THE SINO-VENTRICULAR SYSTEM AS DEMON- 

 STRATED BY THE INJECTION METHOD 



M. R. KING 



From the Division of Anatomy of the Stanford Medical School 



SIXTEEN FIGURES (FIVE PLATES) 



The investigation described in the following pages was begun 

 as a medical thesis. The first part of the investigation was 

 merely a confirmation of work done by Lhamon '11 on the 

 sheath of the sino-ventricular bundle. Since Lhamon's main 

 conclusions were readily verified an extension of his work was 

 undertaken, the results of which are here set forth. 



It seems that the earliest record of any discovery of a muscu- 

 lar connection between the atria and ventricles of the heart, is 

 that of Paladino in '76,^ who, according to Retzer '04, is referred 

 to by Bardeleben '76 as having found that ''die Vorhofsmusku- 

 latur endet nicht an den Annuli fibro-cartilaginosi, sondern geht 

 grossen Theiles in die Ventrikelwand und die Papillarmuskel 

 welter." This rather indefinite statement had to serve for a 

 description of the connecting link between the chambers of the 

 heart until Gaskell '83 demonstrated that, in cold blooded ani- 

 mals, the auricular musculature is connected with the sinus 

 musculature on the one hand and with the ventricle on the 

 other. Since this connection was less easily demonstrated in 

 the mammalian heart ten years elapsed after Gaskell's work 

 before the muscular connection between the atria and ventricles 

 of the heart of warm blooded animals was found. 



Kent '93 found a definite muscular connection between atrium 

 and ventricle in new born rats. This connection gradually 

 became less evident in rats of greater age and in the adult Kent 

 found only a few muscle strands. In the same year His, Jr., 



1 Through Professor Meyer I am enabled to call attention to the statement of 

 Prof. Giovanni Paladino in the Anatomischer Anzeiger. Band 46, 1914 "Ancora 

 per una questione di priorita a propositodel fascio atrio-ventricalare del cuore." 



149 



THE AMERICAN JOURNAL OP ANATOMY, VOL. 19, NO. 2 

 MARCH, 191G 



