The vagina is a stretchy, muscular canal located inside the body that connects the external genitals to the uterus. It plays a central role in menstruation, sexual intercourse, and childbirth. Despite being one of the most commonly referenced parts of the body, it’s frequently confused with the vulva, which is actually the outer portion of the genitals. Understanding the difference, and how the vagina works, helps you take better care of your body overall.
Vagina vs. Vulva: They’re Not the Same
One of the most widespread misconceptions is using “vagina” to describe everything between your legs. The vagina is an internal canal. The vulva is everything you can see on the outside: the labia (the folds of skin), the clitoris, the urethral opening (where urine exits), and the vaginal opening itself. When people talk about the “vagina” in everyday conversation, they’re usually referring to the vulva or the entire genital area.
Basic Anatomy of the Vaginal Canal
You can think of the vagina as having three main parts. At the top, it connects to the cervix, a small, firm structure that acts as the gateway between the vagina and the uterus. The middle portion consists of the vaginal walls, which are lined with folds of tissue that allow the canal to stretch. At the bottom is the vaginal opening, which is part of the vulva.
In its resting state, the vaginal canal isn’t a wide-open tunnel. MRI studies of women of reproductive age found that the average length from cervix to opening is roughly 63 millimeters, or about 2.5 inches. The canal is widest near the cervix (about 33 mm) and narrowest at the opening (about 26 mm). These are baseline measurements. During arousal or childbirth, the vagina expands significantly because its walls are made of elastic, muscular tissue designed to stretch and return to shape.
How the Vagina Supports Itself
The vagina doesn’t just float inside the pelvis. It sits between the bladder in front and the rectum behind, and it’s held in place by a network of muscles collectively known as the pelvic floor. The largest of these is the levator ani, a broad muscle that forms a horizontal shelf supporting the upper two-thirds of the vagina, the uterus, and the rectum. Parts of this muscle insert directly into the vaginal walls, giving the canal structural support.
Below the levator ani, a second layer of muscle helps close the opening of the pelvic floor and has a sphincter-like effect on the lower vagina. A fibrous structure called the perineal body, located between the vaginal opening and the anus, anchors several of these muscles together. Keeping pelvic floor muscles strong through regular exercise (sometimes called Kegel exercises) supports bladder control, sexual sensation, and overall pelvic stability.
Self-Cleaning and the Vaginal Microbiome
The vagina maintains its own internal environment without any help from soaps, douches, or cleaning products. Several defense mechanisms work together: a protective layer of mucus, the regular shedding of cells lining the vaginal walls, and a community of beneficial bacteria that keep harmful organisms in check.
The most important of these bacteria are Lactobacillus species. They break down a sugar called glycogen, which is naturally present in vaginal tissue, and convert it into lactic acid. This process keeps the vaginal pH between 3.8 and 5.0 for women of childbearing age, making the environment acidic enough to suppress the growth of most harmful bacteria and sexually transmitted pathogens. Before puberty and after menopause, when estrogen levels are lower, the pH tends to be slightly higher.
This is exactly why douching is discouraged. Flushing the vaginal canal with water, vinegar, or scented products disrupts the Lactobacillus population and raises the pH, which can actually increase the risk of infection rather than prevent it. The vulva can be gently cleaned with warm water, but the vagina itself needs no intervention.
Lubrication and Sexual Function
During sexual arousal, increased blood flow to the vaginal walls causes fluid to pass through the tissue and onto the surface of the canal. This process, called transudation, is the primary source of vaginal lubrication. Additional fluid comes from glands near the vaginal opening (Bartholin’s glands) and from the cervix and uterus. The amount of lubrication varies from person to person and can be affected by hormonal changes, stress, medications, and hydration levels.
Common Vaginal Conditions
Two of the most frequent vaginal issues are bacterial vaginosis (BV) and yeast infections. Both involve imbalances in the vaginal ecosystem, but they’re caused by different things and feel different.
BV happens when the balance of bacteria shifts away from Lactobacillus toward other types of bacteria. The hallmark sign is a thin, grayish discharge with a noticeable change in odor, often more apparent after a menstrual period or intercourse. BV can cause irritation but typically doesn’t cause pain.
Yeast infections are caused by an overgrowth of a fungus called Candida. They produce a thick, white, cottage cheese-like discharge and tend to cause significant itching, burning, and sometimes pain during intercourse. If yeast infections happen three or more times a year, they’re classified as recurrent and may need a different treatment approach. Both conditions are extremely common, and neither one means something is wrong with your hygiene.
Cervical Screening Guidelines
Routine cervical screening is the primary way to monitor vaginal and cervical health over time. Current guidelines recommend that women between ages 21 and 29 get a Pap test every three years. From age 30 to 65, the preferred approach is a test for high-risk HPV strains every five years, or a combination of the Pap test and HPV test every five years. For women 30 and older, self-collected HPV testing is now an accepted option. Women at average risk don’t need screening more often than every three years, and screening typically isn’t recommended after age 65 for those with a history of normal results.