168 DESCRIPTION OF FIGURES OF SKULLS. 



it fails thus to coincide with the vertical line chosen for placing- 

 the skull in for the purpose of drawing, it does coincide very nearly 

 with the line which might be drawn across the external surface of 

 the cerebral hemisphere for limiting posteriorly the area which 

 is most favourably conditioned as to irrigation with arterialised 

 blood. The segments therefore into which it divides the line of 

 extreme length may be held to correspond respectively to more 

 and to less favourably nourished and actively operating segments 

 of the cerebral hemisphere, and the statement of their relative 

 proportions as expressed in the ' Antero-posterior Index' assumes 

 considerable importance. 



The indications as to prognathism and its absence furnished by 

 the 'maxillary index' of Virchow and the 'gnathic index' of Busk 

 ( f Journal Anthrop. Instit.' London, Jan. 1874, p. 496) are both 

 easily obtained by comparison of the three measurements, (a) of 

 the basi- cranial axis taken from the middle of the anterior border 

 of the occipital foramen, the 'basion' of Professor Broca, to the 

 fronto-nasal suture ; (b) of the ' basio-subnasal ' line measured 

 from the 'basion' to the base of the nasal spine; and (c) of the 

 ' basio-alveolar line ' measured from the ' basion ' to the edge of 

 the alveolar process of the upper jaw. A fourth facial measurement, 

 that of the length from the fronto-nasal suture to the edge of the 

 alveolar process of the upper jaw, which may be called the * naso- 

 alveolar' line, together with the three others just given, enables us 

 to construct two ' facial triangles.' In some cases where the 

 anterior margin of the foramen magnum has been wanting, the 

 facial angles, with apices respectively at the base of the nasal spine 

 and at the fore-edge of the alveolar border of the upper jaw, have 

 been taken by Professor Broca's ' Nouveau Goniometre,' described 

 and figured in the 'Bullet. Soc. Anth. Paris,' t. v. i M Serie, 1861, 

 pp. 943-946, or in his collected 'Memoires d'Anthropologie,' torn. i. 

 pp. 106-109, 1871 K 



The stature has usually been calculated from an estimate of 

 the length of the femur as being 27*5 to 100 of the entire length 

 of the body. By another method, that of adding the lengths of the 

 femur and tibia together, multiplying by two, and then adding 

 an inch for the calcaneal integument, we obtain sometimes an 



1 For alveolar prognathism and its linear measurement, see Topinard, 'L' Anthropo- 

 logic,' p. 303, 1876, and Sasse, ' Archiv fitr Anthropologic,' ix. p. 9, 1876. 



