A cervical cap for covering a portion of the cervix uteri in order to prevent migration of sperm from the vagina into the cervical canal to thereby prevent conception. The cervical cap has an open end portion, a dome-shaped portion, preferably sealed, disposed opposite the open end portion, and a ridged...http://www.google.es/patents/US4961436?utm_source=gb-gplus-sharePatente US4961436 - Contraceptive cervical cap
