Franklin P. Mall 399 



and every specimen verifies the statement of Langer and Briicke, that the 

 whole wrist falls to the outside of the sagittal plane of the humerus when 

 the forearm is extended and pronated. The assertion of Stratz that in 

 this position the line falls in the middle of the wrist is absolutely incor- 

 rect. Furthermore, his diagram (Fig. 67) which is apparently based 

 upon Merkel's normal figure, is also incorrect, for Stratz's own copies of 

 Merkel's figures (Figs. 31 and 32), as well as the originals, coincide with 

 Briicke's as regards this point. 



With the elbow extended the average deflection of the styloid process 

 of the ulna from the sagittal plane of the humerus is 11° from my 

 measurements. The average length of the ulna from the axis of the 

 elbow to the styloid process is 258 mm. With these two measurements 

 11° equals a chord about 5 centimeters long, so the styloid process deflects 

 normally 5 cm. or about the width of the wrist. Therefore, with the 

 arm extended the wrist should fall outside of the sagittal plane of the 

 humerus in both supination and pronation. In both positions the 

 styloid process falls about 5 cm. to the outside of the sagittal plane of 

 the humerus and in pronation it passes through the styloid process of 

 the radius. In the extended arm all of the wrist, or at least its greater 

 part, falls lateral to the sagittal plane of the humerus in both pronation 

 and supination. This marked deflection, more so in my records than is 

 stated by any author, is no doubt due in part at least to a racial differ- 

 ence, for 70 of the arms are from negroes and but 19 from Europeans. 

 A glance over the tables shows that some difference does exist, which I 

 shall now consider. When the differences in deflection are grouped for 

 every 5°, as was done when discussing the motion of the elbow, nothing 

 definite is noted, and when they are grouped under single degrees the 

 figures scatter so much that it is again difficult to see any marked result. 

 The negro male, however, shows some 3° greater lateral deflection in the 

 movement from flexion to extension than does the European male. The 

 difference between the European male and female is much greater, but 

 the number of cases are so few that this also cannot be considered. It 

 would indeed be remarkable if more records showed that the European 

 female had the greatest lateral deflection and that the European male 

 the least, that of the negro lying between. If it should prove to be so, 

 then artists have secured their ideal straight arm of females from the 

 males and infants ' where the lateral deflection is the least. 



The racial difference becomes more marked when the total amount of 



' Braune and Kyrklund state that the angle of the humerus in infants is 

 much less than in adults. 



