Smallest pelvic diameter is: (A) True conjugate, (B) Interspinous diameter, (C) Inteuberous diameter, (D) Posterior sagittal diameter
Answer is B. The interspinous diameter is 10 cm or slightly greater, is usually the smallest pelvic diameter, and, in cases of obstructed labor, is paicularly impoant.(Ref: William's Obstetrics; 25th edition)