16 A NEW TYPE OF BRACHYPHALANGY IN MAN. 



IV. GENERAL DESCRIPTION OF THE BRACHYPHALANGY 



STUDIED. 



The hands of the brachyphalangous individuals which first came to 

 our knowledge are of a very characteristic aspect (figs. 4, 7, 10). While 

 the middle part of the hand and all the other fingers are normal, the 

 index finger appears strikingly shortened. In the most pronounced 

 cases this finger as a whole is only a little longer than the basal seg- 

 ment of the third finger. Inspection from the dorsal side of the hand 

 shows at once that the shortening is limited to the middle segment of 

 the index. The basal segment is normal and so is the distal one, and 

 in all cases the nail is quite normal. 



Seen from the volar surface, it is noticed that the index fingers in the 

 most pronounced cases have only two instead of the normal three 

 grooves. This is, for instance, true of the hands represented in fig. 

 4 and fig. 7. In other cases there are three grooves, but the distance 

 between the two distal ones appears very markedly shortened when 

 compared with the same distance in normal hands. In one case there 

 are three grooves on one index and only two on the other (fig. 12). 



It will easily be understood from the photographs that a superficial 

 examination would lead to the conclusion that the middle segment of 

 the finger is entirely missing, an opinion which is general within the 

 family. But palpation quickly makes it clear that the middle phalanx 

 is present, even if only as a rudimentary sesamoid bone. This mal- 

 formed phalanx is often subluxated to the ulnar side of the joint, 

 where it can be felt, a relation which explains a characteristic feature 

 in the aspect of many of the affected index fingers; for, as will be seen 

 from several of the photographs, the brachyphalangous index is not 

 straight, but slightly bent, the basal phalanx forming a slight angle 

 with the terminal one, the latter pointing in a radial direction. 



It is typical that this bent condition is most often met with on the 

 right hand, while the left brachyphalangous index is generally straight. 

 This relation is explained by the information frequently obtained that 

 the mothers of the affected children always tell them to pull and 

 straighten the index fingers. The children, being right-handed, are 

 more energetic in their treatment of the left index, and the result just 

 described is obtained. The bent condition of the brachyphalangous 

 finger is in several cases very marked, and the brachyphalangy is often 

 referred to by the members of the family as ''crooked fingers." 



The brachyphalangy seems not to affect the use of the hand in any 

 particular way. Family members of the most different occupations 

 all state that they can easily do any kind of work with their hands. 

 The flexion of the indices is, however, limited when compared with 

 normal hands, and in some cases it is easy to produce a subluxation of 

 the terminal phalanx. 



