suboccipitobregmatic diameter

sub·oc·cip·i·to·breg·mat·ic di·am·e·ter

the diameter of the fetal head from the lowest posterior point of the occipital bone to the center of the anterior fontanelle; this is typically the smallest diameter and is the one that presents, optimally, in labor.

sub·oc·cip·i·to·breg·mat·ic di·am·e·ter

(sŭb'ok-sip'i-tō-breg-mat'ik dī-am'ĕ-tĕr)
The diameter of the fetal head from the lowest posterior point of the occipital bone to the center of the anterior fontanelle.
References in periodicals archive ?
Using measurements of fetal head diameters (FIGURE 3), it is easy to see why a vertex presentation in an occiput anterior position (presenting diameter = suboccipitobregmatic diameter = 9.5 cm) will deliver more easily than a baby in a deflexed occiput posterior position (presenting diameter = occipitofrontal diameter [greater than or equal to] 11.5 cm).