52 LABORATOKY MANUAL OF ANTHROPOMETRY 



the external surface, being held down from point to point by the finger 

 or thumb. The same technique is followed in the two following. TM. 

 23. Transverse cranial arc; taken from the projecting ridge at the 

 base of the zygoma of one side, directly above the auditory opening, 

 over the top of the skull to the corresponding point upon the opposite 

 zygoma. The line must run in a single plane, and must include the 

 bregma. TM. 



23. (bis). Horizontal circumference; measured around the head, over 

 the superciliary ridges in front, and the occipital protuberance behind, 

 in such a manner as to get the maximum circumference, while keeping 

 the line in practically a single plane. TM. 



24. Cranial capacity; this is not a linear measurement, but the usual 

 measurement of the cubic capacity of the interior cavity of the skull. 

 The Committee made no decision concerning the exact method to employ 

 relative to the material to be used, etc., but recommended the employ- 

 ment of several control skulls, that is, either actual crania or artifically 

 constructed cavities of known capacity, which are to be used frequently 

 (between each two or three measurements) to test the method; also, 

 whenever possible, it recommends the use of water in a rubber container. 



B. THE MANDIBLE 



25. Bicondylar breadth; the greatest breadth between the lateral 

 surfaces of the two condyles. . SC or RC. 



26. Bigonial breadth; the greatest breadth between the summits or 

 apices of the two angles of the jaw, the gonia. SC or RC. 



27. Length (height} of ramus; from the upper surface of the condyle 

 to the apex of the angle (gonion). As this latter point is frequently 

 difficult to determine with precision, take as this apex the point of 

 intersection of the two lines drawn along the borders of the two parts 

 involved, body and ramus. This measure may be made in a practical 

 way by letting the mandible rest naturally upon a table, on its lower 

 border, and measure from the surface of the table, along the posterior 

 border of the ramus to the highest point of the condyle. SC. 



28. Breadth of ramus. 



(a) Minimum breadth; the least distance between anterior and 

 posterior borders. 



(6) Maximum breadth (tentative); the breadth across the upper 

 end of the ramus, from coronoid process to the posterior 

 border. The two legs of the slide compass (or rod compass) 

 are placed so as to receive the ramus, one leg applied along 

 the posterior border, the other tangent to the anterior border 

 of the coronoid process. SC or RC. 



29. Symphyseal height; the distance between the alveolar and the lower 

 borders of the mandible, measured at the symphysis, in the median plane; 

 the infra-dentale-gnathion line. SC. 



