Information obtained by lateral plate X-ray pelvimentry are all except :
X-ray pelvimetry is of limited value in the diagnosis of pelvic contraction or cephalopelvic dispropoion.X-ray pelvimetry is a poor predictor of pelvic adequacy and success of vaginal delivery. However, X-ray pelvimetry is useful in cases with fractured pelvis and for the impoant diameters which are inaccessible to clinical examination (see below). Techniques: For complete evaluation of the pelvis, three views are taken -- anteroposterior, lateral and outlet. But commonly, X-ray pelvimetry is restricted to only the erect lateral view (the femoral head and acetabular margins must be superimposed) which gives most of the useful information. Anteroposterior view can give the accurate measurement of the transverse diameter of the inlet and bispinous diameter. Limitations of X-ray pelvimetry: The following are the prognostic significances of the successful outcome of labor: (1) Size and shape of the pelvis; (2) Presentation and position of the head; (3) Size of the head; (4) Moulding of the head; (5) Give way of the pelvis; and (6) Force of uterine contractions. Out of these many unknown factors, X-ray pelvimetry can only identify one factor, i.e. size and shape of the pelvis. Thus, it can only supplement the clinical assessment of pelvis but cannot replace the clinical examination. Otherwise it is true that satisfactory progress of labor is the best indicator of pelvic adequacy. Hazards of X-ray pelvimetry includes radiation exposure to the mother and the fetus. With conventional X-ray pelvimetry radiation exposure to the gonads is about 885 millirad. So it is restricted to selected cases only. Diagnostic range of radiation exposure (less than 5 rads) is not associated with any significant congenital malformation either in human or in animal. Reference: D C Dutta Textbook of Obstetrics 7th edition page 351
Sacral curve
True conjugate
Bispinous diameter
Inclination of the pelvis
General obstetrics