A speculum is a metal instrument consisting of two rounded blades on a hinge. It is placed inside the vaginal canal and the blades are then opened, allowing the doctor to see the mouth of the cervix (the opening of the uterus).
A speculum examination usually causes no bleeding, and the doctor can often confirm that he sees no blood exiting the cervix. If, however, he does see blood exiting the cervix, the woman becomes niddah. If there was no blood exiting the cervix and a small amount of blood is found on the speculum, it may be attributed to abrasion of the walls of the vagina – especially if the woman's vaginal lining is sensitive or if the examination was performed without lubrication. (Gynecological examinations are often done with lubricating jelly; however, for a Pap smear only water is used, because the jelly can interfere with test results.)
Because the speculum does not enter the cervical canal, most authorities rule that it presents no problem of niddah due to opening of the uterus.
Users of Internet filtering services: This site discusses sensitive subjects that some services filter without visual indication. A page that appears 100% complete might actually be missing critical Jewish-law or medical information. To ensure that you view the pages accurately, ask the filtering service to whitelist all pages under yoatzot.org.