From a certain point of view, female external genitalia and breasts, is the most mysterious place on the body of women visible, touchable, then, this flavorful, gentle and infinite Eden, whether it really hides the mystery that makes the flirtatious men obsessed with it or rushed to the top? Stuck with the scale, get to know. Last time we told about the upstream neighbor of the uterus, only the size of a bullet, but the ovaries of the Queen Mother level energy. Thanks to more than 800 retweets, it made me keep my word and move on with passion to talk about the downstream neighbors of the uterus: the vagina and vulva, and the more distant neighbors, the breasts. Anatomically speaking, the vagina is already part of the female internal genitalia. The textbook Obstetrics and Gynecology defines the vagina as the organ of sexual intercourse and the channel for the discharge of menstrual blood and the delivery of the fetus. This definition is interesting and intriguing. Please pay attention to the word “also”, because this one word clearly defines the primary and secondary functions of the vagina, and the criteria for ranking them is frequency of use. Let’s assume that women start menstruating at the age of 12 and menopause at 52, which is about 40 years of reproductive time. The number of times the vagina is used as a channel for the delivery of a fetus (births) does not exceed 40; the number of times it is used as a channel for the discharge of menstruation averages about 500 (40 years times 12 months); but the number of times it is used as an organ of sexual intercourse, some newlyweds break this figure in 1 year, at most 3 years! In the digital age, everything speaks in numbers, and I have to say that this definition is really accurate. Do you have some or the most? The vagina is located in the center of the lower part of the true pelvis and is a wide upper and narrow lower canal that is normally closed and has an “H” shaped cross-section. In general, the anterior wall of the vagina is slightly longer than a woman’s index finger (7cm-9cm) and is adjacent to the bladder; the posterior wall is slightly longer than the length of the middle finger (10cm-12cm) and is close to the rectum. It is possible for a woman to feel the cervix and the end of the vagina (the vault) with her hand. Although the fingertips may not be long enough for this length, the vulva is very elastic and will be much indented. The upper part of the vagina wraps around the cervix and the lower part opens at the back of the vestibule with a membrane called the “hymen”. There are 1,000 stories of misconceptions about the relationship between the hymen and female chastity, but they are beyond the scope of this article, so I won’t go into them at length. The vaginal wall is composed of a mucous membrane, a muscular layer and a fibrous tissue membrane from the inside out. The mucosal layer is covered by a non-keratinized (the nails are typically keratinized), fish-scale like arrangement of epithelium (compound squamous epithelium) that is light red in color with many transverse folds. It is because of these transverse folds that the vagina is very stretchable. How stretchy is the vagina? If you don’t know, you’ll be surprised: during vaginal delivery, the vagina can stretch to the size of the fetal head (about 10 cm in diameter). Once when I saw an oddball friend online showing off how majestic and spectacular a part of herself was in front of women, I almost commented, “Dude, if you have time to take a tour of the delivery room, you’ll know that any woman can destroy you, be modest!” The muscle layer of the vaginal wall consists of two layers of smooth muscle (vaginal sphincter) in the inner and outer longitudinal rings. There are 3 types of muscles in the human body, the first one is the cardiac muscle, which can contract and diastole on its own and is innervated by sympathetic and parasympathetic (autonomic) nerves, not by somatic nerves. In other words, you can’t control the heart rate like you can control your arms and legs! The second type is smooth muscle, including the muscles of the intestines, vagina and urethra, which are also innervated by autonomic nerves and which you cannot consciously dominate. Normally a woman cannot actively make the smooth muscle of the vagina contract, but at the soulful moment of love and orgasm, the smooth muscle of the vagina will contract involuntarily, just like a stubborn hiccup, and it’s hard to keep it from contracting! But why do doctors recommend anal reduction exercises for older women who have a prolapsed pelvic organ and cannot control their urine (incontinence), or for women whose husbands complain that they are not as tight as before after giving birth? This is because the lower part of a woman’s vagina, adjacent to the vaginal opening, is reinforced on the outside of the sphincter by a muscle called the “levator ani”. Want to know where the levator muscle is located? Try doing an anal retraction, that is, when you are in a big hurry, but the only pit is occupied, you have to tighten a part of the body to avoid erupting, that part of the muscle is the anal raphe. It belongs to the third category of muscles in the body: the transverse muscle. This muscle, like the muscles of the limbs, is innervated by the somatic nerves. The smooth muscle tissue of the vagina is exercised during the active contraction of the anus for anal lifting. The anal retraction exercise is a kind of unconscious fitness exercise, even if your boss is giving orders or the speaker is talking, you can complete this fitness exercise without spending a penny. Generally speaking, if you do 3 times a day, each contraction at least 100, then after 3 months must be a small success. I once sent out this microblogging small exercise, big effect: six months ago, a young woman came to my clinic, saying that after the birth of a child, her husband complained of feeling much less than before, to do tightening surgery. I examined her and dismissed it, joking that her husband should have an enlargement surgery! She was advised to do anal tightening exercises at least 3 times a day, which would definitely work wonders. Recently, she came for a follow-up and said her husband felt great! Oh, I thought, the man called Kegel invented the method, not too much to win a Nobel Prize! Since the primary definition of the vagina in anatomy is the organ of intercourse, I hope that neither Taoists nor sexologists will shoot the bricks when I tell you about the female orgasm here. Suffice it to say that if a woman achieves an orgasm, but for some reason has to pretend that she didn’t is very difficult. Because as you can see from the physiology of the heart and smooth muscles mentioned earlier, when it really comes to the moment of pinning, the female heartbeat will involuntarily speed up, and the vaginal and anal sphincters will involuntarily contract and cannot be controlled on their own (of course, the more saintly women may not want to control it at this point). Conversely, if a woman does not reach orgasm, it is easy to fake it for some reason. First of all, the special sound of the woman’s voice, which is known as one of the most beautiful music in the world, can be controlled and disguised; secondly, the involuntary contraction of the vaginal sphincter can be controlled by the active contraction of the anal raphe to simulate the involuntary contraction of the vaginal sphincter; and finally, the woman can use other body language and encouraging words to make the man feel confident, which is also easy to do. But please note that the speed of the heartbeat is mostly uncontrollable. So it seems that women are really great, for the sake of the poor male vanity, how careful it needs to be, how much effort! I would like to take this opportunity to advise my fellow men not to add to her pulse when you are feeling very proud and proud, maybe which will let you down. The human world is already very difficult, why bother to tear yourself apart? Sexologists say the vagina is one of the key building blocks of the female orgasm, saying that in Lawrence’s controversial novel Lady Chatterley’s Lover, it is the vaginal orgasm that the feisty forest keeper lets Lady Chatterley drift off to. Sexologists say there is a point in the vagina that triggers orgasm, called the “G-spot”. The G-spot is a highly sensitive area on the front wall of the vagina near the vaginal opening <2 cm to 3 cm (1/3 of the way inward from the outside of the vagina), which is prone to orgasm when pressure is applied. The size of the G-spot varies from person to person and is generally equivalent to the size of a penny. Sexologists say that the G-spot is not universal and that only 10-40% of women have it. It is generally believed that women with a G-spot are more sensual during sex and orgasms come more quickly. But philosophers say that love is a union of spirit and flesh, and that the G-spot is not in a woman's vagina, but in her heart. If a woman has sex with someone she loves, there is a G-spot everywhere; if she is not in love, there is a G-spot for nothing. Sexologists also say that there are clitoral orgasms, where women can have orgasms without the penetration and friction of the penis in the vagina.