This method of pelvimetry is based on one described to me by Dr. Tennant of Birmingham in 1938. Four diameters of the female pelvis are obtained: 1. Transverse diameter of the pelvic inlet. 2. Obstetric conjugate (either the true conjugate, Caldwell-Molloy or “available conjugate”). 3. Mid pelvis (symphysis to middle of third sacral segment). 4. Outlet diameter (to terminal point of the last fixed sacral segment).