Vagina

The vagina is a muscular, elastic canal, about 8-10 cm long, extending from the cervix down to the vulva. It serves as the passage for menstrual flow, for intercourse and for childbirth. Its lining is folded (rugae) so it can stretch greatly, kept moist and mildly acidic by secretions and by lactobacillus bacteria — an environment that discourages harmful microbes. Its upper end forms pouches (fornices) around the cervix.

Key facts

The vagina's acidity (pH about 3.8-4.5 in adults) is maintained by lactobacilli feeding on glycogen in its cells.
It has no glands of its own; moisture comes from fluid seeping through its wall and from cervical mucus.
The pelvic floor muscles surround its lower third and give voluntary control.
Its lining thickens under estrogen and thins after the menopause, which is why dryness is common then.

What can go wrong

Common vaginal problems include thrush (candida), bacterial vaginosis (an imbalance of its normal flora), and sexually transmitted infections. After the menopause, thinning of the lining (vaginal atrophy) causes dryness, soreness and sometimes bleeding. Weakened supports can let the vaginal walls bulge (prolapse). Persistent discharge, itching, sores or bleeding are assessed by examination and swab tests.

Related conditions

Related procedures & tests

Related symptoms

Frequently asked questions

Is vaginal discharge normal?

Yes — a clear or white discharge that varies across the cycle is normal and keeps the vagina healthy; changes in colour, smell, itching or soreness suggest infection and are worth checking.

Why is the vagina acidic?

Lactobacillus bacteria dominate its flora and produce lactic acid; the acidity inhibits many pathogens, which is why disrupting the flora can lead to infections.

Educational information only. This atlas explains normal anatomy and describes conditions in general terms; it is not medical advice and does not replace assessment by a qualified clinician. If you have symptoms that worry you, seek medical care.