334 A Second Brachifdactylous Famihj 



unossified, the bone can increase in length, but after its ossification 

 further growth does not occur. 



The disc seen in some of the radiographs at the base of the terminal 

 phalanx looks very much like an epiphysis, but is really the second 

 phalanx in a very abortive condition. 



In some instances in children there is only one piece of developing 

 bone visible between the shafts of the third and first phalanges ; 

 normally, three can be seen : namely, (1) the epiphysis of the third, 

 (2) the shaft of the second, and (3) the epiphysis of the second phalanx, 

 and it is only j)ossible by a comparison of several hands to say what 

 this single bone represents. I believe it always represents the shaft of 

 the second phalanx. 



In no single instance does the radiograph show the presence of an 

 epiphysis at the base of the second phalanx. 



It is thus clear that there is no real absence of the second phalanx in 

 any individual, but merely a rudimentary condition, and that at a certain 

 stage of development there is a union of this tuith the terminal phalanx. 



" The essential feature of the abnormality apparently consists in an 

 absence of the epiphysis at the base of the second phalanx. It is 

 possible that the epiphysis is also missing, in some instances, from the 

 third phalanx, and that the two phalanges (second and third) consist at 

 first of a single piece of cartilage." 



Premature union of shaft and epiphysis is of general occurrence in 

 this family. Such union should nut occur until about 20 or 21 years 

 of age. In No. 41, a girl of 15, it is already comjjlete, and the radio- 

 graph would pass for that of an adult hand. In this instance, moreover, 

 the union is not recent, for the epiphyseal lines are already almost 

 entirely obliterated. The hand of the boy (PI. XV, No. 31), aged 8 years 

 and 4 months, shows a very interesting peculiarity. The epiphysis of 

 the third phalanx, though still separate from its own shaft, has already 

 united with the shaft of the second phalanx in the first and little 

 fingers. This seems to point strongly to the opinion expressed above, 

 that these two phalanges are sometimes represented by only one piece 

 of cartilage. This premature union of the shaft and epiphysis is no 

 doubt one great factor iu, producing the characteristic shortening. 



" The index and fourth fingers seem more aberrant than the second 

 and third, as they (the former) never show the middle phalanx as a 

 separate bone in the adult." In PI. XV, No. 27 (aet. 19), the union has 

 occurred in the little finger : in the index finger the union is not yet 

 complete, but it is evidently taking place. 



