• A routine screening procedure is needed in the pelvimetric examination of primigravida women in order to discover all cases that deserve closer diagnostic study. The bony pelvis in the pregnant woman is not a rigid, unyielding structure, and complicated x-ray techniques of high accuracy are not essential as part of the routine examination. They should be reserved for cases in which the initial screening leaves doubt as to the functional capacity of the pelvis. The procedure here outlined consists of certain manual techniques plus a single x-ray film obtained according to the Thoms-Wilson technique. This makes it possible to separate pelves into two groups; namely, those that can be relied upon to permit passage of a normal fetus and those that should have further x-ray study before the pelvic survey can be considered complete.
Thoms H, Billings WC. TECHNIQUE FOR ROUTINE PELVIMETRY WITH USE OF A SINGLE X-RAY FILM. JAMA. 1956;160(6):448-451. doi:10.1001/jama.1956.02960410024005