506 
The Measurements of the Pelvis 
3. Formulae have been obtained for finding the obstetric conjugate and the 
transverse diameter on the dry pelvis. The former may be found best from the 
diagonal conjugate, singly or combined with the antero-posterior diameter, 
the height of the hip bone, or the pubic height. The transverse diameter is 
found from the inter-cristal diameter, taken by itself or combined with one or 
two of the following: inter-spinous diameter, antero-posterior diameter, height 
of hip bone. The formulae were tested and found to give good results for the 
modern English female pelvis. 
4. Pelves were measured dry and after immersion in water to study the 
effects of moisture. All the diameters and the heights of the hip bones are 
slightly greater in the moist than in the dry pelvis. 
5. The way in which the soft tissues affect the measurements has been 
pointed out. The thickness of the tissues over the bones bounding the internal 
diameters is almost negligible. 
6. Finally formulae have been arrived at for finding the obstetric conjugate 
and the transverse diameter in the living subject. The simplest of these, for the 
obstetric conjugate, are approximately 
0 = -98D-l-68, 
C = (D-1)-^H, 
and, for the transverse diameter, 
T = -31K + 471, 
T = i(K + 10) + 1 L(H + 10), 
where D is the length of the diagonal conjugate, K that of the inter-cristal 
diameter, and H the height of either hip bone. 
In conclusion I wish to thank Prof. Karl Pearson and all those who have so 
generously come to my help — Prof. Symington for placing his diagrams at my 
disposal, Prof. Thane and Dr Derry for the loan of pelves, Dr Derry and Dr 
Braxton Hicks for their measurements on post-mortem subjects, and Mr Soper 
for the useful little instrument with which most of these measurements were 
made. To Prof. Pearson is due whatever merit this work may possess. It has 
been carried out under his guidance without which it could never have been 
attempted. 
APPENDIX I. 
Measurements of five pelves used for testing formulae. I and II ancient 
Egyptian female. Ill ancient Egyptian male. IV modern English female. 
V modern English male. In IV and V the bones were connected together by 
the ligaments. 
