Notes on Genital Dimensions

By Anne A. Lawrence, M.D., Ph.D.


Men commonly boast about and exaggerate their genital dimensions. Some male-to-female transsexuals engage in this kind of behavior after undergoing SRS: "My surgeon gave me six inches of vaginal depth." "Oh yeah? Well, my surgeon gave me seven inches." Sometimes one hears a variation on the same general theme: "My boyfriend is so big that I needed eight inches to accommodate him." And so forth.

Listening to comments like these, some transsexual women may develop unrealistic beliefs and expectations concerning vaginal depth following vaginoplasty. Here are a few observations that transsexual women might want to keep in mind:

Vaginal depth in natal females typically ranges from 7 to 14 cm, or about 3 to 5-1/2 inches.

Some of the best data concerning vaginal depth in natal females come from Masters and Johnson's Human Sexual Response (1966). The diagrams below are taken from pages 73 and 74 of that book. Typical vaginal depth in Masters and Johnson's participants ranged from 7-8 cm in an unstimulated state, to 11-12 cm during sexual arousal with a speculum in place. Nulliparous in the figures below refers to women who have not given birth.

Thirty years later, Pendergrass, Reeves, Belovicz, Molter, and White (1996) found slightly higher numbers. They measured vaginal depth in 39 women, only one third of whom were nulliparous. They found an average vaginal depth of 11.5 cm (4-1/2 inches), with a range of 6.8 cm to 14.8 cm (2-3/4 to 6 inches).


Erect penile length in males averages 13 to 15 cm, or about 5 to 6 inches.

Wessels, Lue, and McAninch (1996) reported an average erect length of 12.9 cm in a group of 80 normal men. Harding and Golombok (2002) reported an average erect length of 15.3 cm in a group of 312 gay men. In the latter study, measurements were taken by the men’s partners, which may account for the somewhat higher figure reported.


Consequently, penile length probably exceeds vaginal depth in many, perhaps most, heterosexual couples.

Transsexual women who find that their vaginas are shorter than the penises of their male partners should realize that many natal females share the same experience. Most of these natal women are not running to plastic surgeons asking to have their vaginas deepened.


The depth of the neovagina is usually limited by the length of the rectovesicle septum, typically 10 to 12 cm, or about 4 to 5 inches. This is well within the normal range for natal females.

The neovagina is created in the space between the rectum and the bladder. This space is called the rectovesicle septum or Denonvillier's fascia. The figure below shows the relevant pelvic anatomy in cross section.

Dissection of the vaginal cavity can continue along the rectovaginal septum until the surgeon reaches the peritoneal reflection, sometimes called the Douglas pouch. Typically, the peritoneal reflection is reached at a depth of 10 to 12 cm (4 to 5 inches), according to recent anatomic studies by Giraldo, Mora, Solano, Gonzáles, and Smith-Fernández (2002). Dissection can only be carried farther if there is a deliberate intention to enter the peritoneal cavity, as might be the case during a colon segment vaginoplasty.

I wrote to Dr. Giraldo about this issue, and he replied to me as follows:

"We performed [measurements on] sagital preparations of the pelvis in 2 out of 14 male human cadavers. Measurements of the rectovesical space were 12.5 cm and 10.5 cm. Additionally, I have carefully measured the length of the cavity in my MTF SRS cases (38 in the last 3.5 years). The mean length of this cavity from the perineal skin to the Douglas pouch, without vaginal speculum pressure, was 10 to 12 cm. Both in anatomic and clinical dissections, the surgeon finds a true anatomical stop at the Douglas [pouch]. Only if this anatomic limit is surgically modified would it be possible to obtain larger rectovesical cavities and larger neovaginas (i.e., [when] using intestinal segments). I wholeheartedly agree with you that cutaneous neovaginas more than 12 cm long (i.e., 15 cm) are really difficult to find if a correct and scientific evaluation is carried out. The Amsterdam Gender Team, Hage & Karim, has reported similar mean lengths, 10-12 cm, in many articles."
(F. Giraldo, personal communication, January 30, 2003)

Measurement of vaginal depth during the immediate postoperative period may explain some reports of vaginal depth greater than 15 cm, or about 6 inches.

Tissue swelling occurs at the vaginal opening immediately after surgery, is maximal on postoperative day two or three, and typically persists for several weeks. Consequently, vaginal depth measured in the immediate postoperative period is likely to overestimate final vaginal depth by an unknown amount.

As Dr. Giraldo notes, honest vaginal depths of 15 cm or more are rarely encountered except with colon segment procedures. Blanchard, Legault, and Lindsay (1987) found a maximum vaginal depth of 13 cm in their group of 22 patients, while McEwan, Ceber, and Daws (1986) reported that only 3 of their 33 patients (9%) had measured vaginal depths of 15 cm or greater.


Limited vaginal depth following SRS can often be accommodated during coitus, perhaps by adjustment of the partners’ positions.

McEwan, Ceber, and Daws (1986) reported that 8 of their 9 patients with vaginas less than 10 cm in length were engaging in vaginal intercourse. Blanchard, Legault, and Lindsay (1987) found that 11 of 19 patients reported a vaginal depth that was adequate for all or virtually all partners, 3 of 19 reported a depth that was inadequate for some partners, and only 5 of 19 reported a depth that was inadequate for most or all partners. Median depth in their series was only 8.5 cm. They speculated that, "It is possible that transsexuals accomplish coitus, despite short vaginas, by assuming positions that limit the depth of their partners' thrusting" (p. 265).

References:

Blanchard, R., Legault, S., & Lindsay, W. R. N. (1987) Vaginoplasty outcomes in male-to-female transsexuals. Journal of Sex and Marital Therapy, 13, 265–275.

Giraldo, F., Mora, M. J., Solano, A., Gonzáles, C., & Smith-Fernández, V. (2002). Male perineogenital anatomy and clinical applications in genital reconstructions and male-to-female sex reassignment surgery. Plastic and Reconstructive Surgery, 109, 1301-1310.

Harding, R., & Golombok, S. E. (2002) Test-retest reliability of the measurement of penile dimensions in a sample of gay men. Archives of Sexual Behavior, 31, 351-357.

Masters, W. H., & Johnson, V. E. (1966). Human Sexual Response. Boston: Little, Brown.

McEwan, L., Ceber, S., & Daws, J. (1986). Male-to-female surgical genital reassignment. In W. A. W. Walters & M. W. Ross (Eds.) Transsexualism and Sex Reassignment (pp. 103-112). Melbourne: Oxford University Press.

Pendergrass, P. B., Reeves, C. A., Belovicz, M. W., Molter, D. J., & White, J. H. (1996). The shape and dimensions of the human vagina as seen in three-dimensional vinyl polysiloxane casts. Gynecologic and Obstetric Investigation, 42, 178-182.

Wessells, H., Lue, T. F., & McAninch, J. W. (1996) Penile length in the flaccid and erect states: guidelines for penile augmentation. Journal of Urology, 156, 995-997.



© 2011 by Anne A. Lawrence, M.D., Ph.D. All rights reserved.