OSTEOMETRY; THE MEASUREMENT OF THE BONES 65 



The frontal and occipital arcs admit each of a separation into two 

 parts, the proportions of which are of significance. The frontal arc is 

 divided by the supraglabellare into a pars glabellaris and a pars cerebralis; 

 the occipital is divided by the inion into an upper and a lower scale 

 (squama). In each case the various measurements of arcs and chords 

 may be compared by the use of indices and give details concerning the 

 contour of the bones in question. Those which concern the forehead are 

 of especial significance. 



12. Indices of the frontal curvature 



. chord of pars glabellaris [g - sg] X 100 

 12 (a) Glabellar curvature index ,. r-^ 



arc ot pars glabellaris 



[This gives the amount of projection (bulging) of the supra- 

 orbital region, and is especially useful in" comparing the 

 Neandertal and other prehistoric types with the present species; 

 also in the study of Australians, and other primitive races]. 



12M Cerebral curvature index ch rd f pafS cerebralis ^ ~ 6 1 X 10 



\U } l w /c/t'C//Ci6 t/M'/C'til'M'/t/ C'/C'tC'C/*!/ P 11* 



arc of pars cerebralis 



12() Glabello-cerebral index ch< "? ? &***> fr-* 1 X 100 



chord of pars cerebralis [sg b] 



13. Indices of the occipital curvature 



. , chord of upper scale [I i] X 100 

 13(o) Upper scale cunature index - ^- j_ 



chord of lower scale [i o] X 100 

 13(6) Lower scale curvature index- arc of lower scale 



13(c) Upper and lower scale index (chords) 



chord of lower scale [i o] X 100 

 chord of upper scale [Z i] 



. arc of lower scale X 100 

 13(d) Upper and lower scale index (arcs) arc of upper scale 



[The two last indices give the relative position of the inion.] 



14. Index of the occipital foramen 



breadth of foramen occipitale [216] X 100 

 length of foramen occipitale [21a] 



[Like other indices, this gives the shape rather then the size. 

 These indices may be classified as narrow, below 82; average, 

 82-86; and broad, from 86 on.] 



II. INDICES OF THE FACE* 



_. i , , . 7 . nasion-gnathion line [11] X 100 



15. Total facial index rr - r ,. u ro1 



bizygomatic breadth [8] 



*Cf. Marie Sawalischin, in Archiv f. Anthropologie, Bd. 8, 1909., pp. 298-307. 



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