<prompt> Longest diameter of fetal skull is?Occipito frontalSubmentobregmaticSuboccipito frontalMento vertical  <response>: Ans. d Mento verticalRef : D.C. Dutta 8th ed. 94-97DIAMETERS OF SKULL The antero-posterior diameters of the head which may engage are:DiametersMeasurment In CmPresentationSuboccipito-bregmatic9.5 cmVertexSuboccipito-frontal10 cmVertexOccipito - frontal11.5 cmVertexMento-vertical: extend from mid-point of chin to the highest point on the saggital suture14 cmBrowSubmento-vertical11.5 cmFaceSubmento-bregmatic9.5 cmFace The transverse diameters which are concerned in the mechanism of labor are Biparietal diameter - 9.5 cm: extends between two parietal eminences. Super-subparietal - 8.5 cm Bitemporal diameter: 8 cm Bimastoid diameter - 7.5 cm 