Cervix

Function

The cervix is the uterus' gatekeeper — a fibromuscular neck whose mucus tells the story of the cycle: thick and impenetrable for most of the month, then oestrogen makes it thin, stretchy and sperm-permissive at ovulation. In labour it effaces and dilates from a closed slit to 10 cm of passage.

Its transformation zone — where the glandular endocervical epithelium meets the squamous ectocervix — is the cellular borderland where HPV drives the sequence to cancer, and therefore the exact target of Pap smear and HPV screening.

Blood supply

Uterine artery's cervical branches.

Nerve supply

Autonomic uterovaginal plexus; visceral afferents from the cervix travel with the pelvic splanchnic nerves (S2–S4).

Clinical relevance

Cervical cancer

HPV vaccination prevents it; screening catches its precursors — one of oncology's clearest success stories.

Cervical incompetence

A weak cervix opens silently mid-pregnancy — a cerclage suture can hold the pregnancy.

Related conditions

• Cervical cancer