THE HUMAN STERNUM 

 B. Variations in Form 



39 



(a) Suprasternal Ossifications 



From an examination of two hundred and thirty-six foetal sterna 

 between three and nine months (p. 20), only two examples were obtained 

 of additional suprasternal cartilages (o*8 per cent.) In a female sternum of 

 six months, two ovoid cartilages occur upon its upper border, fused together, 

 but separate from the presternum. In another female sternum of nine 

 months, two cartilages occur separate from each other, and fused with the 

 upper border of the presternum (PI. VI, Fig, 43A, b). 



Since the above investigation was published the statement has been 

 madc^' that such conditions are much more common than appeared 

 from my observations. To verify or reverse my previous statement, 

 Dr. W. H. Broad, Robert Gee Fellow of Anatomy in the University of 

 Liverpool, has examined for me fifty-four foetuses, with, however, a 

 completely negative result. None of the sterna presented suprasternal 

 cartilages. The particulars of age and sex of the foetuses examined were : — 



With this controlling observation one appears to be justified in 

 regarding the appearance of these additional cartilages as a rare and 

 anomalous condition. 



