The Roentgenological Survey of the Pelvis *

With further experience in the application of roentgen technics to surveying the female bony pelvis has come increased knowledge of the architecture of this structure and of its relation to the process of childbirth. For a considerable number of years such methods have been in use in our clinic and for the past five years they have been employed in the pelvic survey of every primigravid woman who has come to the parental clinic for subsequent delivery on our wards. In this group alone we have had an experience totalling over 1200 patients. Furthermore, our experience during this period has also embraced a rather extensive research program which has included studies of the pelvis in adolescents, both male and female, and in adults, also of both sexes. As a result of the clinical application of these procedures we are convinced that pelvic roentgenometry is of pronounced value as a routine procedure in the woman -who is about to have her first child, for by its use pelvic capacity and conformation may be accurately studied and not only major but minor deviations from the normal may be readily identified. Our experience has shown that not only the former but also the latter may be essential factors in the etiology of prolonged labor and the necessity for operative intervention. Among our conclusions the following may be mentioned: 1. The female pelvis is subject to great variations, and a knowledge of the incidence and character of these variations must form the basis for a proper concept of the mechanisms of labor; 2. In order to estimate the capacity of the pelvis for clinical purposes the pelvis must be studied not only as a whole but with particular attention to the pelvic inlet, the pelvic midplane, and the pelvic outlet; 3. In studying these three portions of the pelvis, certain dimensions or diameters are useful gauges, and when these are recorded with certain other descriptive data an adequate description