Fig. 2.

Solid model corresponding to the subject with cervical insufficiency

A subject with cervical insufficiency was studied prior to the placement of a physical-examination indicated cerclage. The ultrasound images show protrusion of the amniotic sac to the level of the external os (white arrows, top). A solid model of this anatomy was constructed, which shows the marked cervical deformation associated with cervical insufficiency (bottom). The solid models accurately captured the anatomy of interest. Of note, this subject delivered at 26 weeks gestation.