MUSCULAR ARCHITECTURE OF THE HUMAN HEART 255 



Fig. 16 Pig's heart cut open on its left side and tlien Ijoiled after which the papil- 

 lary muscles were torn out. A and P, anterior and posterior papillary muscles. A 

 muscle band from the right ventricle passes between them. The bundle X belongs 

 to the anterior papillary muscle. 



it enters at the locking point of the two horns of its vortex. If 

 now the strands of the anterior horn of the vortex of the left ven- 

 tricle are cut as they pass over the posterior longitudinal sulcus, 

 SLP, the interventricular strands are brought to light deep in the 

 septum as is well shown in figs. 3 and 8. By cutting through all 

 the muscle which connects the two ventricles in fig. 8, fig. 12 is 

 obtained. Here it is clearly seen that the interventricular bands, 

 IV, lie nearest the lumen of the ventricle, while the bulbo-spiral 

 bundle, C, and that forming the anterior horn of the vortex, D, 

 lie more superficially. The connection of the interventricular 

 strands is shown in fig. 15; this is from a distended heart which has 

 been macerated and fully dissected. It is seen that the inter- 

 papillary bands also extend upward in the right ventricle to end 

 in the membranous septum. 



Although the muscle strands are more intimately blended with 

 one another at the apex of the heart of the pig than in man, it has 

 been easier for me to follow the attachments of the papillary 



