THE SHEATH OF THE SINO-VENTRICULAR BUNDLE^ 



RUSKIN M. LHAMON 



Assistant Professor of Anatomy, Philippine Medical School 

 From the Anatomical Laboratory of Stanford University 



FIVE FIGURES 



The present investigation, undertaken at the suggestion of 

 Professor Meyer, is concerned chiefly with certain aspects of the 

 connective tissue sheath around the atrio-ventricular bundle, 

 or, as suggested by Retzer, the sino-ventricular bundle. As 

 this sheath has recently been mentioned and described to a 

 greater or less extent by many investigators, it is hoped that the 

 present communication will be of some interest. 



A review of the literature upon this subject will be given only 

 so far as the connective tissue sheath is concerned. Kent in 

 1893, noted a considerable development in the region of the auri- 

 culo-ventricular groove. In 1906, Tawara while recognizing 

 the Purkinje fibers as the branchings of the bundle, stated that 

 the bundle and its branches were everywhere isolated from the 

 cardiac muscle by connective tissue up to the point where the 

 transition into muscle cells takes place, and that at this point 

 also a transition of the connective tissue sheath into perimysium 

 occurs. Keith and Flack in 1906, Fahr in 1908, and Moncke- 

 berg in 1908, were impressed with the fibrous sheath and con- 

 firmed Tawara's findings. De Witt in 1909, while making dis- 

 sections of the bundle and its branches preparatory to reconstruct- 

 ing it, noted that she could not remove the sheath because of the 

 danger of breaking the strands of the bundle in many places 

 along the finer branches and at the region of the nodal points. 



x It is believed that this is the first application of the injection method t<> the 

 demonstration of the ramifications of the conductive system. These results are 

 so easily obtained and give such a complete picture of the system, especially in 

 the left ventricle, that after test ing it the editor cannot refrain from thus calling 

 attention to the value of the method. 



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