The Pelvic Survey *

From the standpoint of child-bearing, the interest of obstetricians in the female bony pelvis is not limited to pelvic dimension, for morphology of the pelvis is also of importance. Of interest too are those factors which may influence the development of the pelvis during childhood and the pulberal period. When we consider methods which will show pelvic capacity and pelvic morphology in the living individual, we find that only roentgen technics are able to give us knowledge of the upper bony birth canal, and that the lower portal or outlet can be satisfactorily evaluated by palpatory methods. For clinical purposes a satisfactory survey, therefore, should combine both measures and it is the purpose of this communication to describe the technics now in use in this clinic. In considering the former, it is obvious, for the sake of practical application, that roentgen methods should aim at simplicity in interpretation and at a minimum of expense. Both of these objectives are obtained in the use of two roentgenograms, one obtained by projection from above downward with the target centered on a line at right angles to the plane of the pelvic inlet, and the other projected laterally. In the inlet view the shape and dimensions of the pelvic inlet and the midplane can be measured, and certain outlet characteristics can be made apparent, while in the lateral view the lateral aspect of the pelvis may be studied and certain anteroposterior dimensions obtained. For the inlet view we are using a modification of the grid technic, which was originally devised in this clinic and later modified.8 In this maneuver a scale of "corrected" centimeters appears at the edge of the film, whereby correction of distortion due to the spread of the x-rays can be made for the pelvic inlet and other important levels. The entire bony pelvic canal is obstetrically important. This is particularly true in those instances where the upper pelvis (inlet) may show adequate pelvic room and the lower pelvis (midplane) show a restricted capacity. When such midplane contraction occurs the fetal head usually shows good engagement but labor becomes