<prompt> Conjugate of the diagonal is a cm, obstetric conjugate will be:a1 cma2 cma-1 cma-2 cm  <response>: Ans. is d, i.e. a -2 cmRef. Williams Obs. 24e, p 32Obstetric conjugate cannot be measured clinically but can be diagnosed by substracting 1.5-2 cm from diagonal conjugate. Hence if diagonal conjugate is a cm obstetric conjugate will be a -2 cmObstetric conjugate normally measures 10 cm or more Q.The pelvic inlet is considered to be contracted, if obstetric conjugate is less than 10 cm. Q 