Question: Hello, I am an 18 year old girl and I'm worried about the depth of my vagina. I have read through the Q&A on your website about vaginal depth increasing after becoming sexually aroused. I don't believe this happens for me. When I masturbate and feel fully aroused, and am self lubricating, I can still only insert an object about 3 inches into my vagina before it hits my cervix. After that even applying light pressure to the cervix and continuing to masturbate doesn't seem to have any effect in lengthening my vagina. Even after I have reached orgasm it still does not appear to be lengthened! I am worried because I want to experience intercourse with my boyfriend, but his penis is much larger than the average 6 inches, and I know it will be a huge disappointment if it can only go in 3 inches deep! It is a huge disappointment to me as well. I want to be penetrated at least deeper than 3 inches. I don't know what to do about this, could there be some kind of hormonal problem? Or am I cursed with a shallow vagina forever?
Answer: You are not the first to ask about this subject, or to be concerned by how close their cervix is to their vaginal orifice, i.e. the shortness of their vagina. Many women are surprised they can touch their cervix with their fingers, given their fingers are less than six inches in length, but a penis is six inches in length on average. Based on the messages we receive from society we may expect the vagina to be practically bottomless.
In a medical article about Magnetic Resonance Imaging (MRI) conducted while couples were engaged in sexual intercourse it states:
"In complete penetration the penis filled up the anterior [front] fornix* or the posterior [back] fornix. During intromission [penetration] the pubic bones of the men and women did not approach each other closely: the female pubic bone stayed about 4 cm [1 1/2 inches] cranial [above, towards head] to that of the male. The uterus raised by 2.4 cm [1 inch].
"[During penetration,] In the pre-orgasmic phase the anterior vaginal wall lengthened by 1 cm [slightly less than a half inch] and the uterus rose within the pelvis.
"During sexual arousal without coitus [penetration], the position and size of the uterus hardly changed.
"However, we were able to see displacement of the uterus (upwards) and lengthening of the anterior vaginal wall and hardly any change in the position of the uterus during sexual arousal, unless it is caused by intromission [insertion] of the penis.
* "The fornix of the vagina is any of three vaulted [enclosed] spaces at the top of the vagina, around the cervix of the womb"
The size of the vagina is addressed in the Q&A linked to below:
This information indicates you are perfectly normal. You should not notice a change in the length of your vagina while masturbating.
In the missionary position, the male and female bodies are separated by some distance, meaning the full penis is not inserted; other positions allow for deeper penetration. When a penis is inserted it tends to slip in alongside the cervix, as the cervix projects slightly into the vagina, and is spherically shaped in this area. During intercourse the uterus also moves upward about an inch. The glans of the penis is soft, meaning it will conform somewhat to the shape of the upper vagina and cervix. In comparison, the shape and rigidity of the objects you are inserting, and the angle of insertion, may not allow it to enter as far as a penis could. During intercourse you probably will want to be on top, at least until you figure out how things work for you.
While men prize the length of their penis, there is limited space available within a woman's body. Some women experience pain during deep penetration, because their internal organs are stretched or bumped, while other women enjoy deep penetration, perhaps because their cervix is stimulated. During vaginal delivery, the vagina must dilate considerably, rather than lengthen, meaning the vagina is capable of considerable dilation, and some women like to insert objects with a large diameter during their sexual activities.
Below is an image from the medical article quoted above, showing how the male and female bodies typically fit together during intercourse. The bright white shapes are their bladders. The penis is clearly seen. Note how the uterus, which is located at the tip of the penis, is tilted back and is orientated horizontally, in this example.
From: "Magnetic resonance imaging of male and female genitals during coitus and female sexual arousal" by Willibrord Weijmar Schultz, Pek van Andel, Ida Sabelis, Eduard Mooyaart. BMJ volume 319 18-25 December 1999. www.bmj.com
Don't attempt this yourself, but the most graphic demonstration of the capacity and limitations of the vagina were revealed in some video clips I saw several years ago. In the first, a woman walked into a room fully dressed, proceeded to undress, then removed a full size soda can that was concealed just within her vagina/outer labia. In a second video, she is shown walking along a street prior to reaching under her skirt to extract a small plastic water bottle from her vagina. In a third video, a second woman was shown standing with a soda can inserted into her vagina, but it didn't quite fit all the way inside. In a forth video, a third woman is shown laying down on her back with a soda can inserted into her vagina, which was held in place by her outer labia, as it wouldn't fit entirely inside her vagina. A soda can is 4 1/2 inches in length. Based on these examples, the vagina can receive objects in the neighborhood of this length. The vagina can stretch in diameter to accommodate an infant's head, around 3 3/4 inches (9.5 cm.).