Vagina

Function

The vagina is a 7–10 cm muscular canal from the cervix to the vestibule — both the birth canal and the outflow for menstruation. Its rugae-lined walls distend remarkably; its lactobacilli ferment glycogen to lactic acid, holding a protective pH of 3.8–4.5 against pathogens.

Its support comes from the levator ani below and the cardinal-uterosacral complex above; the anterior wall shares the vesicovaginal septum with the bladder, the posterior wall the rectovaginal septum with the rectum — the planes of pelvic surgery and of prolapse.

Blood supply

Vaginal arteries from the internal iliac; uterine anastomoses.

Nerve supply

Upper vagina: autonomic uterovaginal plexus (relatively insensitive to pain); lower vagina: pudendal nerve (somatic sensation).

Clinical relevance

Vaginal prolapse

Weakened support lets the walls bulge — cystocele anteriorly, rectocele posteriorly.

Atrophic vaginitis

Postmenopausal oestrogen loss thins the epithelium — dryness and dyspareunia that topical oestrogen reverses.

Related conditions

• Vaginal thrush (candidiasis)