70 LABORATORY MANUAL OF ANTHROPOMETRY 



devised instruments, certain important internal landmarks may be 

 reached and located through the occipital foramen without injuring the 

 specimen. Furthermore, the development of various forms of goni- 

 ometer, and the establishment of a fixed horizontal, and other means for 

 a precise orientation, have introduced methods of measuring many of 

 the most essential angles directly upon the skull. 



There is thus usually left to the operator in determining a given angle, 

 a choice of several methods, but where a craniogram is available it will 

 often be found very convenient and practical to draw the angles to be 

 measured upon it, and then measure them on the paper by means of a 

 transparent protractor. This procedure is so very available, in fact, 

 that it offers a serious temptation to the investigator to try any angles 

 that suggest themselves, with the hope that they may prove useful or 

 even reveal some unexpected and significant relation that has escaped 

 the eye. 



The following angles have either already been extensively used with 

 success in showing important difference, or are believed to have some 

 chance of success in the future. As some angular measurements are very 

 old, older in fact than any linear measurements, the most of these have 

 now become classical by use, and are of first importance. 



1. Metopic or frontal profile angle. This is the angle of inclination of 

 the nasion-metopion line to the FH, and is best measured direct by the 

 stationary goniometer. The metopion, the point in the median line 

 crossed by the line connecting the two frontal eminences, is first ascer- 

 tained as accurately as possible, and marked on the skull surface by a 

 pencil. Then, with the skull oriented exactly on the FH, the two points 

 of the goniometer are placed, the one on the nasion, the other on the 

 metopion, and the angle read off in the usual way. 



The exact apex or center of the two frontal eminences is more easily 

 ascertained by the finger, rubbed over the surface, than by the eye; or 

 when, as in an espcically smooth forehead, even this method is insuf- 

 ficient or uncertain, the point in the median line exactly one-third of the 

 distance from nasion to bregma is taken as the metopion. GO. 



2. Frontal angle of Schwalbe. A somewhat more practical frontal 

 profile, readily drawn and measured upon a craniogram, and serving 

 the same purpose of the previous one, is that devised by G. Schwalbe 

 and used first in his studies of Pithecanthropus erectus.* 



As first used this angle was formed by the glabella-inion line with 

 one drawn upward from the glabella and tangent to the most projecting 

 point in the frontal profile curve; but in his later use of this Schwalbe 

 substituted nasion for glabella, and the angle now used is fr-n-i, fr being 

 the indefinite free end of the frontal tangent. CG. 



3. Frontal inclination angle ( = "Bregma angle" of Schwalbe). This 

 has the advantage over the previous angle in the accuracy of the points 



* Zeitschr. fur Morphol. und Anthropol. Bd. 1, 1899, p. 142. 



