombosis of the left innominate and the subclavian veins, and of the common iliac and the right iliac veins The hypophysis was enlarged to three times its normal size, and microscopically revealed carcinomatous invasion A portion of the ileum was black and edematous, with stenosis of the lumen, evidently repre- senting an old healed gangrene of the bowel from the time of the strangulation of the hernia The heart was essentially normal except for the condition in the right atrium (fig 9) Evidence of a eustachian valve or of any remnant of the inferior sinus septum was absent The orifice of the coronary sinus was 1 3 cm n ide in the collapsed state , a thebesian valve was not present Across the atrial cavity from the region of the orifices of the inferior vena cava and the coronary sinus, several delicate threads passed to an insertion into a wide, flattened and extensive crista termmahs just anterior to the orifice of the superior vena cava

Fig 9 (case 11) — The right atrium is opened to show the eustachian and the thebesian valves replaced by a Chian’s network (photograph retouched)

There were three mam threads, all more than 6 cm long, which were difficult to trace from insertion to insertion because of an entanglement in their median portions Above, these threads were attached about 1 cm apart, m a row, to the crista termmahs by little cone-shaped bits of endocardium After leaving the entanglement, which was about 1 5 cm long, they became several small threads, which were attached below to the wall of the atrium in front of and above the orifice of the coronary sinus Near the end of an unattached thread was a small discoid antemortem thrombus about 0 4 cm in diameter and 0 IS cm thick


This senes of cases pi ogi esses fiom the moie e\aggeialecl foims of the usual type of eustachiaii and thebesian vahes to those in which the valves have been leplaced by a numbei of thieadlike piocesses Cases 1, 2 and 3 aie instances of laige fenestiated foims without accessoiy threads and with the usual iidge lepiesenting the lemains of the mfeiioi sinus septum Case 4 illustiates the incomplete sepaiation of the two valves by the infeiioi sinus septum Case 5 is an example of a complete failuie of the mfeiioi sinus septum, the two valves being one membiane unmtei 1 upted by the musculai iidge In case 6, the sinus septum was piesent but failed to clea^e the light venous valve into its tw^o definitne valves The netwmik m the fossa ovahs was a lemnant of the left venous valve, which had failed to unite completely woth the septum secundum Case 7 showed a netw^oik of thieads, one of wdiich passed dowmw'ard from the eustachian netwoik to connect wnth the laige fenestrated thebesian valve In case 8, a single stiand passed fiom a much fenes- tiated anomalous eustachian valve to be attached to the intei atrial septum In case 9, two threads passed from the eustachian \alve netw^oik to the tubeiculum lo\veii A single long fibei, 5 cm long, m case 10, left the cobweb-like eustachian valve netw^oik, passed acioss the atmim and Avas inseited into the roof of the chamber Case 11 was the most abeirant form of all, both eustachian and thebesian lalves being leplaced by a number of long thieads sti etching completely acioss the atiial cavity fiom the region of the oiifices of the infenoi \ena cava and the coronal y sinus to the upper pait of the ciista teiminahs In not one of these cases was theie any other caidiac anomaly These last four cases fall readily into the class described by Chian, since they have thieadlike processes formed in association with the lenous vahes and inseited on 1 emote unnatural paits of the w'^all of the atiium

In the main, most authois have agieed on the mteipietations of these anomalies of the valves Theie aie a few’’ cases in wdiich a difteience of opinion might exist, but I feel that interpietations of caidiac anomalies aie not woith much unless the interpietei has the condition w^ell -visual- ized or has access to the heait itself

Concerning the cases designated Chian’s netw’^oik, theie aie two mam conceptions Chian concluded that the leticulum is a lemnant of the light A^enous valve and of the septum spuiium Loosei believed that it IS formed entirely by the light venous valve and a dislocation of the fibers fiom their noimal site by irregulai ities in the giow^th of the endo- cardium Jordan washed to include the left venous valve as playing a pait in the foimation of the leticulum I considei Loosei ’s explanation as the one nearer the tiuth, piefeinng to look on all folds oi netw^orks formed m association with oi leplacmg the eustacliian and the thebesian valves as lemnants of the light venous valve with or without involvement of the infeiior sinus septum Additional evidence for the theoiy that a dislocation of fibers may occur in the foimation of these reticulated stiuctuies IS the attachment, m some cases, of fibeis of the lower part of the network at points in the right atrium far below the lower limit of the right venous valve This is exemplified best, peihaps, by Chian’s case 10 Spurious thieads are seen moie raiely in the left atiium, and aie probably due to dislocations of lemnants formed usually from the septum piimum oi even the septum secundum These stiuctures weie recently leviewed by Kleine This conception limits the lemnants of the left venous valve to those thieads, netwoiks oi loose folds at the edge of the fossa ovalis and mainly in the posteiioi pait, instances of the occuiience of which, in a small way, aie fiequently seen Remnants of the septum spuiium aie then left as the raiest of all and, so far as I know, are limited to those heaits that show a definite semilunai iidge pi ejecting under the anteiior iim of the opening of the superior vena cava at the junctuie of the anteiioi and the medial walls of the light atrium Born is the only authoi who called special attention to such a ridge, which is seen most often in infants Anomalies of the sinus septum aie also lare as a distinct entity

This explanation of the oiigin of Chian’s stiuctm e confuses the ciiteiia on which to call a ceitam reticulum an instance of Chian’s network Foimations of network of the eustachian and the thebesian valves aie not uncommon, as shown by the study of the valves in moie than 120 heaits In all of Chian’s cases, however, some of the fibeis of the net had then attachment to the atrial wall near the uppei portion of the ci ista termmalis or to the interatrial septum on oi neai the tubeiciilum loweii Therefore, the term, Chian’s netwoik, should probably be applied only to leticulai foimations that possess such thieads

Clinically, these reticula aie usually not of consequence Instances are on record, however, in which thiombi were found in the reticulum Five of these have already been noted from the liter atm e, and in Chian’s case 1 such a thrombus apparently caused the death of the patient from pulmonary embolism Also, m case 11 (fig 9) of the present senes, the patient died of pulmonary embolism, but theie was extensive thiombosis of several laige veins, as well as the thrombus attached to the network In case 7 (fig 7) there was an embolus in the left pulmonaiy aiteiy, although the patient did not die of pulmonary embolism The large thiombus siiiiounding the thieads of the eustachian valve was the only source found foi the embolus In anothei case (not recoided here), the patient died of septicemia following an induced aboition She had had dyspnea foi two yeais At neciopsy, a large egg-shaped fibro- m3"xoma was found attached to the wall of the left atrium and filling it, on a thread of the eustachian valve was a laige recent thrombus In a fouith case (not lecorded here), there weie antemortem thrombi on se\eral threads of the thebesian valve These long threadlike processes hanging limp in the cavity of the right atrium and being whipped about by the blood curient must foim excellent bases for the formation of thrombi, when the late of cii dilation is depressed or the condition of the blood becomes favorable for clotting That they are whipped about iigorously is shown by cases 7 and 11, in which the threads were so entwined and entangled as to be insepaiable for some distance In Haas’ case, instead of being the souice of pulmonary embolism, however, the network prevented such a condition by catching a large embolus in its course fiom the infenoi vena cava to tlie pulmonary artery The leticulum in one of Thilo’s cases may have played a similai role, but because of the unceitainty of this I have included it as an instance of the foimation of a thrombus in situ

31 Kleine, H O Zur Morphologic der Missbildungen des Imken Vorhofs (Chorda tendinea spuria atni sinistn), Virchows A.rch f path Anat 267 281 1928

Case 4 of this series illustrates the possible mechanism by which ciicus movement ma} ensue in isolated instances The cardiac muscle bands in the large valvular fold joined with the muscle of the atrium at each end of the fold and thus formed a circuit of muscle about the mouth of the infenoi vena cava The patient had auricular flutter, and it is conceivable that the main path of the conti action wa\e was this ring of aberrant muscle


Seveial varieties of lemnants of the \enous valves of the embiyo occur There are two main groups of anomalies, those with and those without defective interatrial septums I have described those without a defective septum

The literatuie contains reports of twenty-two acceptable examples of that anomaly known as Chian’s netwoik, including Chian’s oiiginal eleven cases To these I haA^e added four more The designation, Chian’s netAvork, should be confined, probably, to those leticula in connection Avith the eustachian and the thebesian valves Avhich haA^e threads attached in the upper region of the atrium, neai the crista terminalis, or to the interatrial septum in the region of the tuberculum loweri

Such reticular formations as have been desciibed are usually not of clinical significance In a certain number, hoAvcA^er, an increased facility for the formation of thrombi on the threads of the network is noted In the literature, five instances are recorded in AAdiich such thiombi Avere

present, and in one there was no doubt that the thrombus was the cause of fatal pulmonary embolism In this series were four cases in which thrombi were found in connection with the eustachian or the thebesian valve, all apparently antemortem thrombi It is possible foi a person to succumb to pulmonary embolism the source of which is a thiombus formed on one of these networks Paiadoxically, such a network, by ensnaring an embolus fiom some vein, may prevent fatal pulmonary embolism

A theoretical point to be considered is the possible lelationship of these networks to aunculai fibrillation or auricular fluttei