116 LABORATORY MANUAL OF ANTHROPOMETRY 



termini of a line frequently have some obstacle between them which has 

 to be reached around in order to obtain a straight measurement. Again 

 the slide-compass and the rod-compass are practically the same thing 

 in two sizes, also for convenience; and these with the clamp-on goni- 

 ometer the tape, and the anthropometer, of which the rod-compass is an 

 adjustment, are all that is needed both for bones and the living, for all 

 anthropometric uses except certain special work. 



Aside from the sub-pubic angle, the difference in the value of 

 which in the two sexes has long been known, the ossa coxae with the 

 sacrum exhibit other marked sexual differences, which may usually be 

 relied upon in sexing a skeleton. These latter are especially practical 

 when applied in the field during excavation, or in the case of incomplete 

 skeletons, as they concern the single parts of which the girdle is composed 

 and consequently do not require to have the pelvis put together as is the 

 case with the subpubic angle. 



The following are the most pronounced of the sex-determining char- 

 acters of the separate ossa coxae: * 



1. The curve of the iliac crest. This is higher and more abrupt in the 

 male; or, in other words, the outline presents the arc of a much smaller 

 circle. It also turns down more abruptly dorsally. 



2. The shape of the sacro-sciatic notch. This is narrow and deep in the 

 male; shallow and wide in the female. 



3. The sulcus paraglenoidalis s. praeauricularis. This is a groove, 

 which runs over the inner surface of the ilium, just posterior to the au- 

 ricular surface, and parallel to its posterior border. It is very, variable 

 in its appearance and occurrence, being generally absent in males, and 

 present in females, with exceptions both ways. When well developed 

 it is 2 cm. or more in length, and runs over the dorsal margin of the bone, 

 so that it may sometimes be seen upon the outer side.f 



4. The acetabulum. 



(a) This is larger in males; smaller in females. 

 (6) In females it looks more forwards; in males more laterally. 

 This character can be seen only in the complete pelvis. 



Sacrum % 



I. MEASUREMENTS 



1 . Mid-ventral curved length; the length of the median line, drawn along 

 the ventral surface, from the median point in the anterior or margin 



* There are also certain sex differences in the sacrum, which are noted in their 

 proper place, below. 



f For a recent discussion of the sulcus paraglenoidalis (praeauricularis) cf . DERBY, 

 in Journ. Anat. and Physiol, Vol. 43, 1909, pp. 266-276; see also LOHR, in Anal. Am., 

 Bd. IX, 1894. 



t Cf. RADLATDER Beitrage zur Anatomie des Kreuzbeines. Morphol. Jahrs., 

 Bd. 38, 1908, pp. 323-447. This work was done at Zurich under Rudolf Martin, 

 and is a complete analysis of the sacrum, treated anthropometrically and racially, 

 according to the newest methods. The work may be taken as a standard and is 

 largely followed here. 



