which anatomical structure refers to the Shinayim (teeth ) area that the gemara mentions; would this be the cervix area?
in connection with previous dapping which alluded that uterine blood expelled through a tube (shefoferet) and bypassing the prosdor seems to be tahor and therefore the cervix area seems to be the structure where the blood turns tamei
how is this reconciled with the man de'amar that says that mekor mekomo tamei?
thank you in advance
Sorry for taking so long to get back to you.
Regarding your questions: According to most Mefarshim - including Rashi and Tosafos - the Shinayim is the external orifice of the cervix (the one that devides the Prozdor from the cervix), but according to the Chasam Sofer (Teshuvos, Yoreh Deiah, number 167) it is the internal orifice (the one that devides the cervix from the uterus). One difference in Halachah between the two opinions will be the case of "haRo'eh Dam b'Shefoferes" (Nidah, 21b). According to the Chasam Sofer the Shefoferes would have to be inserted all the way into the uterus proper or else it will be considered Dam Nidah.
Rav Shlomo Zalman Auerbach argues with the Chasam Sofer and says that according to the Chasam Sofer marital relations could potentially render the woman a Nidah because of the Klal "Ein Pesichas haKever b'Lo Dam" (see Minchas Shlomo, Volume II, chapter 70, section 4). The Chasam Sofer bases his opinion on the Rambam but Rav Auerbach claims that the Rambam used different terminology then we use today. In his day what we refer to as the Prozodor (or Nartik) was called the Tzavar haRechem (which for us means the cervix).
Regarding the opinion "Mekor Mekomo Tamei": it seems that Dam b'Shefoferes only saves the woman from becoming a Nidah (Tumas Shivah) but the Dam is still an Av ha'Tumah and is Metamei for one day (Tumas Erev). The proof of this is that the blood that comes along with a baby being born via c-section (Yotzei Dofen) is Tamei despite not going through the cervix at all.
Gemar Chasima Tovah,
This is not a Psak Halachah