DESCRIPTION OF BRACHYPHALANGY STUDIED. 17 



An inspection of the photographs represented will demonstrate that 

 the brachyphalangy is in general strikingly symmetrical if we dis- 

 regard the bent condition just mentioned. The difference in length 

 between the brachyphalangous indices of the same individual is never 

 very pronounced. 



With regard to the type of the brachyphalangous hand in general, 

 it has been found that some of the individuals have a rather clumsy 

 hand with fairly short fingers (figs. 4, 7), but this condition can not be 

 regarded as characteristic for the affected individuals only. Their 

 normal brothers and sisters may represent a similar type (fig. 1), and 

 on the other side we have cases where the brachyphalangy is present 

 in hands of a very slender type with long, thin fingers (fig. 18). 



These general statements concerning the type of the brachypha- 

 langy described are confirmed and made clearer by the study of the 

 radiographs. It will be seen from these that the brachyphalangy is 

 restricted to the second phalanx of the index, its form and size having 

 undergone a complete change. In many cases the shortening of this 

 bone is so pronounced as to leave merely a scarcely visible rudimentary 

 roundish bone, generally situated at the ulnar side of the articulation 

 established through the coming together of the distal articular surface 

 of the basal phalanx with the proximal of the terminal one (figs. 4, 7, 

 10). Every trace of the normal form of the second index phalanx has 

 disappeared; but we have no case in our material where the second 

 phalanx is entirely absent. 



In some cases the rudimentary second phalanx has one or two (figs. 

 39, 40) small articular surfaces for articulation with the other phalanges. 

 In the last case the radial part of the articulation is established through 

 the articular surfaces of the first and third phalanx, while at the ulnar 

 part they have adapted their form for articulation with the two oblique 

 articular surfaces of the rudimentary second phalanx. The articulation 

 shows in these cases a Y form in the radiographs (fig. 40) . Not always, 

 however, is the change in form so thoroughgoing. Figs. 42, 45, and 51 

 show how the brachyphalangous bone may retain its character of a 

 phalanx with two typical articular surfaces. The bone is thick and 

 lacks the narrower middle part, characteristic for a normal phalanx. 



A radiograph from a 12-year-old child (fig. 15) shows a total absence 

 of epiphysial cartilage and reveals the fact that the brachyphalangous 

 condition is brought about by a premature ossification of the cartilage, 

 resulting in a stopping of the growth in length. 



An examination of the feet of the brachyphalangous individuals con- 

 firms their statements that the feet are affected in exactly the same 

 way as the hands. We have made sufficiently numerous personal 

 examinations to conclude that the brachyphalangy shows a striking 

 vertical correspondence. Only the second phalanx of the second toe 

 is brachyphalangous. The other bones of the feet are normal. Fig. 



