The uterotubal junction is the connection between the endometrial cavity of the

uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The uter ...

and the

fallopian tube The fallopian tubes, also known as uterine tubes, oviducts or salpinges (singular salpinx), are paired tubes in the human female that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In ot ...

(uterine tube) at the proximal tubal opening, the beginning of the intramural part of the fallopian tube. Histologically, the endometrial

epithelium Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellul ...

changes over to

cilia The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projecti ...

ted tubal epithelium.

Function

Patency of the uterotubal junction is necessary for normal reproduction. The tubes can get blocked here by infection (

salpingitis Salpingitis is an infection causing inflammation in the Fallopian tubes (also called ''salpinges''). It is often included in the umbrella term of pelvic inflammatory disease (PID), along with endometritis, oophoritis, myometritis, parametritis, ...

) and surgical intervention may be necessary. Mouse studies have indicated that selective passage of individual

spermatozoa A spermatozoon (; also spelled spermatozoön; ; ) is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, ...

may occur at this junction, with abnormal morphology being identified as a significant selection criterion, leading to predominantly normal

sperm Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, whi ...

passing towards the

ovum The egg cell, or ovum (plural ova), is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is ...

. Absence of the protein

calmegin Calmegin, also known as CLGN, is a protein which in humans is encoded by the ''CLGN'' gene. Calmegin is also present in other animals including mice. Function Calmegin is a testis-specific endoplasmic reticulum chaperone protein In molecular ...

has also been suggested as a critical factor for reliable sperm passage.

Other

The uterotubal junction is accessible by

hysteroscopy Hysteroscopy is the inspection of the uterine cavity by endoscopy with access through the cervix. It allows for the diagnosis of intrauterine pathology and serves as a method for surgical intervention (operative hysteroscopy). Hysteroscope A hyst ...

and the entry point for tubal

cannulation A cannula (; Latin meaning 'little reed'; plural or ) is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of samples. In simple terms, a cannula can surround the inner or outer surfaces ...

and

falloposcopy Falloposcopy (occasionally also falloscopy) is the inspection of the fallopian tubes through a micro- endoscope. The falloposcope is inserted into the tube through its opening in the uterus at the proximal tubal opening via the uterotubal junction ...

. Contraceptive methods have been developed to block the uterotubal junction.

References

Pelvis Uterus {{human-repro-stub