MUSCULAR ARCHITECTURE OF THE HUMAN HEART 



219 



A' 



B' 



Fig. 1 Base of a well developed heart showing the course of the superficial mus- 

 cle fibers. A, A' {BS), origin of the superficial bulbo-spiral muscle; B, B', (SS) 

 origin of the superficial sino-spiral muscle. From X to A'' around the front of the 

 aorta indicates the coi^ise of t lie aortic septum. TR, posterior triangular field. 

 With the exception of ngs. 13 and 15 the figures arc tiaUiral size. 



