ONTOGENY AND PHYLOGENY OF THE STERNUM 43 



work dominated the field that even in the latest editions of 

 Human Anatomy texts his work is alone mentioned, or at most, 

 a footnote is added to the effect that this view has of late been 

 questioned by some. 



However, there are at least two later views as to the origin of 

 the sternum. Pater son ('00, '02, '04), on the one hand, and 

 Whitehead and Waddell ('11), on the other, have propounded 

 theories which are at once contradictory of Ruge 's view and also 

 antagonistic to each other. Thus there are at the present time 

 three distinct and opposing theories concerning the origin of the 

 sternum, and it was with a view to clearing up this confusion 

 and also to give the prominence deserved to this later work that 

 the present investigation was undertaken. For while a study of 

 the papers representing these theories may not convince one of 

 the validity of any one of them as opposed to the others, the 

 latter two mentioned do point out very clearly that there are data 

 which Ruge did not consider; and further, that our commonly 

 accepted view concerning the origin of the sternum, held for 

 nearly forty years, must be greatly modified and possibly cast 

 aside altogether. 



2. Pater son's coracoidal theory 



Professor Paterson in a series of papers ('00, '02, '04) was the 

 first to attempt to overthrow Ruge's theory of the origin of the 

 sternum from the ventral ends of the ribs. His observations 

 were made upon the rat, rabbit, and man. He describes a single 

 median rudiment which is directly continuous with the mass of 

 cells destined to form the shoulder-girdle. From this median 

 mass two strands of cells grow caudally to form the sternal 

 bands. Whitehead and Waddell ('11) say, "thus in the final 

 analysis, according to Paterson 's view, the sternum is derived 

 from the shoulder-girdle." This seems an unwarranted state- 

 ment. It would be as correct to say that, according to Paterson, 

 the shoulder-girdle is derived from the sternum as to say, as 

 do Whitehead and Waddell, that Paterson makes the sternum to 

 be a derivative of the shoulder-girdle. What Paterson does 

 succinctly say is, "that the presternum and shoulder-girdle are 



