Conjugate of the diagonal is 'a' cm, obstetric conjugate will be:
Ans. is d, i.e. (a -2) cmRef. Williams Obs. 24/e, 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
a+1 cm
a+2 cm
a-1 cm
a-2 cm
Fetal Skull and Maternal Pelvis