Uterine tube (fallopian tube)

Tuba uterina (salpinx)

Also known as: fallopian tube, oviduct, salpinx, fimbriae, ampulla, infundibulum

A paired muscular tube ≈10–12 cm long running in the upper edge of the broad ligament from the uterus to the ovary, which captures the ovulated oocyte, is the site of fertilisation, and transports the early embryo to the uterus.

Show on body map Female Reproductive Organs

Overview

Length≈10–12 cm

Embryo transit≈3–4 days

Each tube runs laterally from the uterine horn (cornu) in the free upper border of the broad ligament (mesosalpinx), then arches over the ovary. It has four parts, lateral to medial: the funnel-shaped infundibulum, opening into the peritoneal cavity by the abdominal ostium and fringed by finger-like fimbriae (one, the ovarian fimbria, attaches to the ovary); the ampulla — the widest and longest part (over half the length), thin-walled with an elaborately folded mucosa — where fertilisation usually occurs; the narrow, thick-walled isthmus; and the intramural (uterine) part, which passes through the myometrium to open into the uterine cavity at the uterine ostium.

The wall has a mucosa of simple columnar epithelium containing ciliated cells (beating towards the uterus; most numerous in the infundibulum and ampulla, and increased by estrogen) and non-ciliated secretory (peg) cells that produce a nutritive fluid; a muscularis of inner circular and outer longitudinal smooth muscle; and a serosa. At ovulation the fimbriae sweep over the ovary to capture the cumulus–oocyte complex; cilia and peristalsis then move it towards the ampulla. After fertilisation the embryo takes ≈3–4 days to reach the uterus, entering as a morula/early blastocyst.

Location: Upper free margin of the broad ligament, from the superolateral angle of the uterus to the lateral pelvic wall, arching over the ovary.

Parts & subdivisions

Infundibulum with fimbriae
Funnel opening into the peritoneal cavity; fimbriae capture the oocyte. Probable origin of many high-grade serous "ovarian" carcinomas.
Ampulla
Widest, longest segment; usual site of fertilisation and of ectopic pregnancy.
Isthmus
Narrow, thick muscular segment near the uterus; usual site of tubal sterilisation clips.
Intramural (interstitial) part
Within the myometrium; ectopic pregnancy here ruptures late with heavy bleeding.

Anatomy

Innervation: Ovarian and uterine (inferior hypogastric) plexuses; visceral pain fibres accompany sympathetic nerves to ≈T10–L1 (periumbilical and suprapubic referred pain).
Arterial supply: Tubal branches of the uterine artery (medial) and the ovarian artery (lateral), anastomosing in the mesosalpinx.
Venous drainage: Corresponding veins to the uterine and pampiniform/ovarian venous plexuses.
Lymphatic drainage: Mainly to para-aortic (lumbar) nodes with the ovarian vessels; medial part with the uterine lymphatics to iliac nodes.
Histology: Mucosa thrown into branching longitudinal folds (most complex in the ampulla) with ciliated and peg cells; two smooth-muscle layers; serosa.
Development: Cranial, unfused portion of the paramesonephric (Müllerian) duct; the abdominal ostium is the duct's original opening into the coelom.

Function

Captures the ovulated oocyte (fimbriae).
Provides the environment for sperm capacitation and fertilisation (ampulla).
Nourishes and transports the zygote/early embryo to the uterus over ≈3–4 days.

Clinical significance

Ectopic pregnancy

Tubal implantation (≈95 % of ectopics), most often in the ampulla; damaged cilia and adhesions after infection delay transport of the embryo.

Pelvic inflammatory disease and tubal infertility

Ascending Chlamydia or gonococcal infection causes salpingitis, tubo-ovarian abscess, adhesions and hydrosalpinx; it is a leading cause of tubal infertility and ectopic pregnancy. Tubal patency is tested by hysterosalpingography, HyCoSy or laparoscopy and dye.

Sterilisation and salpingectomy

Filshie clips on the isthmus or bilateral salpingectomy prevent pregnancy; salpingectomy also reduces the risk of high-grade serous ovarian cancer.

Mnemonics

Segments

I Am In — Infundibulum, Ampulla, Isthmus, Intramural.

Test yourself

Where does fertilisation normally take place?

Infundibulum of the uterine tube
Ampulla of the uterine tube
Isthmus of the uterine tube
Body of the uterus

Answer: Ampulla of the uterine tube

The ampulla — the widest and longest segment of the tube — is the usual site of fertilisation and also the commonest site of tubal ectopic pregnancy.