18 A NEW TYPE OF BRACHYPHALANGY IN MAN. 



50 is from a radiograph of the foot of a brachyphalangous member of 

 the family. It demonstrates the typical condition and needs no further 

 description. 



The investigation of the so-called normal individuals within the 

 affected family soon demonstrated that the malformation also mani- 

 fests itself under another and markedly different somatic type. Several 

 examples of this type are given in figs. 13, 19-25, and 31-36. Examined 

 from the dorsal surface, the hands in some cases would easily be 

 regarded as normal (figs. 13, 23, 31, and 35); in other cases a slight 

 shortening of the indices is clearly recognizable. An inspection 

 from the volar surface shows that here also the shortening is 

 restricted to the second phalanx of the indices. This is indicated by 

 a shortening of the distance between the middle and the distal grooves 

 of the skin. 



Sometimes this shortening is very marked and can not be overlooked 

 (figs. 20, 21, and 34) ; but in other cases it is so slight that even a careful 

 comparison with normal hands leaves it doubtful whether the abnor- 

 mality is present or not (figs. 13, 24). Index fingers of this type often 

 seem to be a little narrower around the second segment, which makes 

 the third segment look a little club-shaped and thickened (figs. 9, 34) . 

 They are always straight, a bent condition (as described above) never 

 being observed. 



It will be easily understood that the shortening of the distance 

 between the second and third grooves as a measure is very inexact. 

 It is therefore in many cases very unsatisfactory as a diagnostic 

 feature, and a control by radiographs is absolutely essential. 



The radiographs in most cases clearly show that the second index 

 phalanx is shortened and sometimes a little narrower, but we have 

 cases where it is very hard to tell whether a shortening is actually 

 present or not. The length of the finger bones is very variable in nor- 

 mal hands, and only a very careful analysis of the measures obtained 

 from the radiographs permits certain conclusions to be drawn. This 

 point is discussed on pages 51-55. It may here be stated only that this 

 analysis in the great majority of the more doubtful cases clearly shows 

 that a brachyphalangy of the second index phalanx is present, but we 

 have a few cases where the measurements fall within the limits of 

 extreme variation in normal hands. Here a conclusive decision can 

 be reached only through the genetical test obtained from the examina- 

 tion of the offspring. 



With regard to the form of the shortened phalanx, it will be noticed 

 in the radiographs that the typical phalanx form is retained. The 

 radiographs from children's hands show that the epiphysial cartilages 

 are present in the affected phalanges. 



We have in our material no cases representing an intermediate con- 

 dition between the two types just described. We are evidently dealing 



