The Fallopian (Uterine) Tubes
The uterine tubes (or fallopian tubes, oviducts, salpinx) are muscular ‘J-shaped’ tubes, found in the female reproductive tract.
They lie in the upper border of the broad ligament, extending laterally from the uterus, opening into the abdominal cavity, near the ovaries.
This article will look at the function, parts, vasculature and innervation of the fallopian tubes, as well as any clinical relevance.
The main function of the uterine tubes is to assist in the transfer and transport of the ovum from the ovary, to the uterus.
The ultra-structure of the uterine tubes facilitates the movement of the female gamete:
- The inner mucosa is lined with ciliated columnar epithelial cells and peg cells (non-ciliated secretory cells). They waft the ovum towards the uterus and supply it with nutrients.
- Smooth muscle layer contracts to assist with transportation of the ova and sperm. Muscle is sensitive to sex steroids, and thus peristalsis is greatest when oestrogen levels are high.
The fallopian tube is described as having four parts (lateral to medial);
- Fimbriae – finger-like, ciliated projections which capture the ovum from the surface of the ovary.
- Infundibulum – funnel-shaped opening near the ovary to which fimbriae are attached.
- Ampulla – widest section of the uterine tubes. Fertilization usually occurs here.
- Isthmus – narrow section of the uterine tubes connecting the ampulla to the uterine cavity.
Vascular Supply and Lymphatics
The arterial supply to the uterine tubes is via the uterine and ovarian arteries. Venous drainage is via the uterine and ovarian veins.
Lymphatic drainage is via the iliac, sacral and aortic lymph nodes.
The uterine tubes receive both sympathetic and parasympathetic innervation via nerve fibres from the ovarian and uterine (pelvic) plexuses. Sensory afferent fibres run from T11- L1.
Salpingitis is inflammation of the uterine tubes that is usually caused by bacterial infection. It can cause adhesions of the mucosa which may partially or completely block the lumen of the uterine tubes. This can potentially result in infertility or an ectopic pregnancy.
If the lumen of the uterine tube is partially occluded, sperm may be able to pass through and fertilise the ovum. However, the fertilised egg may not be able to pass into the uterus, and can implant in the uterine tube. This is known as an ectopic pregnancy.
An ectopic pregnancy is a medical emergency – if not diagnosed early, the implanted blastocyst can cause rupture and haemorrhage of the affected tube.
Ligation of the Uterine Tubes
Surgical cutting of the uterine tubes is a method of sterilisation. The oocyte is unable to pass into the uterus, and therefore cannot progress to a pregnancy.
There are two main methods of ligation:
- Open abdominal – Carried out via a suprapubic incision (see here for more information about surgical incisions through the abdominal wall).
- Laproscopic – Carried out via a fibre optic laproscope, inserted via a small incision near the umbilicus.