Vaginal Nerviness and What I would Say Differently If I Made This Movie Now
So, I found an article that prompts me to let you all know I would probably would have said something in the movie a little differently. It's about the amount of nerve endings in the vagina.
In the movie we say that compared to the vulva, the inside of the vagina has lots less nerve endings, which I'll stand behind. However, we also go on to say that there are more nerve ending in the front (towards the hole) than in the back depths of the vag, which we say has almost none. We also go on to say that this lack of nerve ending allows for surgeries to happen in the vagina without anesthesia. I got that from Alfred Kinsey's classic, Sexual Behavior in the Human Female (W.B Saunders Company, Philadelphia, 1953) pages 159-171 and 577-584. He had done tests where different parts of the vulva were gently stroked with a probe and different parts inside the vagina were both stroked and/or given pressure. Whether the 879 women tested could identify that they were being touched or where exactly they were being touched in each area was noted. The results of that study, along with studies from the 40's and 50's he cited (one's in German, I think)  and from histologic data he received from 2 scientists on vaginal innervation , prompted Kinsey to make the claim that the vagina is not particularly nervy except for the area that is basically the opening. He also cited that "From our gynecological consultants, we have abundant data on the limited necessity of using anesthesia in vaginal operations" and cited a related study .
So that's where it came from. I now think it could be wrong to say there are less nerve endings in the furthest inner parts of the vagina. I found an article in The Journal of Sexual Medicine called, "A prospective study examining the anatomic distribution of nerve density in the human vagina." 2006 Nov;3(6):979-87. In my defense, this was at the very end of my heavy research for this movie, but who knows if I would have found it anyway. There are tons of little one-off lady-gasm related studies that are either not conclusive or often just kinda bad that I had no interest in using for the movie and it's hard to keep up with checking them all. This one would have been good though.
Although it's small (only 21 women), it is a physiological investigation - a first of it's kind really. Plus, I don't think its claims are overreaching. Basically, the authors had the women take a standardized questionnaire about their sexual functioning (arousal, orgasm, lubrication, satisfaction, pain, etc.) and then took tissue samples from different areas of their vagina (i.e. cervix, front wall closer to hole, back wall closer to hole, and deeper on both front and back walls.). They also took samples from the different layers of the vaginal tissue in all those places. What they concluded was that the vagina had about the same amount of nerves throughout every place they tested, and that there was no significant difference between the women's amount of nerves; not between women with or without Female Sexual Dysfunction, not between with different scores on orgasm, lubrication, arousal, etc., not between pre and post menopausal. The had all given birth, but there was no difference between those with 3 or more and those with less than 3 births. One possible issue was that all the women had prolapse (where some pelvic orgasm had fallen out of place) and that this condition had been associated in one study with women saying they had less sensation in the vagina. However, the study was done this way because these women were going into surgery anyway, so getting the samples was essentially non-evasive and thus the study could actually get done. The researchers did look to see if there was a correlation between less nerves and the further stages of prolapse, but that wasn't the case either.
As Kinsey pointed out in his research and as this study points out, a study of the amount of nerves in the tissue of the vagina does not also necessarily indicate what may or may not be pleasurable to women inside the vagina. The amount of nerves does not also point to the nerve behavior, and there are plenty of other factors that go along with what physical actions feel pleasurable to someone. However, it is solid useful information for further investigation into female sexual response.
Again, this is a small study, but it seems well done, and it would prompt me not to assert that there is different areas of the vagina that are less nervy than others.
This also brings up something related. I have recently realized that discussing the vagina as not-so-nervy and specifically saying that there are surgeries done in the vagina without anesthesia, is a kind of trigger for people and can immediately turn them off to anything else I have to say. It seems that it conjures up a distaste that some people have for the ideals of some 70's feminists (particularly to Anne Koedt and her article The Myth of the Vaginal Orgasm ) who boldy pointed out that Masters and Johnson's groundbreaking (and still completely relevant) research showed that orgasms are caused by clitoral and not vaginal stimulation. I could be wrong, but I think maybe it simply has something to do with a misunderstanding that these feminists were also saying that the vagina is a pleasureless hole and that enjoying intercourse is basically stupid and un-feminist. I, in no way, think that was what they were saying at all, but I also know that sometimes things trigger bad feelings, and I wish I would have known that before I put the statement about anesthesia and vaginal surgery it into the movie.
I see now that it can easily be taken as a shorthand for me saying that the vagina is useless. I do say clearly that vaginal stimulation has not been shown to cause orgasms, but I never say that vaginal stimulation is never or never should be part of sexual stimulation and arousal. I believed I had made that distinction clear in the movie, but I didn't say it as clear as it could have been said. Plus, although there are surgeries done in the vagina without anesthesia , there are also surgeries done with anesthesia. I think the statement I put in the movie is just a bit too much because instead of backing up the idea that the vagina is less sensitive than the outer vulva and that vaginal stimulation does not cause orgasm, it gives the impression that I don't think there is any sensitivity in the vagina at all and that it could not possibly be important to arousal.
So - I was possibly wrong about different areas of the vagina having different amounts of nerves. Also, if I were to make this movie again, I would be more sensitive about the issue of vaginal sensitivity and be way, way more clear about my notion that the vagina, while not an orgasm causing organ, is surely an arousal causing organ...and thus I would not bring up the whole vaginal surgery - no anesthesia thing.
 Kuntz, A. 1945, Ed. 3. The autonomic nervous system. Philedelphia, Lea & Febiger, 1 pl. + 687p.
 Undeutsch, U. 1950. Die Sexualitat im Jugendalter. Studium General 3:433-454.
 "Dr. F.J. Hector (Bristol, England) and Dr. K.E. Kranz (University of Vermont) have furnished us with histologic data on this point."
 Doberlein, A. and Kronig, B. 1907. Operative Gynakologie. Leipzig, Georg Thieme, xvi +721p.
Clifton PA, et al. Journal of Family Practice. "Ineffectiveness of topical benzocaine spray during colposcopy." 1998 Mar;46(3):242-6.
Sammarco MJ Hartenbach EM, Hunter VJ. The Journal of Reproductive Medicine. "Local anesthesia for cryosurgery on the cervix." 1993 Mar;38(3):170-2.