Figure 1From: A simplified cervix model in response to induction balloon in pre-labourRelevant anatomy and balloon dilator applied to the cervix. A balloon catheter is placed in the space between the amniotic sac and the interior os of the cervix to induce labour. From left to right, as the cervix softens it effaces (thins) and dilates (opens), permitting the balloon to descend and eventually exit.Back to article page