<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">I did find one further bit of information, copied below, but am still looking for something more conclusive, if such an approach exists.<DIV><BR class="khtml-block-placeholder"></DIV><DIV>The following is from the Daf Yomi Advancement Forum (<A href="http://www.dafyomi.co.il/nidah/insites/ni-dt-17.htm">http://www.dafyomi.co.il/nidah/insites/ni-dt-17.htm</A>):</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Times">(a) </FONT><FONT class="Apple-style-span" face="Times"><B>RASHI</B></FONT><FONT class="Apple-style-span" face="Times"> and </FONT><FONT class="Apple-style-span" face="Times"><B>TOSFOS</B></FONT><FONT class="Apple-style-span" face="Times"> explain that the Aliyah is located on the roof of the Prozdor (that is, it is only to one side of the cervical canal). Occasionally, blood comes into the Prozdor from the Aliyah, but its blood is not like the blood of Nidah. There are five different colors of Dam Nidah, and there is only one color of blood that flows from the Aliyah (</FONT><FONT class="Apple-style-span" face="Times"><B>TOSFOS</B></FONT><FONT class="Apple-style-span" face="Times"> DH v'Dam). There is an opening from the Aliyah through the roof of the Prozdor.</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Times">The </FONT><FONT class="Apple-style-span" face="Times"><B>CHASAM SOFER</B></FONT><FONT class="Apple-style-span" face="Times"> (YD 188) points out that it is very difficult to resolve this description with the actual anatomy. There is no attic of any sort next to the womb! Some answer that according to the explanation of Rashi and Tosfos, the Aliyah is not part of a normal woman's anatomy, but rather it is a hole that forms in some women due to illness, and through this hole blood enters from the bladder (or other organs) into the Prozdor.</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Times">(b) The </FONT><FONT class="Apple-style-span" face="Times"><B>RAMBAM</B></FONT><FONT class="Apple-style-span" face="Times"> (Perush ha'Mishnayos, and Hilchos Isurei Bi'ah 5:3) explains that the Aliyah refers to the uterine (fallopian) tubes that are attached to the top of the uterus from either side, which connect the ovaries to the uterus. This explanation matches the actual anatomical structure much more accurately, as the Chasam Sofer points out. The Rambam writes further that it is not common for blood to flow into the uterus from the uterine tubes, but it occasionally happens due to a wound or illness. Such blood is not Dam Nidah. It enters the Prozdor via the Lul, which is an opening between the Prozdor and the uterine tubes.</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Times">(According to the Rambam's explanation as well, it is not clear what, and where, this opening (Lul) is. The only natural opening in the uterine tubes appears at the head of the uterus where the uterine tubes connect to the uterus, but this is far from the Prozdor (the cervical canal, which is at the other end of the uterus)! It seems, therefore, that even according to the Rambam, the Lul is a hole that is formed due to illness.)</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Times">However, the Rambam's explanation is very difficult to understand for the following reasons:</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Times">First, the Gemara says that the blood of the floor of the Prozdor is Metamei more than that of the ceiling of the Prozdor, since the Lul opens into the ceiling of the Prozdor from the Aliyah above it. According to the Rambam, the Aliyah refers to the uterine tubes on *both* sides of the Prozdor, and, therefore, it is open to both of them. Why, then, should there be a difference between the "ceiling" and the "floor" of the Prozdor?</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Times">Second, the Gemara says that blood found from the Lul outward is more likely to be Tahor than blood found from the Lul inward. According to the Rambam, however, who says that the Lul is open to both sides of the Prozdor (since there is an Aliyah on each side), how can the Lul outward be more Tahor than from the Lul inward? *All* of the blood of the woman passes from the Lul (or one of the Lulim) outwards when it exits, whether it comes from the Aliyah or from the uterus! The blood there should be no better than a Safek!</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Times">Perhaps we may answer these questions as follows.</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Times">First, the "Gag" (ceiling) of the Prozdor actually refers to the upper part of the Prozdor itself, beyond the Lul and closer to the uterus. The Rambam maintains that this part of the Prozdor is Metamei more than the floor -- that is, the part of the Prozdor below the Lul -- which is more Tahor. (This is the opposite of the explanation of most Rishonim, who explain that the ceiling is more *Tahor* than the floor.)</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Times">Second, according to the Rambam, the reason why blood found from the Lul and outward is Tahor is because when blood (Dam Nidah) comes from the uterus, it flows out together (or one drop comes out before the rest, but it remains close to the uterus, as Rashi explains on 2b, DH ha'Gas). When only a drop of blood is found outside of the Lul, it can be assumed that it is from the Lul and not from the Dam Nidah of the uterus. (M. Kornfeld)</FONT></DIV><DIV><BR><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV>--</DIV><DIV>Yoav Elan</DIV><DIV><A href="mailto:yoavelan@yahoo.com">yoavelan@yahoo.com</A></DIV><DIV><BR class="khtml-block-placeholder"></DIV><BR class="Apple-interchange-newline"></SPAN></SPAN> </DIV><BR></DIV></BODY></HTML>