Final answer:
The types of dilators used to open the cervix - Pratt, Hank, and Hegar Dilators - are medical tools for cervical dilation. The Simpson Dilator is not a recognized type of cervical dilator.
Step-by-step explanation:
The types of dilators used to dilate or open the cervix include Pratt Dilator, Hank Dilator, and Hegar Dilator. The Simpson Dilator, however, is not recognized as a type of cervical dilator used for this purpose. Instead, when discussing labor and delivery, dilation refers to the thinning and opening of the cervix which precedes childbirth. Cervical dilators are tools used in medical settings to facilitate cervical dilation.
The Pratt, Hank, and Hegar dilators are specially designed to gradually and gently enlarge the cervical canal during medical procedures or before labor inducement. The Simpson Dilator is mistakenly included and does not belong to the category of cervical dilation tools.