Cervix

The cervix or cervix uteri (Latin: neck of the uterus) is the lower part of the uterus 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 pregnancy. The narrow, central cervical canal runs along its entire length, connecting the uterine cavity and the lumen of the vagina. The opening into the uterus is called the internal os, and the opening into the vagina is called the external os. The lower part of the cervix, known as the vaginal portion of the cervix (or ectocervix), bulges into the top of the vagina. The cervix has been documented anatomically since at least the time of Hippocrates, over 2,000 years ago.

The cervical canal is a passage through which sperm must travel to fertilize an egg cell after sexual intercourse. Several methods of contraception, including cervical caps and cervical diaphragms, aim to block or prevent the passage of sperm through the cervical canal. Cervical mucus is used in several methods of fertility awareness, such as the Creighton model and Billings method, due to its changes in consistency throughout the menstrual period. During vaginal childbirth, the cervix must flatten and dilate to allow the fetus to progress along the birth canal. Midwives and doctors use the extent of the dilation of the cervix to assist decision-making during childbirth.

The cervical canal is lined with a single layer of column-shaped cells, while the ectocervix is covered with multiple layers of cells topped with flat cells. The two types of epithelia meet the squamocolumnar junction. Infection with the human papillomavirus (HPV) can cause changes in the epithelium, which can lead to cancer of the cervix. Cervical cytology tests can often detect cervical cancer and its precursors, and enable early successful treatment. Ways to avoid HPV include avoiding sex, using condoms, and HPV vaccination. HPV vaccines, developed in the early 21st century, reduce the risk of cervical cancer by preventing infections from the main cancer-causing strains of HPV.[1]

Cervix
Scheme female reproductive system-en
The human female reproductive system. The cervix is the lower narrower portion of the uterus.
Details
PrecursorMüllerian duct
ArteryVaginal artery and uterine artery
Identifiers
LatinCervix uteri
MeSHD002584
TAA09.1.03.010
FMA17740
Anatomical terminology

Structure

Gray1167
Diagram of the uterus and part of the vagina. The cervix is the lower part of the uterus situated between the external os (external orifice) and internal os (internal orifice). The cervical canal connects the interior of the vagina and the cavity of the body of uterus.

The cervix is part of the female reproductive system. Around 2–3 centimetres (0.8–1.2 in) in length,[2] it is the lower narrower part of the uterus continuous above with the broader upper part—or body—of the uterus.[3] The lower end of the cervix bulges through the anterior wall of the vagina, and is referred to as the vaginal portion of cervix (or ectocervix) while the rest of the cervix above the vagina is called the supravaginal portion of cervix.[3] A central canal, known as the cervical canal, runs along its length and connects the cavity of the body of the uterus with the lumen of the vagina.[3] The openings are known as the internal os and external orifice of the uterus (or external os) respectively.[3] The mucosa lining the cervical canal is known as the endocervix,[4] and the mucosa covering the ectocervix is known as the exocervix.[5] The cervix has an inner mucosal layer, a thick layer of smooth muscle, and posteriorly the supravaginal portion has a serosal covering consisting of connective tissue and overlying peritoneum.[3]

Cervix
A normal cervix of an adult viewed using a bivalved vaginal speculum. The functional squamocolumnar junction surrounds the external os and is visible as the irregular demarcation between the lighter and darker shades of pink mucosa.

In front of the upper part of the cervix lies the bladder, separated from it by cellular connective tissue known as parametrium, which also extends over the sides of the cervix.[3] To the rear, the supravaginal cervix is covered by peritoneum, which runs onto the back of the vaginal wall and then turns upwards and onto the rectum, forming the recto-uterine pouch.[3] The cervix is more tightly connected to surrounding structures than the rest of the uterus.[6]

The cervical canal varies greatly in length and width between women or over the course of a woman's life,[2] and it can measure 8 mm (0.3 inch) at its widest diameter in premenopausal adults.[7] It is wider in the middle and narrower at each end. The anterior and posterior walls of the canal each have a vertical fold, from which ridges run diagonally upwards and laterally. These are known as palmate folds, due to their resemblance to a palm leaf. The anterior and posterior ridges are arranged in such a way that they interlock with each other and close the canal. They are often effaced after pregnancy.[6]

The ectocervix (also known as the vaginal portion of the cervix) has a convex, elliptical shape and projects into the cervix between the anterior and posterior vaginal fornices. On the rounded part of the ectocervix is a small, depressed external opening, connecting the cervix with the vagina. The size and shape of the ectocervix and the external opening (external os) can vary according to age, hormonal state, and whether natural or normal childbirth has taken place. In women who have not had a vaginal delivery, the external opening is small and circular, and in women who have had a vaginal delivery, it is slit-like.[7] On average, the ectocervix is 3 cm (1.2 in) long and 2.5 cm (1 in) wide.[2]

Blood is supplied to the cervix by the descending branch of the uterine artery[8] and drains into the uterine vein.[9] The pelvic splanchnic nerves, emerging as S2S3, transmit the sensation of pain from the cervix to the brain.[4] These nerves travel along the uterosacral ligaments, which pass from the uterus to the anterior sacrum.[8]

Three channels facilitate lymphatic drainage from the cervix.[10] The anterior and lateral cervix drains to nodes along the uterine arteries, travelling along the cardinal ligaments at the base of the broad ligament to the external iliac lymph nodes and ultimately the paraaortic lymph nodes. The posterior and lateral cervix drains along the uterine arteries to the internal iliac lymph nodes and ultimately the paraaortic lymph nodes, and the posterior section of the cervix drains to the obturator and presacral lymph nodes.[2][9][10] However, there are variations as lymphatic drainage from the cervix travels to different sets of pelvic nodes in some people. This has implications in scanning nodes for involvement in cervical cancer.[10]

After menstruation and directly under the influence of estrogen, the cervix undergoes a series of changes in position and texture. During most of the menstrual cycle, the cervix remains firm, and is positioned low and closed. However, as ovulation approaches, the cervix becomes softer and rises to open in response to the higher levels of estrogen present.[11] These changes are also accompanied by changes in cervical mucus,[12] described below.

Development

As a component of the female reproductive system, the cervix is derived from the two paramesonephric ducts (also called Müllerian ducts), which develop around the sixth week of embryogenesis. During development, the outer parts of the two ducts fuse, forming a single urogenital canal that will become the vagina, cervix and uterus.[13] The cervix grows in size at a smaller rate than the body of the uterus, so the relative size of the cervix over time decreases, decreasing from being much larger than the body of the uterus in fetal life, twice as large during childhood, and decreasing to its adult size, smaller than the uterus, after puberty.[9] Previously it was thought that during fetal development, the original squamous epithelium of the cervix is derived from the urogenital sinus and the original columnar epithelium is derived from the paramesonephric duct. The point at which these two original epithelia meet is called the original squamocolumnar junction.[14]:15–16 New studies show, however, that all the cervical as well as large part of the vaginal epithelium are derived from Müllerian duct tissue and that phenotypic differences might be due to other causes.[15]

Histology

Cervix Normal Squamocolumnar Junction (565238127)
The squamocolumnar junction of the cervix: The ectocervix, with its stratified squamous epithelium, is visible on the left. Simple columnar epithelium, typical of the endocervix, is visible on the right. A layer of connective tissue is visible under both types of epithelium.

The endocervical mucosa is about 3 millimetres (0.12 in) thick, lined with a single layer of columnar mucous cells, and contains numerous tubular mucous glands which empty viscous alkaline mucus into the lumen.[3] In contrast, the ectocervix is covered with nonkeratinized stratified squamous epithelium,[3] which resembles the squamous epithelium lining the vaginal.[16]:41 The junction between these two types of epithelia is called the squamocolumnar junction.[16]:408–11 Underlying both types of epithelium is a tough layer of collagen.[17] The mucosa of the endocervix is not shed during menstruation.[3] The cervix has more fibrous tissue, including collagen and elastin, than the rest of the uterus.[3]

Nulliparous cervix with ectropion
A nulliparous woman's ectocervix showing Cervical ectropion, visible as the darker red mucosa surrounding the cervical os. Viewed on speculum exam.

In prepubertal girls, the functional squamocolumnar junction is present just within the cervical canal.[16]:411 Upon entering puberty, due to hormonal influence, and during pregnancy, the columnar epithelium extends outwards over the ectocervix as the cervix everts.[14]:106 Hence, this also causes the squamocolumnar junction to move outwards onto the vaginal portion of the cervix, where it is exposed to the acidic vaginal environment.[14]:106[16]:411 The exposed columnar epithelium can undergo physiological metaplasia and change to tougher metaplastic squamous epithelium in days or weeks,[16]:25 which is very similar to the original squamous epithelium when mature.[16]:411 The new squamocolumnar junction is therefore internal to the original squamocolumnar junction, and the zone of unstable epithelium between the two junctions is called the transformation zone of the cervix.[16]:411 After menopause, the uterine structures involute and the functional squamocolumnar junction moves into the cervical canal.[16]:41

Nabothian cysts (or Nabothian follicles) form in the transformation zone where the lining of metaplastic epithelium has replaced mucous epithelium and caused a strangulation of the outlet of some of the mucous glands.[16]:410–411 A buildup of mucus in the glands forms Nabothian cysts, usually less than about 5 mm (0.20 in) in diameter,[3] which are considered physiological rather than pathological.[16]:411 Both gland openings and Nabothian cysts are helpful to identify the transformation zone.[14]:106

Function

Fertility

The cervical canal is a pathway through which sperm enter the uterus after sexual intercourse,[18] and some forms of artificial insemination.[19] Some sperm remains in cervical crypts, infoldings of the endocervix, which act as a reservoir, releasing sperm over several hours and maximising the chances of fertilisation.[20] A theory states the cervical and uterine contractions during orgasm draw semen into the uterus.[18] Although the "upsuck theory" has been generally accepted for some years, it has been disputed due to lack of evidence, small sample size, and methodological errors.[21][22]

Some methods of fertility awareness, such as the Creighton model and the Billings method involve estimating a woman's periods of fertility and infertility by observing physiological changes in her body. Among these changes are several involving the quality of her cervical mucus: the sensation it causes at the vulva, its elasticity (Spinnbarkeit), its transparency, and the presence of ferning.[11]

Cervical mucus

Several hundred glands in the endocervix produce 20–60 mg of cervical mucus a day, increasing to 600 mg around the time of ovulation. It is viscous because it contains large proteins known as mucins. The viscosity and water content varies during the menstrual cycle; mucus is composed of around 93% water, reaching 98% at midcycle. These changes allow it to function either as a barrier or a transport medium to spermatozoa. It contains electrolytes such as calcium, sodium, and potassium; organic components such as glucose, amino acids, and soluble proteins; trace elements including zinc, copper, iron, manganese, and selenium; free fatty acids; enzymes such as amylase; and prostaglandins.[12] Its consistency is determined by the influence of the hormones estrogen and progesterone. At midcycle around the time of ovulation—a period of high estrogen levels— the mucus is thin and serous to allow sperm to enter the uterus, and is more alkaline and hence more hospitable to sperm.[20] It is also higher in electrolytes, which results in the "ferning" pattern that can be observed in drying mucus under low magnification; as the mucus dries, the salts crystallize, resembling the leaves of a fern.[11] The mucus has stretchy character described as Spinnbarkeit most prominent around the time of ovulation.[23]

At other times in the cycle, the mucus is thick and more acidic due to the effects of progesterone.[20] This "infertile" mucus acts as a barrier to sperm from entering the uterus.[24] Women taking an oral contraceptive pill also have thick mucus from the effects of progesterone.[20] Thick mucus also prevents pathogens from interfering with a nascent pregnancy.[25]

A cervical mucus plug, called the operculum, forms inside the cervical canal during pregnancy. This provides a protective seal for the uterus against the entry of pathogens and against leakage of uterine fluids. The mucus plug is also known to have antibacterial properties. This plug is released as the cervix dilates, either during the first stage of childbirth or shortly before.[26] It is visible as a blood-tinged mucous discharge.[27]

Childbirth

Positive Feedback- Childbirth (1)
When the head of the fetus pushes against the cervix, a signal (2) is sent to the brain. This causes a signal to be sent to the pituitary gland to release oxytocin (4) . Oxytocin is carried in the bloodstream to the uterus causing contractions to induce childbirth.

The cervix plays a major role in childbirth. As the fetus descends within the uterus in preparation for birth, the presenting part, usually the head, rests on and is supported by the cervix.[28] As labour progresses, the cervix becomes softer and shorter, begins to dilate, and rotates to face anteriorly.[29] The support the cervix provides to the fetal head starts to give way when the uterus begins its contractions. During childbirth, the cervix must dilate to a diameter of more than 10 cm (3.9 in) to accommodate the head of the fetus as it descends from the uterus to the vagina. In becoming wider, the cervix also becomes shorter, a phenomenon known as effacement.[28]

Along with other factors, midwives and doctors use the extent of cervical dilation to assist decision making during childbirth.[30][31] Generally, the active first stage of labour, when the uterine contractions become strong and regular,[30] begins when the cervical dilation is more than 3–5 cm (1.2–2.0 in).[32][33] The second phase of labor begins when the cervix has dilated to 10 cm (4 in), which is regarded as its fullest dilation,[28] and is when active pushing and contractions push the baby along the birth canal leading to the birth of the baby.[31] The number of past vaginal deliveries is a strong factor in influencing how rapidly the cervix is able to dilate in labour.[28] The time taken for the cervix to dilate and efface is one factor used in reporting systems such as the Bishop score, used to recommend whether interventions such as a forceps delivery, induction, or Caesarean section should be used in childbirth.[28]

Cervical incompetence is a condition in which shortening of the cervix due to dilation and thinning occurs, before term pregnancy. Short cervical length is the strongest predictor of preterm birth.[29]

Contraception

Several methods of contraception involve the cervix. Cervical diaphragms are reusable, firm-rimmed plastic devices inserted by a woman prior to intercourse that cover the cervix. Pressure against the walls of the vagina maintain the position of the diaphragm, and it acts as a physical barrier to prevent the entry of sperm into the uterus, preventing fertilisation. Cervical caps are a similar method, although they are smaller and adhere to the cervix by suction. Diaphragms and caps are often used in conjunction with spermicides.[34] In one year, 12% of women using the diaphragm will undergo an unintended pregnancy, and with optimal use this falls to 6%.[35] Efficacy rates are lower for the cap, with 18% of women undergoing an unintended pregnancy, and 10–13% with optimal use.[36] Most types of progestogen-only pills are effective as a contraceptive because they thicken cervical mucus making it difficult for sperm to pass along the cervical canal.[37] In addition, they may also sometimes prevent ovulation.[37] In contrast, contraceptive pills that contain both oestrogen and progesterone, the combined oral contraceptive pills, work mainly by preventing ovulation.[38] They also thicken cervical mucus and thin the lining of the uterus enhancing their effectiveness.[38]

Clinical significance

Cancer

In 2008, cervical cancer was the third-most common cancer in women worldwide, with rates varying geographically from less than one to more than 50 cases per 100,000 women.[39] It is a leading cause of cancer-related death in poor countries, where delayed diagnosis leading to poor outcomes is common.[40] The introduction of routine screening has resulted in fewer cases of (and deaths from) cervical cancer, however this has mainly taken place in developed countries. Most developing countries have limited or no screening, and 85% of the global burden occurring there.[41]

Cervical cancer nearly always involves human papillomavirus (HPV) infection.[42][43] HPV is a virus with numerous strains, several of which predispose to precancerous changes in the cervical epithelium, particularly in the transformation zone, which is the most common area for cervical cancer to start.[44] HPV vaccines, such as Gardasil and Cervarix, reduce the incidence of cervical cancer, by inoculating against the viral strains involved in cancer development.[45]

Potentially precancerous changes in the cervix can be detected by cervical screening, using methods including a Pap smear (also called a cervical smear), in which epithelial cells are scraped from the surface of the cervix and examined under a microscope.[45] The colposcope, an instrument used to see a magnified view of the cervix, was invented in 1925. The Pap smear was developed by Georgios Papanikolaou in 1928.[46] A LEEP procedure using a heated loop of platinum to excise a patch of cervical tissue was developed by Aurel Babes in 1927.[47] In some parts of the developed world including the UK, the Pap test has been superseded with liquid-based cytology.[48]

A cheap, cost-effective and practical alternative in poorer countries is visual inspection with acetic acid (VIA).[40] Instituting and sustaining cytology-based programs in these regions can be difficult, due to the need for trained personnel, equipment and facilities and difficulties in follow-up. With VIA, results and treatment can be available on the same day. As a screening test, VIA is comparable to cervical cytology in accurately identifying precancerous lesions.[49]

A result of dysplasia is usually further investigated, such as by taking a cone biopsy, which may also remove the cancerous lesion.[45] Cervical intraepithelial neoplasia is a possible result of the biopsy, and represents dysplastic changes that may eventually progress to invasive cancer.[50] Most cases of cervical cancer are detected in this way, without having caused any symptoms. When symptoms occur, they may include vaginal bleeding, discharge, or discomfort.[51]

Inflammation

Inflammation of the cervix is referred to as cervicitis. This inflammation may be of the endocervix or ectocervix.[52] When associated with the endocervix, it is associated with a mucous vaginal discharge and the sexually transmitted infections such as chlamydia and gonorrhoea.[53] As many as half of pregnant women having a gonorrheal infection of the cervix are asymptomatic.[54] Other causes include overgrowth of the commensal flora of the vagina.[43] When associated with the ectocervix, inflammation may be caused by the herpes simplex virus. Inflammation is often investigated through directly visualising the cervix using a speculum, which may appear whiteish due to exudate, and by taking a Pap smear and examining for causal bacteria. Special tests may be used to identify particular bacteria. If the inflammation is due to a bacterium, then antibiotics may be given as treatment.[53]

Anatomical abnormalities

Cervical stenosis refers to an abnormally narrow cervical canal, typically associated with trauma caused by removal of tissue for investigation or treatment of cancer, or cervical cancer itself.[43][55] Diethylstilbestrol, used from 1938 to 1971 to prevent preterm labour and miscarriage, is also strongly associated with the development of cervical stenosis and other abnormalities in the daughters of the exposed women. Other abnormalities include: vaginal adenosis, in which the squamous epithelium of the ectocervix becomes columnar; cancers such as clear cell adenocarcinomas; cervical ridges and hoods; and development of a cockscomb cervix appearance,[56] which is the condition wherein, as the name suggests, the cervix of the uterus is shaped like a cockscomb. About one third of women born to diethylstilbestrol-treated mothers (i.e. in-utero exposure) develop a cockscomb cervix.[57]

Enlarged folds or ridges of cervical stroma (fibrous tissues) and epithelium constitute a cockscomb cervix.[58] Similarly, cockscomb polyps lining the cervix are usually considered or grouped into the same overarching description. It is in and of itself considered a benign abnormality; its presence, however is usually indicative of DES exposure, and as such women who experience these abnormalities should be aware of their increased risk of associated pathologies.[59][60][61]

Cervical agenesis is a rare congenital condition in which the cervix completely fails to develop, often associated with the concurrent failure of the vagina to develop.[62] Other congenital cervical abnormalities exist, often associated with abnormalities of the vagina and uterus. The cervix may be duplicated in situations such as bicornuate uterus and uterine didelphys.[63]

Cervical polyps, which are benign overgrowths of endocervical tissue, if present, may cause bleeding, or a benign overgrowth may be present in the cervical canal.[43] Cervical ectropion refers to the horizontal overgrowth of the endocervical columnar lining in a one-cell-thick layer over the ectocervix.[53]

Other mammals

Female marsupials have paired uteri and cervices.[64][65] Most eutherian (placental) mammal species have a single cervix and single, bipartite or bicornuate uterus. Lagomorphs, rodents, aardvarks and hyraxes have a duplex uterus and two cervices.[66] Lagomorphs and rodents share many morphological characteristics and are grouped together in the clade Glires. Anteaters of the family myrmecophagidae are unusual in that they lack a defined cervix; they are thought to have lost the characteristic rather than other mammals developing a cervix on more than one lineage.[67] In domestic pigs, the cervix contains a series of five interdigitating pads that hold the boar's corkscrew-shaped penis during copulation.[68]

Etymology and pronunciation

The word cervix (/ˈsɜːrvɪks/) came to English from Latin, where it means "neck", and like its Germanic counterpart, it can refer not only to the neck [of the body] but also to an analogous narrowed part of an object. The cervix uteri (neck of the uterus) is thus the uterine cervix, but in English the word cervix used alone usually refers to it. Thus the adjective cervical may refer either to the neck (as in cervical vertebrae or cervical lymph nodes) or to the uterine cervix (as in cervical cap or cervical cancer).

Latin cervix came from the Proto-Indo-European root ker-, referring to a "structure that projects". Thus, the word cervix is linguistically related to the English word "horn", the Persian word for "head" (Persian: سرsar), the Greek word for "head" (Greek: κορυφή koruphe), and the Welsh word for "deer" (Welsh: carw).[69][70]

The cervix was documented in anatomical literature in at least the time of Hippocrates; cervical cancer was first described more than 2,000 years ago, with descriptions provided by both Hippocrates and Aretaeus.[46] However, there was some variation in word sense among early writers, who used the term to refer to both the cervix and the internal uterine orifice.[71] The first attested use of the word to refer to the cervix of the uterus was in 1702.[69]

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Cited texts

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Caput succedaneum

Caput succedaneum is a neonatal condition involving a serosanguinous, subcutaneous, extraperiosteal fluid collection with poorly defined margins caused by the pressure of the presenting part of the scalp against the dilating cervix (tourniquet effect of the cervix) during delivery.

It involves bleeding below the scalp and above the periosteum.

Cervical canal

The cervical canal is the spindle-shaped, flattened canal of the cervix, the neck of the uterus.

It communicates with the uterine cavity via the internal orifice of the uterus (or internal os) and with the vagina via the external orifice of the uterus (ostium 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 uterus 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 cervix, 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 parturition, 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.

Cervical cancer

Cervical cancer is a cancer arising from the cervix. It is due to the abnormal growth of cells that have the ability to invade or spread to other parts of the body. Early on, typically no symptoms are seen. Later symptoms may include abnormal vaginal bleeding, pelvic pain, or pain during sexual intercourse. While bleeding after sex may not be serious, it may also indicate the presence of cervical cancer.Human papillomavirus infection (HPV) causes more than 90% of cases; most people who have had HPV infections, however, do not develop cervical cancer. Other risk factors include smoking, a weak immune system, birth control pills, starting sex at a young age, and having many sexual partners, but these are less important. Cervical cancer typically develops from precancerous changes over 10 to 20 years. About 90% of cervical cancer cases are squamous cell carcinomas, 10% are adenocarcinoma, and a small number are other types. Diagnosis is typically by cervical screening followed by a biopsy. Medical imaging is then done to determine whether or not the cancer has spread.HPV vaccines protect against between two and seven high-risk strains of this family of viruses and may prevent up to 90% of cervical cancers. As a risk of cancer still exists, guidelines recommend continuing regular Pap tests. Other methods of prevention include: having few or no sexual partners and the use of condoms. Cervical cancer screening using the Pap test or acetic acid can identify precancerous changes which when treated can prevent the development of cancer. Treatment of cervical cancer may consist of some combination of surgery, chemotherapy, and radiation therapy. Five-year survival rates in the United States are 68%. Outcomes, however, depend very much on how early the cancer is detected.Worldwide, cervical cancer is both the fourth-most common cause of cancer and the fourth-most common cause of death from cancer in women. In 2012, an estimated 528,000 cases of cervical cancer occurred, with 266,000 deaths. This is about 8% of the total cases and total deaths from cancer. About 70% of cervical cancers occur in developing countries and 90% of the deaths. In low-income countries, it is one of the most common causes of cancer death. In developed countries, the widespread use of cervical screening programs has dramatically reduced rates of cervical cancer. In medical research, the most famous immortalised cell line, known as HeLa, was developed from cervical cancer cells of a woman named Henrietta Lacks.

Cervical cerclage

Cervical cerclage, also known as a cervical stitch, is a treatment for cervical incompetence or insufficiency, when the cervix starts to shorten and open too early during a pregnancy causing either a late miscarriage or preterm birth. Usually the treatment is done in the first or second trimester of pregnancy, for a woman who has had one or more late miscarriages in the past. The word "cerclage" means "hoop" in French, as in the metal hoop encircling a barrel.The treatment consists of a strong suture sewn into and around the cervix early in the pregnancy, usually between weeks 12 to 14, and then removed towards the end of the pregnancy when the greatest risk of miscarriage has passed. The procedure is performed under local anaesthesia, usually by way of a spinal block. It is typically performed on an outpatient basis by an obstetrician-gynecologist.

In women with a prior spontaneous preterm birth and who are pregnant with one baby, and have shortening of the cervical length less than 25 mm, a cerclage prevents a preterm birth and reduces death and illness in the baby. There is no evidence that cerclage is effective in a multiple gestation pregnancy for preventing preterm births and reducing perinatal deaths or neonatal morbidity.

Cervical conization

Cervical conization (CPT codes 57520 (Cold Knife) and 57522 (Loop Excision)) refers to an excision of a cone-shaped sample of tissue from the mucous membrane of the cervix. Conization may be used either for diagnostic purposes as part of a biopsy, or for therapeutic purposes to remove pre-cancerous cells.Types include:

cold knife conization (CKC). Usually outpatient, occasionally inpatient.

loop electrical excision procedure (LEEP). Usually outpatient.Conization of the cervix is a common treatment for dysplasia following abnormal results from a pap smear.

Cervical dilation

Cervical dilation (or cervical dilatation) is the opening of the cervix, the entrance to the uterus, during childbirth, miscarriage, induced abortion, or gynecological surgery. Cervical dilation may occur naturally, or may be induced by surgical or medical means.

Cervical effacement

Cervical effacement (also called cervical ripening) refers to a thinning of the cervix. It is a component of the Bishop score.

It can be expressed as a percentage.Prior to effacement, the cervix is like a long bottleneck, usually about four centimeters in length. Throughout pregnancy, the cervix is tightly closed and protected by a plug of mucus. When the cervix effaces, the mucus plug is loosened and passes out of the vagina. The mucus may be tinged with blood and the passage of the mucus plug is called bloody show (or simply "show"). As effacement takes place, the cervix then shortens, or effaces, pulling up into the uterus and becoming part of the lower uterine wall. Effacement may be measured in percentages, from zero percent (not effaced at all) to 100 percent, which indicates a paper-thin cervix. Effacement is accompanied by cervical dilation.

Cervical intraepithelial neoplasia

Cervical intraepithelial neoplasia (CIN), also known as cervical dysplasia, is the abnormal growth of cells on the surface of the cervix that could potentially lead to cervical cancer. More specifically, CIN refers to the potentially precancerous transformation of cells of the cervix.

CIN most commonly occurs at the squamocolumnar junction of the cervix, a transitional area between the squamous epithelium of the vagina and the columnar epithelium of the endocervix. It can also occur in vaginal walls and vulvar epithelium. CIN is graded on a 1-3 scale, with 3 being the most abnormal (see classification section below).

Human papilloma virus (HPV) infection is necessary for the development of CIN, but not all with this infection develop cervical cancer. A large number of women with HPV infection never develop CIN or cervical cancer. Typically, HPV resolves on its own. However, those with an HPV infection that lasts more than 1 or 2 years have a higher risk of developing a higher grade of CIN.Like other intraepithelial neoplasias, CIN is not cancer and is usually curable. Most cases of CIN either remain stable or are eliminated by the person's immune system without need for intervention. However, a small percentage of cases progress to cervical cancer, typically cervical squamous cell carcinoma (SCC), if left untreated.

Cervical weakness

Cervical weakness, also called cervical incompetence or cervical insufficiency, is a medical condition of pregnancy in which the cervix begins to dilate (widen) and efface (thin) before the pregnancy has reached term. Definitions of cervical weakness vary, but one that is frequently used is the inability of the uterine cervix to retain a pregnancy in the absence of the signs and symptoms of clinical contractions, or labor, or both in the second trimester. Cervical weakness may cause miscarriage or preterm birth during the second and third trimesters. Another sign of cervical weakness is funneling at the internal orifice of the uterus, which is a dilation of the cervical canal at this location.In cases of cervical weakness, dilation and effacement of the cervix may occur without pain or uterine contractions. In a normal pregnancy, dilation and effacement occurs in response to uterine contractions. Cervical weakness becomes a problem when the cervix is pushed to open by the growing pressure in the uterus as pregnancy progresses. If the responses are not halted, rupture of the membranes and birth of a premature baby can result.

According to statistics provided by the Mayo Clinic, cervical weakness is relatively rare in the United States, occurring in only 1–2% of all pregnancies, but it is thought to cause as many as 20—25% of miscarriages in the second trimester.

Colposcopy

Not to be confused with colonoscopy.Colposcopy (Ancient Greek: κόλπος, translit. kolpos, lit. 'hollow, womb, vagina' + skopos "look at") is a medical diagnostic procedure to examine an illuminated, magnified view of the cervix and the tissues of the vagina and vulva. Many premalignant lesions and malignant lesions in these areas have discernible characteristics that can be detected through the examination. It is done using a colposcope, which provides an enlarged view of the areas, allowing the colposcopist to visually distinguish normal from abnormal appearing tissue and take directed biopsies for further pathological examination. The main goal of colposcopy is to prevent cervical cancer by detecting and treating precancerous lesions early. The procedure was developed by the German physician Hans Hinselmann, with help from Eduard Wirths. The development of colposcopy involved experimentation on Jewish inmates from Auschwitz.A specialized colposcope equipped with a camera is used in examining and collecting evidence for victims of rape and sexual assault.

Female reproductive system

The female reproductive system is made up of the internal and external sex organs that function in reproduction of new offspring. In the human the female reproductive system is immature at birth and develops to maturity at puberty to be able to produce gametes, and to carry a foetus to full term. The internal sex organs are the uterus, Fallopian tubes, and ovaries. The uterus or womb accommodates the embryo which develops into the foetus. The uterus also produces vaginal and uterine secretions which help the transit of sperm to the Fallopian tubes. The ovaries produce the ova (egg cells). The external sex organs are also known as the genitals and these are the organs of the vulva including the labia, clitoris, and vaginal opening. The vagina is connected to the uterus at the cervix.At certain intervals, the ovaries release an ovum, which passes through the Fallopian tube into the uterus. If, in this transit, it meets with sperm, a single sperm can enter and merge with the egg, fertilizing it.

Fertilization usually occurs in the Fallopian tubes and marks the beginning of embryogenesis. The zygote will then divide over enough generations of cells to form a blastocyst, which implants itself in the wall of the uterus. This begins the period of gestation and the embryo will continue to develop until full-term. When the foetus has developed enough to survive outside the uterus, the cervix dilates and contractions of the uterus propel the newborn through the birth canal (the vagina).

The corresponding equivalent among males is the male reproductive system.

Glassy cell carcinoma of the cervix

Glassy cell carcinoma of the cervix, also glassy cell carcinoma, is a rare aggressive malignant tumour of the uterine cervix. The tumour gets its name from its microscopic appearance; its cytoplasm has a glass-like appearance.

Neck

The neck is the part of the body, on many vertebrates, that separates the head from the torso. It contains blood vessels and nerves that supply structures in the head to the body. These in humans include part of the esophagus, the larynx, trachea, and thyroid gland, major blood vessels including the carotid arteries and jugular veins, and the top part of the spinal cord.

In anatomy, the neck is also called by its Latin names, cervix or collum, although when used alone, in context, the word cervix more often refers to the uterine cervix, the neck of the uterus. Thus the adjective cervical may refer either to the neck (as in cervical vertebrae or cervical lymph nodes) or to the uterine cervix (as in cervical cap or cervical cancer).

Pap test

The Papanicolaou test (abbreviated as Pap test, also known as Pap smear, cervical smear, cervical screening or smear test) is a method of cervical screening used to detect potentially precancerous and cancerous processes in the cervix (opening of the uterus or womb). Abnormal findings are often followed up by more sensitive diagnostic procedures and if warranted, interventions that aim to prevent progression to cervical cancer. The test was independently invented by Dr. Georgios Papanikolaou and Dr. Aurel Babeș and named after Papanikolaou.

A Pap smear is performed by opening the vaginal canal with a speculum and collecting cells at the outer opening of the cervix at the transformation zone (where the outer squamous cervical cells meet the inner glandular endocervical cells). The collected cells are examined under a microscope to look for abnormalities. The test aims to detect potentially precancerous changes (called cervical intraepithelial neoplasia (CIN) or cervical dysplasia; the squamous intraepithelial lesion system (SIL) is also used to describe abnormalities) caused by human papillomavirus, a sexually transmitted DNA virus. The test remains an effective, widely used method for early detection of precancer and cervical cancer. While the test may also detect infections and abnormalities in the endocervix and endometrium, it is not designed to do so.

In the United States, Pap smear screening is recommended starting around 21 years of age until the age of 65. However, other countries do not recommend pap testing in non-sexually active females. Guidelines on frequency vary from every three to five years. If results are abnormal, and depending on the nature of the abnormality, the test may need to be repeated in six to twelve months. If the abnormality requires closer scrutiny, the patient may be referred for detailed inspection of the cervix by colposcopy. The person may also be referred for HPV DNA testing, which can serve as an adjunct to Pap testing. Additional biomarkers that may be applied as ancillary tests with the Pap test are evolving.

Parametrium

The parametrium is the fibrous and fatty connective tissue that surrounds the uterus. This tissue separates the supravaginal portion of the cervix from the bladder. The parametrium (called cervical stroma in some texts) lies in front of the cervix and extends laterally between the layers of the broad ligaments. It conects the uterus to other tissues in the pelvis. It is different from the perimetrium, which is the outermost layer of the uterus.

The uterine artery and ovarian ligament are located in the parametrium.

An associated form of pelvic inflammatory disease is inflammation of the parametrium known as parametritis.

Pelvic examination

A pelvic examination is the physical examination of the external and internal female pelvic organs. It is called "bimanual exam" when two hands are used and "manual uterine palpation" (palpation meaning an examination by touch). It is frequently used in gynecology. It can also be done under general anesthesia.The examination can be uncomfortable. During the pelvic exam the vaginal wall is assessed for rugae, texture and weak spots. In addition to a thorough pelvic exam, other tests may ordered to further determine the cause of symptoms that are concerning. During the pelvic exam, samples of vaginal fluids may be taken to screen for sexually transmitted infections or other infections.Some clinicians combine a routine pelvic exam along with other preventative procedures like a breast examination and pap smear. The American College of Physicians published guidelines against routine pelvic examination in adult women who are not pregnant and lack symptoms in 2014. One exception being pelvic exams done as part of cervical cancer screening. A pelvic examination can be part of the assessment of sexual assault.

Stenosis of uterine cervix

Cervical stenosis means that the opening in the cervix (the endocervical canal) is more narrow than is typical. In some cases, the endocervical canal may be completely closed. A stenosis is any passage in the body that is more narrow than it should typically be.

Supravaginal portion of cervix

The supravaginal portion of the cervix (also known as the uterine portion of the cervix) is separated in front from the bladder by fibrous tissue (parametrium), which extends also on to its sides and lateralward between the layers of the broad ligaments.

The uterine arteries reach the margins of the cervix in this fibrous tissue, while on either side the ureter runs downward and forward in it at a distance of about 2 cm. from the cervix.

Posteriorly, the supravaginal cervix is covered by peritoneum, which is prolonged below on to the posterior vaginal wall, when it is reflected on to the rectum, forming the recto-uterine pouch.

It is in relation with the rectum, from which it may be separated by coils of small intestine.

Uterus

The uterus (from Latin "uterus", plural uteri) or womb is a major female hormone-responsive secondary sex organ of the reproductive system in humans and most other mammals. In the human, the lower end of the uterus, the cervix, opens into the vagina, while the upper end, the fundus, is connected to the fallopian tubes. It is within the uterus that the fetus develops during gestation. In the human embryo, the uterus develops from the paramesonephric ducts which fuse into the single organ known as a simplex uterus. The uterus has different forms in many other animals and in some it exists as two separate uteri known as a duplex uterus.

In English, the term uterus is used consistently within the medical and related professions, while the Germanic-derived term womb is also commonly used in everyday contexts.

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