36 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 92 



ADOLESCENTS COMPARED WITH ADULTS 



We shall at this point present facts which are of the utmost interest, 

 and to which thus far there are no close parallels in anatomy and 

 anthropology. 



In dealing with the fetal and juvenile femora it was seen that the 

 hypotrochanteric fossa began to form in some bones as early as 

 the fifth month of the fetal life and that thenceforth it gradually in- 

 creased, both in incidence and development, throughout the growth 

 period. The long stretch of time during which it continued to originate, 

 as well as to enlarge, is in itself a phenomenon of no small interest. 



By the latter part of adolescence, in all the groups whose bones 

 were available for the study, traces of the fossa to a pronounced hol- 

 low, were seen to have become almost universal. We now pass to 

 the adult material, where we encounter a distinct surprise. The records 

 of the frequency and spaciousness of the fossa in the adults show 

 radical differences from those in the preadult life. These differences, 

 moreover, are found in all the groups, and they cannot possibly be 

 due either to chance or error. They are shown in the next table : 



H y potrochanteric Fossa in Adolescents and in Adults Compared (Both Sexes, 



Both Sides) 



Group and no. of femora 



U. S. Whites: 



Adolescent (26) . 

 Adult (1,000) . . 



U. S. Negroes:" 



Adolescent (100) . 

 Adult (100) 



Old Eg>'ptians: 



Adolescent (35) . 

 Adult (200) . . . . 



Old Peruvians: 



Adolescent (79) . 

 Adult (868) . . . . 



N. A. Indians: 



Adolescent (279) . 

 Adult (3,890).... 



Eskimos: 



Adolescent (99). 

 Adult (718) 



None 



15-4 

 32- 



2.9 

 20.5 



6.3 

 24.4 



2,9 

 12.2 



3- 

 10.4 



15 4 

 18.2 



16. 

 16. 



12.5 



2.5 

 13 7 



2.5 

 19 5 



3- 

 18.7 



Small 



but 



distinct 



154 

 20.- 



7- 

 23- 



14-3 



25 - 



8.9 

 36.5 



6,1 

 32.2 



10. 1 



24. 1 



Mod- 

 erate 



Percent 



34-6 

 15-8 



16.- 

 II .- 



14 3 

 18.- 



II. 4 

 16.6 



17.6 

 20.7 



18.2 

 22.3 



Medium 



Percent 



II 5 



19- 



17- 



28.6 

 17- 



329 

 7.6 



35-8 

 133 



35-4 

 195 



Above 

 medium 



Percent 

 3-8 

 2.6 



22.9 

 3 - 



21 5 

 0.9 



25 I 

 1-5 



20.2 

 3-3 



Pro- 

 nounced 



Percent 

 3-8 

 0.2 



17. 1 

 4 - 



16.5 

 0.2 



10. J 

 0.6 



10. 1 

 1.7 



" Series least satisfactory: among adolescents a very large proportion of subadults (19-21 years) 

 and a good many mixed-bloods; adults practically all full-blood. 



