The cervical canal is the spindle-shaped, flattened canal of the

cervix The cervix or cervix uteri (Latin, 'neck of the uterus') is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long (~1 inch) and roughly cylindrical in shape, which changes during ...

, the neck 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 ...

Anatomy

The cervical canal communicates with the

uterine cavity The uterine cavity is the inside of the uterus. It is triangular in shape, the base (broadest part) being formed by the internal surface of the body of the uterus between the openings of the fallopian tubes, the apex by the internal orifice of the ...

via the internal orifice of the uterus (or internal os) and with the

vagina In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...

via the external orifice of the uterus (

ostium An ostium (plural ostia) in anatomy is a small opening or orifice. Ostium or ostia may refer to: Human anatomy * Ostium of fallopian tube * Ostium of the uterus (disambiguation) * Ostium primum of the developing heart * Ostium secundum ( foramen ...

of uterus or external os). The internal orifice of the uterus is an interior narrowing of the uterine cavity. It corresponds to a slight constriction known as the ''isthmus'' that can be seen on the surface of the

about midway between the apex and base. The external orifice of the uterus is a small, depressed, somewhat circular opening on the rounded extremity of the

, opening to the vagina. Through this aperture, the cervical cavity communicates with that of the vagina. The external orifice is bounded by two lips, an anterior and a posterior. The anterior is shorter and thicker, though it projects lower than the posterior because of the slope of the cervix. Normally, both lips are in contact with the posterior vaginal wall. Prior to pregnancy the external orifice has a rounded shape when viewed through the vaginal canal (as through a speculum). Following

childbirth Childbirth, also known as labour and delivery, is the ending of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million births globall ...

, the orifice takes on an appearance more like a transverse slit or is "H-shaped". The wall of the canal presents an anterior and a posterior longitudinal ridge, from each of which proceed a number of small oblique columns, the ''palmate folds'', giving the appearance of branches from the stem of a tree; to this arrangement the name ''arbor vitae uteri'' is applied. The folds on the two walls are not exactly opposed, but fit between one another so as to close the cervical canal.

Histology

The cervical canal is generally lined by "endocervical mucosa" which consists of a single layer of mucinous columnar epithelium. However, after menopause, the functional

squamocolumnar junction The cervix or cervix uteri (Latin, 'neck of the uterus') is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long (~1 inch) and roughly cylindrical in shape, which changes during ...

moves into the cervical canal, and hence the distal part of the cervical canal may be lined by stratified squamous epithelium (conforming to a "type 3 transformation zone").

Pathology

The endocervical mucosa is a site from which

adenocarcinoma Adenocarcinoma (; plural adenocarcinomas or adenocarcinomata ) (AC) is a type of cancerous tumor that can occur in several parts of the body. It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or ...

can arise. Endocervical adenocarcinoma, like cervical cancer (squamous cell carcinoma), often arises in the

milieu The social environment, social context, sociocultural context or milieu refers to the immediate physical and social setting in which people live or in which something happens or develops. It includes the culture that the individual was educate ...

human papilloma virus Human papillomavirus infection (HPV infection) is caused by a DNA virus from the ''Papillomaviridae'' family. Many HPV infections cause no symptoms and 90% resolve spontaneously within two years. In some cases, an HPV infection persists and res ...

infection. As most

endometrial cancer Endometrial cancer is a cancer that arises from the endometrium (the lining of the uterus or womb). It is the result of the abnormal growth of cells that have the ability to invade or spread to other parts of the body. The first sign is most o ...

s are adenocarcinomas, differentiation of endocervical adenocarcinoma and endometrial adenocarcinomas is required, as the treatment differs.

Immunohistochemical staining Immunohistochemistry (IHC) is the most common application of immunostaining. It involves the process of selectively identifying antigens (proteins) in cells of a tissue section by exploiting the principle of antibodies binding specifically to ant ...

is often helpful in this regard, endocervical adenocarcinomas are typically CEA and

p16 p16 (also known as p16INK4a, cyclin-dependent kinase inhibitor 2A, CDKN2A, multiple tumor suppressor 1 and numerous other synonyms), is a protein that slows cell division by slowing the progression of the cell cycle from the G1 phase to the S p ...

positive and

estrogen receptor Estrogen receptors (ERs) are a group of proteins found inside cells. They are receptors that are activated by the hormone estrogen ( 17β-estradiol). Two classes of ER exist: nuclear estrogen receptors (ERα and ERβ), which are members of the ...

progesterone receptor The progesterone receptor (PR), also known as NR3C3 or nuclear receptor subfamily 3, group C, member 3, is a protein found inside cells. It is activated by the steroid hormone progesterone. In humans, PR is encoded by a single ''PGR'' gene resid ...

and

vimentin Vimentin is a structural protein that in humans is encoded by the ''VIM'' gene. Its name comes from the Latin ''vimentum'' which refers to an array of flexible rods. Vimentin is a type III intermediate filament (IF) protein that is expressed ...

negative.

References

{{DEFAULTSORT:Canal Of The Cervix Mammal female reproductive system

Anatomy

Histology

Pathology

See also

References