H. Drinkwater 31 



bone can take place at this point. Now this layer of cartilage does 

 not become ossified in the average individual until about the twentieth 

 year, so that until that age the phalanx can and does increase in 

 length. If however ossification occurs prematurely, then the growth 

 of the bone will be arrested and a permanent shortening will be the 

 result. This is exactly what has happened in this family especially in 

 the first and little fingers. In Fig. 5 the second phalanx is seen to be 

 short in all the four fingers. This is the hand of a woman (No. 9). 

 Fig. 10 shows the hand of her son (aet. 14). Here there is no sign of 

 the epiphysis of the second phalanx except in the middle finger where 

 it has already united to the shaft. In the other fingers it has never 

 been present or has united during infancy. The abnormality in this 

 boy will therefore be an almost exact repetition of the mother's. 



These cases represent the extreme type of deformity in this family. 



Fig. 11 shows a modification of this type in the adult. It is the 

 hand of No. 12. 



The second phalanx is seen to be much more shortened in the 

 index and little fingers than in the middle and ring fingers. Why is 

 this? 



I think the explanation is furnished by the radiograph (Fig. 12), 

 which shows the hand of her dauorhter aged 8. 



In this girl's hand there is an apparent absence of the epiphysis in 

 the fourth finger, and in the index finger ankylosis has already occurred, 

 whilst in the middle and ring fingers the epiphysis is still separated by 

 cartilage. 



When growth is complete this hand will be like the mother's Avith 

 the second phalanx much shorter in the first and fourth fingers than in 

 the second and third. 



In another child of No. 12 aged 2 years the ossification of the 

 cartilage has already occurred in the first finger (Fig. 13). 



The third factor concerned in the production of shortening of the 

 middle phalanx is, therefore, premature ossification of the cartilage 

 intervening between the shaft of the bone and its epiphysis. 



The essential feature of the abnormality in No. 1 family was stated 

 to be "an absence of the epiphysis at the base of the second phalanx" 

 with subsequent ankylosis of the second to the first phalanx, so that 

 we have in the present family an abnormality which is essentially the 

 same developmentally but stopping short of ankylosis. 



The second phalanx in the middle finger is less affected than in the 

 others and this was also a characteristic of No. 1 family. 



