Back to the News 1998 page.New Scientist, 1 August 1998
PENIS ENVY may be a thing of the past. The clitoris, it turns out, is no "little hill" as its derivation from the Greek kleitoris implies. Instead, it extends deep into the body, with a total size at least twice as large as most anatomy texts show, and tens of times larger than the average person realises, according to new studies by Helen O'Connell, a urology surgeon at the Royal Melbourne Hospital in Melbourne.
The clitoris earned its Lilliputian reputation, in part, because much of its elaborate 3D structure is on the inside, hidden by fat and bone--an anatomical smoke screen that has helped fool lay people and experts alike. "There is a lot of erectile tissue down there that is not drawn in any anatomy textbooks, save perhaps a couple of really old dissections in the French and German literature." says O'Connell. "Just because you can't see the rest does not mean it is not there."
Nor does it mean it is not important. O'Connell's detailed descriptions of female sexual anatomy could help prevent women who have pelvic operations from ending up with impaired sexual function.
"The dissections are wonderful," says Cindy Amundsen, a gynaecologist at the University of Houston in Texas. "The erectile tissue is closer to the urethra and encompasses a far larger area of the anterior vaginal wall than most people thought".
O'Connell first realised just how little was known about female sexual anatomy when she was studying for her surgical exams in the late 1980s. Even nowadays, she says, textbooks routinely recycle decades-old, inaccurate illustrations of female sex organs, or omit diagrams altogether. The written accounts can also lack a certain something. One text describes female genitalia as the same as the guys' only turned inside out; another, as the "poor homologue" of the male.
And none of them--not even the anatomists' bible, Gray's Anatomy--describe in detail the nerves and blood vessels that go to the clitoris. "For a surgeon," says O'Connell, "that's unacceptable."
The study of men's sexual anatomy has fared slightly better. Back in the 1970s, modern micro-dissection techniques were brought to bear on the nerves and blood vessels that supply the penis. The information gleaned helped spawn "nerve sparing" surgery that reduces the risk of impotence following operations for diseases like prostate or bladder cancer.
Helped by John Hutson, an expert on paediatric genital reconstruction at the University of Melbourne, O'Connell hoped to do the same for women's sexual anatomy and surgery. But as she started to map out the nerves, she realised it wasn't just the fine detail that was missing from the textbook picture of the clitoris. "I thought, Damn! I'm not sure the gross anatomy is correct, either," she says.
Since then O'Connell and her assistant Robert Plenter have dissected the bodies of 10 adult women, relying heavily on photography to capture the 3D structure of the clitoris. She has described in detail the dorsal nerves (much bigger than in the anatomy books) that are thought to carry the sensory information on the first step of its journey to the brain, as well as the cavernosal nerves that probably control the smooth muscles of the clitoris, and the size of its blood vessels, enabling it to swell during sex. She has also concluded that the clitoris as described in most textbooks is a mere shadow of its real self.
According to O'Connell's dissections, the external tip of the clitoris, or glans, connects on the inside to a pyramid-shaped mass of erectile tissue, far larger than previously described. The "body" of the clitoris, which connects to the glans, is about as big as the first joint of your thumb. It has two arms up to 9 centimetres long that flare backwards into the body, lying just a few millimetres from the ends of the muscles that run up the inside of the thigh. Also extending from the body of the clitoris, and filling the space between its arm, are two bulbs, one on each side of the vaginal cavity.
The bulbs do, in fact, make an appearance in at least some textbooks, but few recognise them as part of the clitoris. Indeed, they are usually referred to as the "bulbs of the vestibule"--the vestibule being the vagina. To make their origins clearer, O'Connell wants to rename them the "bulbs of the clitoris". The penis also has bulbs of erectile tissue at its root that extend into the body cavity, but "the bulbs are more prominent in females", she says.
Gray's Anatomy and other texts also claim that the clitoris, unlike the penis, is entirely separate from the urethra, the tube that connects the bladder to the outside. O'Connell disagrees. According to her dissections, the clitoris surrounds the urethra on three sides, while the fourth is embedded in the front wall of the vagina.
That layout makes perfect sense if you think about what the clitoris has to do. Freud described it as a tool for arousing the rest of the female much as "pine shavings can be kindled in order to get a log of harder wood on fire". But the clitoris also helps squeeze the urethra shut during intercourse, perhaps stopping bacteria making their way up to the bladder and causing an infection. The engorged bulbs of the clitoris may also help hold the walls of the vagina rigid, aiding penetration.
Understanding the clitoris's design, could also help protect women's ability to have good sex. According to O'Connell's descriptions, the cavernosal nerves travel alongside the walls of the uterus, vagina, bladder and urethra. And although practically nothing is known about how operations for, say, incontinence or bladder cancer or hysterectomies affect sexual function, the positions of the nerves suggest that it could be at risk. "Lots of operations involve dissections around the urethra. That could affect patients' sexual function," says Amundsen. Just as doctors routinely ask men who have had prostate surgery about their erections, they should ask female patients who have had comparable operations about any changes in their sexual function, she says.
Now the nerves' pathways are known, it should also be possible to modify at least some operations to reduce the risk of sexual dysfunction. "There have been tons of studies about how to prevent impotence after radical prostectomy," says John DeLancey, an expert on gynaecological anatomy at the University of Michigan in Ann Arbor. Anatomically speaking, a radical hysterectomy for cancer of the cervix is similar to a radical prostectomy. "Given this beautifully detailed knowledge of the interrelationship between the female urethra and sexual organs," it should be possible to develop similar nerve-sparing operations for women, he says.
So why have anatomists routinely got the clitoris wrong? Part of the problem may be a Victorian prudishness about examining women's sexual organs in detail. Then there's the fact that most of the clitoris is hidden inside, shielded by lots of fat and the arch of the pubic bone. Another obstacle to accuracy is that anatomical studies are usually done on the bodies of women in their 80s and 90s. Just as muscle and bone wither with age, so does the mass of erectile tissue in the clitoris. In men, shrinking erectile tissue is less of a problem, at least for the anatomist. More men die in accidents, so young bodies routinely find their way to the dissection table. And as the erectile tissue of the penis is mainly on the outside in one compact piece, it's easier to spot .
O'Connell had two cadavers of women under forty. The older bodies had much smaller clitorises (although still far larger than in the textbooks), but once O'Connell had identified the erectile tissue in the younger women it was easy to find in the older ones. "We lucked out," she says, "one of our cadavers was 36 years old. She looked like an Amazon."
O'Connell is now studying the cellular structure of the clitoris, urethra and vagina. Amundsen, meanwhile, suggests another topic for research: "We have Viagra. We know anatomically what's going on [in the clitoris]. We need some studies on erectile dysfunction in women."
---Susan Williamson is assistant editor at Today's Life Science in Sydney, Australia.
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