H. Drinkwatkr 29 



In adult life this piece of gristle becomes ossified, and with the 

 shaft and epiphysis forms one bone. 



Fig. 9 shows the epiphysis at the base of the first phalanx and one 

 at the base of the third but the second phalanx is seen to be without 

 any epiphysis except in the case of the middle finger. 



This absence of epiphysis accounts for a good deal of the shortening 

 of the finger, but not for the whole of it ; for it is obvious that the 

 shaft of the bone is of less than normal length and the first and third 

 phalanges are also slightly shorter than they should be. 



CT) 



Fig. 8. Outline of bones (not fully ossified) of brachydactyloos 

 finger of a youth. 



1. First phalanx with epiphysis (ep.) at base. 



2. Second phalanx without epiphysis. 



3. Terminal phalanx with epiphysis (ep.). 



There are three factors producing the shortening of the second 

 phalanx : 



(1) The slight shortness of the shaft of the bone. 



(2) The absence of the epiphysis. 

 These have already been referred to, but 



(3) There is still another factor and to this is perhaps attribu- 

 table the chief share in the production of the shortening. 



I have already drawn attention to the cartilage or gristle between 

 the shaft and the epiphysis. So long as this cartilage remains the bone 

 can and does increase in length with the growth of the individual but 

 when it has become ossified, then no further growth, in length, of the 



