Anatomy of the G-spot

The G-spot is surrounded by myth, mystery and an enormous amount of debate and controversy. There is much opinion on both sides, usually with little supporting evidence offered. Here we take you through the facts and the studies.

The G-spot is associated with an organ called the Female Prostate, which is similar to the male prostate and looks like this:

In 2001 the Female Prostate was introduced into the Histology Terminology, a document published by a international group of top Anatomists, FICAT, based on work by Dr. Milan Zaviacic. FICAT define the microscopic anatomy of the human body in its entirety. What FICAT include in their definition is not open for debate by non-anatomists. Thus, the location and existence of the Female Prostate is not in question. It exists, it's real, and every single woman in the world has one (barring surgical removal). 

By contrast, the term 'G-spot' has no official, universally accepted medical or anatomical definition. However, most (but not all) writers would define it as a bumpy, ridged area, found about 3-5cm inside the vagina, on the front wall (the wall closest to the clitoris), and about 2-4cm long. It's shown as the white spot in the diagram below:

As you can see, the G-spot is right beside the female prostate. When you stroke the G-spot, you indirectly stroke the female prostate.

Deborah Sundahl, author of Female Ejaculation and the G-spot, does not follow this definition. She considers the G-spot to actually be one and the same organ as the female prostate, in it's entirety, not simply the zone closest to the female prostate.

And since the term 'G-spot' has no medical definition, it is open to interpretation. Contrary to Sundahl, most writers seem to prefer the definition given previously, denoting the G-spot as just that - an accessible spot/area/zone of skin inside the vagina, which just happens to be closest to the female prostate. This leaves the female prostate itself, according to Zaviacic, as a

functional genitourinary organ with a specific structure, function and pathology.

The Link to Female Ejaculation

The area around the G-spot swells up (engorges with blood) during sexual excitation and, in some women, produces pleasure and orgasm. The female prostate surrounds the urethra, through which Female Ejaculation exits the body. Female ejaculation occurs most often during G-spot massage.

Zaviacic continues:

The female prostate has two functions: exocrine (production of prostatic fluid - the female ejaculate) and neuroendocrine (production of hormones).

So, the G-spot is the closest accessible point to the female prostate, which plays a crucial role in G-spot orgasm and female ejaculation.

Part of the disbelief surrounding the G-spot stems from some Anatomists' and Gynaecologists' statements over the years. Gynaecologist Terence Hines claimed the G-spot a myth in 2001. He wrote that if the G-spot were to exist, then corresponding sexually sensitive nerve endings must be found. He cites a team of anatomists who analysed 24 specimens of vaginal tissue. Hines believed the epithelium, a layer of skin contained within the epidermis (the outer skin) should contain the nerve endings in question, known as Meissner's Corpuscles.


Touch Sensitive vs Pressure Sensitive

In the diagram below, a normal layer of skin (not a g-spot specimen), Meissner's Corpuscles are shown as the brown tadpole/sperm like shape on the upper right hand side in the diagram below, labelled 'sensory nerve ending for touch'. The anatomists found no such nerve endings in their vaginal samples.

However, what Hines failed to account for was the difference between touch sensitive and pressure sensitive nerve endings. He writes:

The anterior vaginal wall showed more innervation than the posterior wall, but this was subepithelial, and there was “no evidence for intra-epithelial innervation of this part of the vagina.” Such innervation would be expected if a sensitive G-spot existed in the area.

So, many nerve endings were found, but they were 'subepithelial' (below the epithelium), in the layer labelled 'Dermis' in the diagram above. Known as Pacinian Corpuscles, and shown as the green tadpole / sperm like shape above, they are pressure sensitive nerve endings.

Hines believed that if the G-spot were to be real, it would have to contain the touch sensitive kind, close to the surface, in the epidermis.

Hines clearly did not consider Pacinian Corpuscles, which also happen to be the same, sexually responsive, pressure sensitive nerve endings found in the glans (head) of the clitoris and penis. These nerve endings are critical in the stimulation that results in sexual pleasure and orgasm.
It may the case that the surface of the skin at the G-spot is similar to the glans penis and glans clitoris, in that all three are both pressure sensitive, but not touch sensitive. The foreskin of the penis and clitoris, and the labia, on the other hand, are all touch sensitive, but not pressure sensitive.

Believe it or not, the penile glans has been found to be insensitive to light touch, heat, cold, and even to pinpricks.
So the glans contains only pressure sensitive nerve endings. Since penile stimulation is far more effective on the glans (and indeed on the clitoris as indicated by pulling the clitoral foreskin back and stimulating the glans while moist) this would indicate that Pacinian corpuscles are far more critical in orgasm than touch sensitive nerve endings.

So when Hines writes "Such innervation would be expected if a sensitive G-spot existed in the area" he refers to near-surface touch sensitive nerve endings and clearly omits the possibility of lower lying, pressure sensitive Pacinian corpuscles.

The outer third of the vagina, and indeed the labia and outer vulva are rich in touch sensitive nerve endings, and it is clearly this type that Hines was considering. A quick flick through any 'how to' G-spot book or article will of course tell you that the G-spot needs heavy, firm pressure. A light, stroking touch does nothing.

Infamous 1950s sex researcher Alfred Kinsey and Masters and Johnson in the 1960s also made this classic mistake. They used a cotton bud (Q-tip) to lightly stroke the G-spot, got no sexual response from their subjects, and concluded the G-spot to be a myth.


The G-spot: the Possibilities

So, the real question is not 'Does the G-spot exist?' but this: 'What percentage of women have a responsive g-spot?' Here are the possibilities:

#1. The G-spot is a total myth, and women who say they're having G-spot orgasms are actually having clitoral orgasms.
#2. Some women can naturally have G-spot orgasms, some can't, and nothing can be done to change that.
#3. Some women can naturally have G-spot orgasms, some can't, and some can, given the right training.
#4. All women can have G-spot orgasms, all that's required is the correct technique.

As there is a real lack of study in this area, and since there are so few studies on the G-spot, the answer at this stage truly is unknown. Most writers would discount possibility #1. Disproving #1 would simply involve proving a G-spot orgasm, with no clitoral contact, for a single woman. Work by John D. Perry, co-author of the 1982 book The G Spot and Other Recent Discoveries About Human Sexuality in the which the term 'G-spot' is coined, shows that clitoral and G-spot orgasms invoke different muscles and nerve pathways:

Perry writes:

In Panel B, we see a traditional "clitoral" orgasm brought on by clitoral stimulation; there is little uterine activity during clitoral stimulation. During G Spot stimulation, there is much PC activity, and more uterine activity

He writes further that:

it is especially interesting that in the third "blended" orgasm, the uterine muscles peaked fully 1.3 seconds BEFORE the PC muscle did, which substantially proves that the two orgasmic contractions are mediated by different nerve fibers and reflexes.

So it would seem that possibility #1 above is disproved; it cannot be said that the G-spot is a total myth, and must be responsive in at least some women. Whether the female prostate is involved in the orgasm can be questioned; but the point of stimulation, the G-spot, seems certain.
However, any of possibilities #2, #3 and #4 above may turn out to be true.

One of the theories proposed as to why more women don't have G-spot orgasms is as follows:
When young women first begin to have sex, they may get the initial feelings of female ejaculation as a result of stimulation on their G-spot. However, the general lack of knowledge of female ejaculation means that a woman will generally believe the feeling to be one of urination (it's not; see the female ejaculation page).
It's believed that the most likely way to achieve G-spot orgasm is for the woman to relax her PC muscle.
If a woman gets the 'pee feeling' during sex, she will likely tense her PC muscle in order to prevent what she believes is urination. However tensing the PC muscle will put pressure on the female prostate and prevent both G-spot orgasm and female ejaculation from building up.

Further Discussion
Thoughts, comments, questions on the G-spot or this article? You can join the discussion in the G-spot forum.