30G 



A Composite Study of the Subclavian Artery in Man 



Section A. — Types of Eamification, 



The mode of ramification of the subclavian artery is found to be 

 divided into five types, depending upon the origin of the large branches. 

 The distribution of these branches is practically the same in all cases. 



Type I (Fig. 3) occurs in 30% of the cases classified, 22% being on 

 the right side of the body and 8% on the left side. In this type the 

 vertebral and internal mammary arteries rise from Part I ; the inferior 

 thyroid and suprascapular arteries rise from a common trunk which 

 comes from Part I, and between these two arteries rises the superficial 



ACR 



RATC 



R.D.T.C. 



Fig. 3. Type II, occurring in 27% of the specimens, 22fo on the left side, and 

 5% on the right side of the body. For index to lettering see Fig. 1. 



cervical artery ; the ascending cervical artery rises ' from the inferior 

 thyroid; and the transverse cervical artery and the costo-cervical trunk 

 rise from Part II. Each of the branches often has a separate origin. 

 There are in this type 19 male negro subjects, 2 female negro subjects, 

 5 male white subjects, 2 female white subjects, and 4 subjects in which 

 the sex and race are not determined. 



Type II (Fig. 3) is found in 27% of the cases classified, 22% being 

 on the left side of the body and 5% on the right side. The vertebral 



