Denominator refers to:
Denominator : It is an arbitrary bony fixed point on the presenting pa which comes in relation with the various quadrants of maternal pelvis. Denominators in different presentations : Occiput in veex Mentum in chin Frontal eminence in brow Sacrum I'm breech Acromion in shoulder. Ref: Datta Obs 9e pg 70.
Pa of the presentation which lies over the Internal os
Relation of different pas of fetus to one another
Bony fixed point of reference on presenting pa
Pa of fetus lying in the lower segment of uterus
General obstetrics