View source for Cervix

{{Short description|Lower part of the uterus in the female reproductive system}}
{{Other uses}}
{{Good article}}
{{Infobox anatomy
| Name        = Uterine cervix
| Latin       = cervix uteri
| Image       = Cervix_svg_hariadhi.svg
| Caption     = Human cervix
| Width       =
| Image2      =Scheme_female_reproductive_system-en.svg
| Caption2    = Diagram of the female human reproductive tract 
| Precursor   = [[Paramesonephric duct]]s
| System      =
| Artery      = [[Vaginal artery]] and [[uterine artery]]
| Vein        =
| Nerve       =
| Lymph       =
}}

The '''cervix''' ({{plural form}}: '''cervices''') or '''uterine cervix''' ({{langx|la|cervix uteri}}) is a dynamic fibromuscular [[sexual organ]] of the female [[reproductive system]] that connects the [[vagina]] with the [[uterine cavity]].<ref name=":0">{{Citation |last1=Prendiville |first1=Walter |title=Anatomy of the uterine cervix and the transformation zone |date=2017 |work=Colposcopy and Treatment of Cervical Precancer |url=https://www.ncbi.nlm.nih.gov/books/NBK568392/ |access-date=2024-03-29 |publisher=International Agency for Research on Cancer |language=en |last2=Sankaranarayanan |first2=Rengaswamy}}</ref> The human female cervix has been documented anatomically since at least the time of [[Hippocrates]], over 2,000 years ago. The cervix is approximately {{convert|4|cm|abbr=on}} long with a diameter of approximately {{convert|3|cm|abbr=on}} and tends to be described as a [[cylindrical]] shape, although the front and back walls of the cervix are contiguous.<ref name=":0" /> The size of the cervix changes throughout a female's life cycle. For example, females in the fertile years of their [[reproductive cycle]] tend to have larger cervixes than [[postmenopausal]] females; likewise, females who have produced [[offspring]] have a larger cervix than those who have not.<ref name=":0" />

In relation to the vagina, the part of the cervix that opens into the uterus is called the ''internal os'' while the opening of the cervix into the vagina is called the ''external os''.<ref name=":0" /> Between those extremes is the conduit commonly called the [[cervical canal]]. The lower part of the cervix, known as the vaginal portion of the cervix (or ectocervix), bulges into the top of the vagina.{{Citation needed|date=May 2024}} The endocervix borders the uterus. The cervical conduit has at least two types of [[epithelium]] (lining): the endocervical lining is glandular epithelia that lines the endocervix with a single [[columnar epithelia|layer of column-shaped cells]]; while the ectocervical part of the conduit contains squamous epithelium.<ref name=":0" /> Squamous epithelia line the conduit with [[stratified squamous|multiple layers of cells topped with flat cells]]. These two linings converge at the [[squamocolumnar junction]] (SCJ). This junction changes location dynamically throughout a female's life.<ref name=":0" /> The cervix is the organ that allows epithelia to flow from a female's uterus and out through her vagina at [[menstruation]]. Menstruation releases epithelia from a female’s uterus with every period of her fertile years, unless pregnancy occurs.

Several methods of [[contraception]] aim to prevent fertilization by blocking the conduit, including [[cervical cap]]s and [[Diaphragm (contraceptive)|cervical diaphragm]]s, preventing the passage of sperm through the cervix. Other approaches include methods that observe cervical mucus, such as the [[Creighton Model]] and [[Billings method]]. Cervical mucus's consistency changes during [[menstrual period]]s, which may signal [[ovulation]].

During vaginal [[childbirth]], the cervix must flatten and [[Cervical dilation|dilate]] to allow the [[foetus]] to progress along the birth canal. Midwives and doctors use the extent of [[cervical dilation]] to assist decision-making during childbirth.

Cervical infections with the [[human papillomavirus]] (HPV) can cause changes in the epithelium, which can lead to [[cancer of the cervix]]. [[Exfoliative cervical cytology|Cervical cytology]] tests can detect cervical cancer and its precursors to enable early, successful treatment. Ways to avoid HPV include avoiding heterosexual sex, using penile condoms, and receiving the [[HPV vaccines|HPV vaccination]].<!-- <ref name=NCI2011/> --> HPV vaccines, developed in the early 21st century, reduce the risk of developing cervical cancer by preventing infections from the main cancer-causing strains of HPV.<ref name="NCI2011">{{cite web |date=29 December 2011 |title=Human Papillomavirus (HPV) Vaccines |url=http://www.cancer.gov/cancertopics/factsheet/prevention/HPV-vaccine |access-date=18 June 2014 |website=National Cancer Institute |location=Bethesda, MD}}</ref>

== Structure ==
[[File:Gray1167.svg|right|thumbnail|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 the internal os (internal orifice). The [[cervical canal]] connects the interior of the vagina and the cavity of the body of uterus.|alt=Diagram of the uterus and part of the vagina.]]

The cervix is part of the [[female reproductive system]]. Around {{convert|2–3|cm|in|1}} in length,<ref name=KURMAN1994/> it is the lower, narrower part of the uterus, continuous above with the broader upper part—or body—of the uterus.<ref name=Gray38/> The lower end of the cervix bulges through the anterior wall of the vagina, and is referred to as the vaginal portion of the cervix (or ectocervix), while the rest of the cervix above the vagina is called the [[supravaginal portion of cervix]].<ref name=Gray38/> A central canal, known as the [[Canal of the cervix|cervical canal]], runs along its length and connects the [[cavity of the body of the uterus]] with the lumen of the vagina.<ref name=Gray38/> The openings are known as the [[internal os]] and [[external orifice of the uterus]] (or external os), respectively.<ref name=Gray38/> The mucosa lining the cervical canal is known as the [[endocervix]],<ref name=GRAYS2005>{{cite book | vauthors = Drake RL, Vogl W, Mitchell AW  |others=Illustrations by Richardson P, Tibbitts R |title=Gray's Anatomy for Students |year=2005 |publisher= Elsevier/Churchill Livingstone |location= Philadelphia, PA |isbn= 978-0-8089-2306-0  |pages= 415, 423}}</ref> and the mucosa covering the ectocervix is known as the exocervix.<ref>{{cite book |vauthors = Ovalle WK, Nahirney PC |others=Illustrations by Frank H. Netter, contributing illustrators, Joe Chovan, et al. |title=Netter's Essential Histology |date=2013 |chapter= Female Reproductive System |publisher= Elsevier/Saunders |location= Philadelphia, PA |isbn=978-1-4557-0631-0 |page=416 |edition=2nd }}</ref> 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]].<ref name=Gray38/>

[[File:Cervix uteri, breastfeeding woman after 2 births.jpg|thumbnail|alt=A adult woman's cervix viewed through vagina using a [[Speculum (medical)#Vaginal|vaginal speculum]]|A normal cervix of an adult viewed through vagina using a [[Speculum (medical)#Vaginal|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 [[Mucous membrane|mucosa]].]]

[[File:Cervix birth.png|thumb|Cervix before (left) and after vaginal birth (right)]]

In front of the upper part of the cervix lies the [[Urinary bladder|bladder]], separated from it by cellular connective tissue known as [[parametrium]], which also extends over the sides of the cervix.<ref name=Gray38>{{Cite book | vauthors = Gray H |author-link=Henry Gray | veditors = Williams PL |title=Gray's Anatomy |edition=38th |isbn=0-443-04560-7 |year=1995 |publisher=[[Churchill Livingstone]] |pages=1870–73|title-link=Gray's Anatomy }}</ref> 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]].<ref name=Gray38/> The cervix is more tightly connected to surrounding structures than the rest of the uterus.<ref name="Gardner69">{{cite book | vauthors = Gardner E, Gray DJ, O'Rahilly R |title= Anatomy: A Regional Study of Human Structure |publisher= W.B. Saunders |location= Philadelphia, PA |date=1969 |orig-year=1960 |edition= 3rd |pages= 495–98}}</ref>

The cervical canal varies greatly in length and width between women or throughout a woman's life,<ref name=KURMAN1994 /> and it can measure 8&nbsp;mm (0.3&nbsp;inch) at its widest diameter in [[Premenopause|premenopausal]] adults.<ref name=Blaustein2002/> 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 so that they interlock with each other and close the canal. They are often effaced after pregnancy.<ref name="Gardner69"/><!-- cites previous five sentences -->

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 fornix|vaginal fornices]]. On the rounded part of the ectocervix is a small, depressed [[external orifice of the uterus|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 [[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.<ref name=Blaustein2002>{{cite book|title=Blaustein's Pathology of the Female Genital Tract |edition=5th |page=207 |publisher=Springer |year=2002 |veditors = Kurman RJ }}</ref> On average, the ectocervix is {{convert|3|cm|in|abbr=on}} long and {{convert|2.5|cm|in|sigfig=1|abbr=on}} wide.<ref name=KURMAN1994 />

Blood is supplied to the cervix by the descending branch of the [[uterine artery]]<ref name=DAFTARY2011>{{cite book| vauthors = Daftary SN, Chakravari S |title=Manual of Obstretics, 3/e|year=2011|isbn=978-81-312-2556-1|publisher=Elsevier|pages=1–16}}</ref> and drains into the [[uterine vein]].<ref name=ELLIS2011 /> The [[pelvic splanchnic nerves]], emerging as [[Sacral spinal nerve 2|S2]]–[[Sacral spinal nerve 3|S3]], transmit the sensation of pain from the cervix to the brain.<ref name= GRAYS2005 /> These nerves travel along the [[uterosacral ligament]]s, which pass from the uterus to the anterior [[sacrum]].<ref name="DAFTARY2011"/>

Three channels facilitate [[Lymphatic system|lymphatic drainage]] from the cervix.<ref name=SINGER2005>{{cite book | vauthors = Mould TA, Chow C | chapter = The Vascular, Neural and Lymphatic Anatomy of the Cervix | veditors = Jordan JA, Singer A |title=The Cervix |url=https://archive.org/details/cervixndedition00jord |url-access=limited |date=2005|publisher= Blackwell Publishing |location= Oxford, United Kingdom |pages=[https://archive.org/details/cervixndedition00jord/page/n55 41]–47 |isbn= 9781405131377 |edition=2nd}}</ref> The anterior and lateral cervix drains to [[lymph node|nodes]] along the uterine arteries, travelling along the [[cardinal ligament]]s at the base of the [[broad ligament]] to the [[external iliac lymph nodes]] and ultimately the [[paraaortic lymph node]]s. 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 node]]s.<ref name=KURMAN1994>{{cite book|veditors = Kurman RJ|title=Blaustein's Pathology of the Female Genital Tract|year=1994|publisher=Springer New York|location=New York, NY|isbn=978-1-4757-3889-6|pages=185–201|edition=4th}}</ref><ref name=ELLIS2011>{{cite journal| vauthors = Ellis H |title=Anatomy of the uterus |journal=Anaesthesia & Intensive Care Medicine |year=2011|volume=12|issue=3|pages=99–101|doi=10.1016/j.mpaic.2010.11.005}}</ref><ref name=SINGER2005 /> 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.<ref name=SINGER2005/>

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.<ref name=Weschler>{{cite book | vauthors = Weschler T |title=Taking charge of your fertility: the definitive guide to natural birth control, pregnancy achievement, and reproductive health |year=2006 |publisher=Collins |location=New York, NY |isbn=978-0-06-088190-0 |pages=[https://archive.org/details/takingchargeofy000wesc/page/59 59, 64] |edition=Revised |url=https://archive.org/details/takingchargeofy000wesc/page/59 }}</ref> These changes are also accompanied by changes in cervical mucus,<ref name=CERVIX2006/> described below.

=== Development ===
As a component of the female [[Human reproductive system|reproductive system]], the cervix is derived from the two [[paramesonephric duct]]s (also called Müllerian ducts), which develop around the sixth week of [[human embryogenesis|embryogenesis]]. During development, the outer parts of the two ducts fuse, forming a single [[urogenital]] canal that will become the [[vagina]], cervix and [[uterus]].<ref>{{cite book| vauthors = Schoenwolf GC, Bleyl SB, Brauer PR, Francis-West PH |title=Larsen's human embryology|year=2009|publisher=Churchill Livingstone/Elsevier|location=Philadelphia, PA |isbn=978-0-443-06811-9|chapter="Development of the Urogenital system"|edition=4th}}</ref> 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 [[fetus|fetal life]], twice as large during childhood, and decreasing to its adult size, smaller than the uterus, after puberty.<ref name=ELLIS2011 /> 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.<ref name=Cervix2006>{{cite book|title=The Cervix | veditors = Jordan J, Singer A, Jones H, Shafi M |chapter=Morphogenesis and Differentiation of the cervicovaginal epithelium | vauthors = McLean JM |url=https://books.google.com/books?id=Gbp2uRBLE9cC |isbn=978-1-4051-3137-7 |date=November 2006 |publisher=Wiley-Blackwell|edition=2nd }}</ref>{{rp|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.<ref name=Reich2014>{{cite journal | vauthors = Reich O, Fritsch H | title = The developmental origin of cervical and vaginal epithelium and their clinical consequences: a systematic review | journal = Journal of Lower Genital Tract Disease | volume = 18 | issue = 4 | pages = 358–360 | date = October 2014 | pmid = 24977630 | doi = 10.1097/LGT.0000000000000023 | s2cid = 3060493 }}</ref>

=== Histology ===
{{Anchor|Transformation zone}}
{{Multiple image
| total_width       = 270
| image1            = Histology of transformation zone mucosa.jpg
| caption1          = Transformation zone mucosa, when the squamocolumnar junction has a gradual transition. It consists of a mix of stratified squamous epithelium and mucinous glands. [[H&E stain]].
| image2            = Histology of endocervix.jpg
| caption2          = Histology of endocervix, with mucinous columnar epithelium and mucinous glands. H&E stain.
}}
[[File:Nulliparous cervix with ectropion.jpg|thumb|upright=0.75|A nulliparous woman's ectocervix showing [[cervical ectropion]], visible as the darker red mucosa surrounding the cervical os. Viewed on speculum exam.]]
The endocervical mucosa is about {{convert|3|mm|abbr=on}} thick and lined with a single layer of columnar mucous cells. It contains numerous tubular mucous glands, which empty viscous alkaline mucus into the lumen.<ref name=Gray38/> In contrast, the ectocervix is covered with nonkeratinized stratified squamous epithelium,<ref name=Gray38/> which resembles the squamous epithelium lining the vagina.<ref name=0&G-7th/>{{rp|41}} The junction between these two types of epithelia is called the squamocolumnar junction.<ref name=0&G-7th>{{cite book |title= Obstetrics and Gynecology |edition=7th |url= https://books.google.com/books?id=dD-emqhOXa0C | vauthors = Beckmann CR, Herbert W, Laube D, Ling F, Smith R |date=March 2013 |pages=408–11 |publisher=Lippincott Williams & Wilkins |isbn= 9781451144314}}</ref>{{rp|408–11}} Underlying both types of epithelium is a tough layer of [[collagen]].<ref name=WHEATERS2006>{{cite book| vauthors = Young B |title=Wheater's functional histology: a text and colour atlas|url=https://archive.org/details/wheatersfunction00youn|url-access=limited|year=2006|publisher=Churchill Livingstone/Elsevier |location=Edinburgh, United Kingdom |isbn=978-0-443-06850-8 |edition=5th|page=[https://archive.org/details/wheatersfunction00youn/page/n851 376]}}</ref> The mucosa of the endocervix is not shed during menstruation. The cervix has more fibrous tissue, including collagen and [[elastin]], than the rest of the uterus.<ref name=Gray38/><!-- cites 2 previous sentences -->
<gallery mode="packed" heights="110">
File:Cervix Normal Squamocolumnar Junction (565238127).jpg|The squamocolumnar junction of the cervix, with abrupt transition: 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.
File:Transformation zone types.png|Transformation zone types:<ref>International Federation for Cervical Pathology and Colposcopy (IFCPC) classification. References:<br>-{{cite web|url=https://www.rcpa.edu.au/Library/Practising-Pathology/Structured-Pathology-Reporting-of-Cancer/Docs/Transformation_zone|title=Transformation zone (TZ) and cervical excision types|website=[[Royal College of Pathologists of Australasia]]}}<br>- {{cite journal | vauthors = Jordan J, Arbyn M, Martin-Hirsch P, Schenck U, Baldauf JJ, Da Silva D, Anttila A, Nieminen P, Prendiville W | display-authors = 6 | title = European guidelines for quality assurance in cervical cancer screening: recommendations for clinical management of abnormal cervical cytology, part 1 | journal = Cytopathology | volume = 19 | issue = 6 | pages = 342–354 | date = December 2008 | pmid = 19040546 | doi = 10.1111/j.1365-2303.2008.00623.x | s2cid = 16462929 | doi-access = free }}</ref><br>Type 1: Completely ectocervical (common under hormonal influence).<br>Type 2: Endocervical component but fully visible (common before puberty).<br>Type 3: Endocervical component, not fully visible (common after menopause).
</gallery>
In [[preadolescence|prepubertal]] girls, the functional squamocolumnar junction is just within the cervical canal.<ref name=0&G-7th/>{{rp|411}} Upon entering puberty, due to hormonal influence, and during pregnancy, the columnar epithelium extends outward over the ectocervix as the cervix everts.<ref name=Cervix2006/>{{rp|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.<ref name=Cervix2006/>{{rp|106}}<ref name=0&G-7th/>{{rp|411}} The exposed columnar epithelium can undergo physiological [[metaplasia]] and change to tougher metaplastic squamous epithelium in days or weeks,<ref name=0&G-7th/>{{rp|25}} which is very similar to the original squamous epithelium when mature.<ref name=0&G-7th/>{{rp|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.<ref name=0&G-7th/>{{rp|411}} Histologically, the transformation zone is generally defined as surface squamous epithelium with surface columnar epithelium or stromal glands/crypts, or both.<ref name="pmid15917428">{{cite journal | vauthors = Mukonoweshuro P, Oriowolo A, Smith M | title = Audit of the histological definition of cervical transformation zone | journal = Journal of Clinical Pathology | volume = 58 | issue = 6 | pages = 671 | date = June 2005 | pmid = 15917428 | pmc = 1770692 }}</ref>

After menopause, the uterine structures involute, and the functional squamocolumnar junction moves into the cervical canal.<ref name=0&G-7th/>{{rp|41}}

[[Nabothian cyst]]s (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.<ref name=0&G-7th/>{{rp|410–411}} A buildup of mucus in the glands forms Nabothian cysts, usually less than about {{convert|abbr=on|5|mm}} in diameter,<ref name=Gray38/> which are considered physiological rather than pathological.<ref name=0&G-7th/>{{rp|411}} Both gland openings and Nabothian cysts are helpful to identify the transformation zone.<ref name=Cervix2006/>{{rp|106}}

== Function ==
=== Fertility ===
The cervical canal is a pathway through which sperm enter the uterus after being induced by [[estradiol]] after [[penile-vaginal intercourse]],<ref name=GUYTONHALL2005>{{cite book| vauthors = Guyton AC, Hall JE |title=Textbook of Medical Physiology|date=2005|publisher=W.B. Saunders|location=Philadelphia, PA|isbn=978-0-7216-0240-0|page=1027|edition=11th}}</ref> and some forms of [[artificial insemination]].<ref>{{cite web|title=Demystifying IUI, ICI, IVI and IVF |date=4 January 2014 |url=https://www.seattlespermbank.com/demystifying-iui-ici-ivi-and-ivf/ |publisher=Seattle Sperm Bank |access-date=9 November 2014}}</ref> 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.<ref name=BRANNIGAN2008>{{cite journal| vauthors = Brannigan RE, Lipshultz LI |title=Sperm Transport and Capacitation|year=2008|journal=The Global Library of Women's Medicine|doi=10.3843/GLOWM.10316|url=https://www.glowm.com/section_view/heading/Sperm%20Transport%20and%20Capacitation/item/315|url-access=subscription}}</ref> A theory states the cervical and uterine contractions during [[orgasm]] draw semen into the uterus.<ref name=GUYTONHALL2005 /> 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.<ref>{{cite journal| vauthors = Levin RJ |title=The human female orgasm: a critical evaluation of its proposed reproductive functions|journal=Sexual and Relationship Therapy|date=November 2011|volume=26|issue=4|pages=301–14|doi=10.1080/14681994.2011.649692|s2cid=143550619}}</ref><ref>{{cite journal | vauthors = Borrow AP, Cameron NM | title = The role of oxytocin in mating and pregnancy | journal = Hormones and Behavior | volume = 61 | issue = 3 | pages = 266–276 | date = March 2012 | pmid = 22107910 | doi = 10.1016/j.yhbeh.2011.11.001 | s2cid = 45783934 }}</ref>

Some methods of [[fertility awareness]], such as the [[Creighton Model FertilityCare System|Creighton model]] and the [[Billings ovulation method|Billings method]] involve estimating a woman's periods of fertility and infertility by observing physiological changes in her body.<ref>{{Cite journal |last1=Thijssen |first1=A. |last2=Meier |first2=A. |last3=Panis |first3=K. |last4=Ombelet |first4=W. |date=2014 |title='Fertility Awareness-Based Methods' and subfertility: a systematic review |journal=Facts, Views & Vision in ObGyn |volume=6 |issue=3 |pages=113–123 |issn=2032-0418 |pmc=4216977 |pmid=25374654}}</ref> 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 [[Fern test|ferning]].<ref name="Weschler"/>

=== Cervical mucus ===
Several hundred mucus-secreting crypts<ref>{{Citation |last=Stolnicu |first=Simona |title=Anatomy, Histology, Cytology, and Colposcopy of the Cervix |date=2021 |work=Atlas of Diagnostic Pathology of the Cervix |pages=1–23 |editor-last=Soslow |editor-first=Robert A. |url=http://link.springer.com/10.1007/978-3-030-49954-9_1 |access-date=2025-11-16 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-49954-9_1 |isbn=978-3-030-49953-2 |last2=Goldfrank |first2=Deborah |editor2-last=Park |editor2-first=Kay J. |editor3-last=Stolnicu |editor3-first=Simona}}</ref> in the endocervix produce 20–60&nbsp;mg of cervical [[mucus]] a day, increasing to 600&nbsp;mg around the time of ovulation. The viscosity and water content vary during the [[menstrual cycle]]; cervical mucus is composed of around 93% water, reaching 98% at midcycle.  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]].<ref name=CERVIX2006>{{cite book| vauthors = Sharif K, Olufowobi O |title=The Cervix|url=https://archive.org/details/cervixndedition00jord|url-access=limited| veditors = Jordan J, Singer A, Jones H, Shafi M |publisher=Blackwell Publishing|location=Malden, MA | date=2006|edition=2nd|pages=[https://archive.org/details/cervixndedition00jord/page/n171 157]–68 |chapter=The structure chemistry and physics of human cervical mucus|isbn=978-1-4051-3137-7}}</ref><!-- cites four previous sentences --> Its consistency is determined by the influence of the hormones estrogen and progesterone. In the follicular phase of the menstrual cycle, estrogen dominates and cervical mucus gradually becomes thinner, hitting its lowest viscosity at ovulation.<ref>{{Cite journal |last=Han |first=Leo |last2=Roberts |first2=Mackenzie |last3=Luo |first3=Addie |last4=Wei |first4=Shuhao |last5=Slayden |first5=Ov D |last6=Macdonald |first6=Kelvin D |date=2022-09-12 |title=Functional evaluation of the cystic fibrosis transmembrane conductance regulator in the endocervix |url=https://academic.oup.com/biolreprod/article/107/3/732/6582490 |journal=Biology of Reproduction |language=en |volume=107 |issue=3 |pages=732–740 |doi=10.1093/biolre/ioac090 |issn=0006-3363 |pmc=9476216 |pmid=35532160}}</ref><ref>{{Cite journal |last=Moghissi |first=Kamran S. |date=1966-09-01 |title=Cyclic Changes of Cervical Mucus in Normal and Progestin-Treated Women |url=https://www.sciencedirect.com/science/article/pii/S001502821636068X |journal=Fertility and Sterility |volume=17 |issue=5 |pages=663–675 |doi=10.1016/S0015-0282(16)36068-X |issn=0015-0282}}</ref> 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.<ref name=BRANNIGAN2008 /> 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.<ref name = Weschler/> The mucus has a stretchy character described as ''Spinnbarkeit'' most prominent around ovulation.<ref name="pmid15775876">{{cite journal | vauthors = Anderson M, Karasz A, Friedland S | title = Are vaginal symptoms ever normal? a review of the literature | journal = MedGenMed | volume = 6 | issue = 4 | pages = 49 | date = November 2004 | pmid = 15775876 | pmc = 1480553 }}</ref>

At other times in the cycle, the mucus is thick and more acidic due to the effects of progesterone.<ref name=BRANNIGAN2008 /> This "infertile" mucus acts as a barrier to keep sperm from entering the uterus.<ref>{{cite book | vauthors = Westinore A, Billings E |title=The Billings Method: Controlling Fertility Without Drugs or Devices |publisher=Life Cycle Books |location=Toronto, ON |year=1998 |page=37 |isbn=0-919225-17-9}}</ref> Women taking an [[oral contraceptive pill]] also have thick mucus from the effects of progesterone.<ref name=BRANNIGAN2008 /> Thick mucus also prevents [[pathogen]]s from interfering with a nascent pregnancy.<ref name="pmid7431318">{{cite journal | vauthors = Wagner G, Levin RJ | title = Electrolytes in vaginal fluid during the menstrual cycle of coitally active and inactive women | journal = Journal of Reproduction and Fertility | volume = 60 | issue = 1 | pages = 17–27 | date = September 1980 | pmid = 7431318 | doi = 10.1530/jrf.0.0600017 | doi-access = free }}</ref>

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 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.<ref>{{cite journal | vauthors = Becher N, Adams Waldorf K, Hein M, Uldbjerg N | title = The cervical mucus plug: structured review of the literature | journal = Acta Obstetricia et Gynecologica Scandinavica | volume = 88 | issue = 5 | pages = 502–513 | date = May 2009 | pmid = 19330570 | doi = 10.1080/00016340902852898 | s2cid = 23738950 }}</ref> It is visible as a blood-tinged mucous discharge.<ref>{{cite book| vauthors =  Lowdermilk DL, Perry SE |title=Maternity Nursing|year=2006|publisher=Elsevier Mosby|location=Edinburgh, United Kingdom|isbn=978-0-323-03366-4|page=[https://archive.org/details/maternitynursing00deit/page/394 394]|edition=7th|url=https://archive.org/details/maternitynursing00deit/page/394}}</ref>

=== Childbirth ===
[[File:Positive Feedback- Childbirth (1).svg|thumb|upright=0.6|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 [[Presentation (obstetrics)|presenting part]], usually [[cephalic presentation|the head]], rests on and is supported by the cervix.<ref name=WILLIAMS2005/> As labour progresses, the cervix becomes softer and shorter, begins to dilate, and withdraws to face the anterior of the body.<ref name=GOLDENBERG2008 /> The support the cervix provides to the fetal head starts to give way when the uterus begins its [[Uterine contraction|contractions]]. During childbirth, the [[Cervical dilation|cervix must dilate]] to a diameter of more than {{convert|abbr=on|10|cm|in|1}} 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 [[cervical effacement|effacement]].<ref name=WILLIAMS2005 />

Along with other factors, midwives and doctors use the extent of [[cervical dilation]] to assist decision-making during [[Stages of labor|childbirth]].<ref name=NICE-labour>NICE (2007). Section 1.6, ''Normal labour: first stage''</ref><ref name="NICE 2007">NICE (2007). Section 1.7, ''Normal labour: second stage''</ref> Generally, the active first stage of labour, when the uterine contractions become strong and regular,<ref name=NICE-labour/> begins when the cervical dilation is more than {{convert|3–5|cm|in|abbr=on}}.<ref>{{cite news|author=ACOG|title=Obstetric Data Definitions Issues and Rationale for Change|url=http://www.acog.org/About_ACOG/ACOG_Departments/Patient_Safety_and_Quality_Improvement/~/media/Departments/Patient%20Safety%20and%20Quality%20Improvement/201213IssuesandRationale-Labor.pdf|year=2012|work=Revitalize|access-date=4 November 2014|url-status=dead|archive-url=https://web.archive.org/web/20131106064308/http://www.acog.org/About_ACOG/ACOG_Departments/Patient_Safety_and_Quality_Improvement/~/media/Departments/Patient%20Safety%20and%20Quality%20Improvement/201213IssuesandRationale-Labor.pdf|archive-date=6 November 2013|author-link=American Congress of Obstetricians and Gynecologists}}</ref><ref>{{cite journal | vauthors = Su M, Hannah WJ, Willan A, Ross S, Hannah ME | title = Planned caesarean section decreases the risk of adverse perinatal outcome due to both labour and delivery complications in the Term Breech Trial | journal = BJOG | volume = 111 | issue = 10 | pages = 1065–1074 | date = October 2004 | pmid = 15383108 | doi = 10.1111/j.1471-0528.2004.00266.x | s2cid = 10086313 | doi-access =  }}</ref> The second phase of labor begins when the cervix has dilated to {{convert|10|cm|in|sigfig=1|abbr=on}}, which is regarded as its fullest dilation,<ref name=WILLIAMS2005>{{cite book| vauthors = Cunningham F, Leveno K, Bloom S, Hauth J, Gilstrap L, Wenstrom K |title=Williams obstetrics |year=2005|publisher=McGraw-Hill Professional|location=New York; Toronto |isbn=0-07-141315-4|edition=22nd|pages=157–60, 537–39}}</ref> and is when active pushing and contractions push the baby along the [[birth canal]] leading to the birth of the baby.<ref name="NICE 2007"/> [[parity (biology)|The number of past vaginal deliveries]] is a strong factor in influencing how rapidly the cervix can dilate in labour.<ref name="WILLIAMS2005" /> 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]], [[Labor induction|induction]], or [[Caesarean section]] should be used in childbirth.<ref name="WILLIAMS2005" />

[[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]].<ref name=GOLDENBERG2008>{{cite journal | vauthors = Goldenberg RL, Culhane JF, Iams JD, Romero R | title = Epidemiology and causes of preterm birth | journal = Lancet | volume = 371 | issue = 9606 | pages = 75–84 | date = January 2008 | pmid = 18177778 | pmc = 7134569 | doi = 10.1016/S0140-6736(08)60074-4 }}</ref>

=== Contraception ===
Several methods of [[contraception]] involve the cervix. [[Diaphragm (contraceptive)|Cervical diaphragm]]s are reusable, firm-rimmed plastic devices inserted by a woman before 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 cap]]s are a similar method, although they are smaller and adhere to the cervix by suction. Diaphragms and caps are often used in conjunction with [[spermicide]]s.<ref>{{cite book | author = NSW Family Planning|title=Contraception: healthy choices: a contraceptive clinic in a book|year=2009|publisher=UNSW Press|location=Sydney, New South Wales|isbn=978-1-74223-136-5|pages=27–37|edition=2nd}}</ref> In one year, 12% of women using the diaphragm will undergo an unintended pregnancy, and with optimal use this falls to 6%.<ref>{{cite journal | vauthors = Trussell J | title = Contraceptive failure in the United States | journal = Contraception | volume = 83 | issue = 5 | pages = 397–404 | date = May 2011 | pmid = 21477680 | pmc = 3638209 | doi = 10.1016/j.contraception.2011.01.021 }}</ref> Efficacy rates are lower for the cap, with 18% of women undergoing an unintended pregnancy, and 10–13% with optimal use.<ref>{{cite journal | vauthors = Trussell J, Strickler J, Vaughan B | title = Contraceptive efficacy of the diaphragm, the sponge and the cervical cap | journal = Family Planning Perspectives | volume = 25 | issue = 3 | pages = 100–5, 135 | date = May–Jun 1993 | pmid = 8354373 | doi = 10.2307/2136156 | jstor = 2136156 }}</ref> Most types of [[progestogen-only pill]]s are effective as a contraceptive because they thicken cervical mucus, making it difficult for sperm to pass along the cervical canal.<ref name=FPA-POP>{{cite book|title=Your Guide to the progesterone-one pill |url=http://www.fpa.org.uk/sites/default/files/progestogen-only-pill-your-guide.pdf |archive-url=https://web.archive.org/web/20140327100545/http://www.fpa.org.uk/sites/default/files/progestogen-only-pill-your-guide.pdf |archive-date=2014-03-27 |url-status=live |publisher=Family Planning Association (UK)|access-date=9 November 2014 |pages=3–4 |isbn=978-1-908249-53-1}}</ref> In addition, they may also sometimes prevent ovulation.<ref name=FPA-POP/> In contrast, contraceptive pills that contain both oestrogen and progesterone, the [[combined oral contraceptive pill]]s, work mainly by preventing [[ovulation]].<ref name=FPA-COC/> They also thicken cervical mucus and thin the lining of the uterus, enhancing their effectiveness.<ref name=FPA-COC>{{cite book|title=Your Guide to the combined pill |url=http://www.fpa.org.uk/sites/default/files/the-combined-pill-your-guide.pdf |archive-url=https://web.archive.org/web/20131102201353/http://www.fpa.org.uk/sites/default/files/the-combined-pill-your-guide.pdf |archive-date=2013-11-02 |url-status=live |publisher=Family Planning Association (UK) |access-date=9 November 2014 |page=4 |date =January 2014 |isbn=978-1-908249-50-0}}</ref>

==Clinical significance==
===Cancer===
{{Main|Cervical 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.{{Update after|2021|3|17}}<ref name=ARBYN2011>{{cite journal | vauthors = Arbyn M, Castellsagué X, de Sanjosé S, Bruni L, Saraiya M, Bray F, Ferlay J | title = Worldwide burden of cervical cancer in 2008 | journal = Annals of Oncology | volume = 22 | issue = 12 | pages = 2675–2686 | date = December 2011 | pmid = 21471563 | doi = 10.1093/annonc/mdr015 | doi-access = free }}</ref> It is a leading cause of cancer-related death in poor countries, where delayed diagnosis leading to poor outcomes is common.<ref name="who fact sheet">{{cite web |author=World Health Organization |date=February 2014 |title=Fact sheet No. 297: Cancer |url=https://www.who.int/mediacentre/factsheets/fs297/en/index.html |access-date=23 July 2014|author-link=World Health Organization }}</ref> 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 occurs there.<ref name="Vaccarella13">{{cite journal | vauthors = Vaccarella S, Lortet-Tieulent J, Plummer M, Franceschi S, Bray F | title = Worldwide trends in cervical cancer incidence: impact of screening against changes in disease risk factors | journal = European Journal of Cancer | volume = 49 | issue = 15 | pages = 3262–3273 | date = October 2013 | pmid = 23751569 | doi = 10.1016/j.ejca.2013.04.024 }}</ref>

Cervical cancer nearly always involves human papillomavirus (HPV) infection.<ref name=WAHL2007>{{cite book| vauthors = Wahl CE |title=Hardcore pathology|date=2007|publisher=Lippincott Williams & Wilkins|location=Philadelphia, PA |isbn=9781405104982|page=72|url=https://books.google.com/books?id=JZtr6cmJhvgC&q=transformation+zone+vaginal+pH&pg=PA72}}</ref><ref name=ROBBINS2007/> 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.<ref name=LOWE2005>{{cite book| vauthors = Lowe A, Stevens JS |title=Human histology|year=2005|publisher=Elsevier Mosby|location=Philadelphia, PA; Toronto, ON|isbn=0-323-03663-5|edition=3rd|pages=350–51}}</ref> [[HPV vaccines]], such as [[Gardasil]] and [[Cervarix]], reduce the incidence of cervical cancer, by inoculating against the viral strains involved in cancer development.<ref name=HARRISONS2010B>{{cite book| veditors = Fauci AS, Braunwald E, Kasper DL, Hauser SL, Longo DL, Jameson JL, Loscalzo J |title=Harrison's Principles of Internal Medicine|url=https://archive.org/details/harrisonsprincip00asfa |url-access=limited |date=2008|publisher=McGraw-Hill Medical|location=New York [etc.]|isbn=978-0-07-147692-8|pages=[https://archive.org/details/harrisonsprincip00asfa/page/n646 608]–09|edition=17th}}</ref>

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 [[epithelium|epithelial]] cells are scraped from the surface of the cervix and [[cytopathology|examined under a microscope]].<ref name=HARRISONS2010B/> The [[Colposcopy|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.<ref name=GASPARINI2009 /> A [[loop electrical excision procedure|LEEP procedure]] using a heated loop of [[platinum]] to excise a patch of cervical tissue was developed by [[Aurel Babes]] in 1927.<ref>{{cite journal | vauthors = Diamantis A, Magiorkinis E, Androutsos G | title = Different strokes: Pap-test and Babes method are not one and the same | journal = Diagnostic Cytopathology | volume = 38 | issue = 11 | pages = 857–859 | date = November 2010 | pmid = 20973044 | doi = 10.1002/dc.21347 | s2cid = 823546 }}</ref> In some parts of the developed world, including the UK, the Pap test has been superseded with [[liquid-based cytology]].<ref>{{cite book |url= https://books.google.com/books?id=eqC-0qjzl_AC&q=nice+lbc&pg=PA614 |title= Diagnostic Cytopathology | veditors = Gray W, Kocjan G |year=2010 |page=613 |publisher= Churchill Livingstone|isbn= 9780702048951 }}</ref>

An inexpensive, cost-effective and practical alternative in poorer countries is [[Cervical screening#Visual inspection to detect pre-cancer or cancer|visual inspection with acetic acid]] (VIA).<ref name="who fact sheet"/> 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.<ref name=sherris>{{cite journal | vauthors = Sherris J, Wittet S, Kleine A, Sellors J, Luciani S, Sankaranarayanan R, Barone MA | title = Evidence-based, alternative cervical cancer screening approaches in low-resource settings | journal = International Perspectives on Sexual and Reproductive Health | volume = 35 | issue = 3 | pages = 147–154 | date = September 2009 | pmid = 19805020 | doi = 10.1363/3514709 | doi-access = free }}</ref>

A result of [[dysplasia]] is usually further investigated, such as by taking a [[cone biopsy]], which may also remove the cancerous lesion.<ref name=HARRISONS2010B/> [[Cervical intraepithelial neoplasia]] is a possible result of the biopsy and represents dysplastic changes that may eventually progress to invasive cancer.<ref name=NEJM1996>{{cite journal | vauthors = Cannistra SA, Niloff JM | title = Cancer of the uterine cervix | journal = The New England Journal of Medicine | volume = 334 | issue = 16 | pages = 1030–1038 | date = April 1996 | pmid = 8598842 | doi = 10.1056/NEJM199604183341606 }}</ref> 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.<ref name=DAVIDSONS2010>{{cite book | veditors = Colledge NR, Walker BR, Ralston SH |others= Illustrated by Britton R |title= Davidson's Principles and Practice of Medicine |url= https://archive.org/details/davidsonsprincip00frcp |url-access= limited |year=2010 |publisher= Churchill Livingstone/Elsevier |location= Edinburgh |isbn=978-0-7020-3084-0 |edition= 21st |page=[https://archive.org/details/davidsonsprincip00frcp/page/n292 276] }}</ref>

===Inflammation===
{{Main|Cervicitis}}

Inflammation of the cervix is referred to as [[cervicitis]]. This inflammation may be of the endocervix or ectocervix.<ref name=STAMM2013>{{cite book | vauthors = Stamm W |title=The Practitioner's Handbook for the Management of Sexually Transmitted Diseases |date=2013 |publisher= Seattle STD/HIV Prevention Training Center |pages= Chapter 7: Cervicitis |url= http://depts.washington.edu/handbook/syndromesFemale/ch7_cervicitis.html|archive-url= https://web.archive.org/web/20130622033953/http://depts.washington.edu/handbook/syndromesFemale/ch7_cervicitis.html |url-status= dead |archive-date= 2013-06-22  }}</ref> When associated with the endocervix, it is associated with a mucous vaginal discharge and [[sexually transmitted infection]]s such as [[chlamydia infection|chlamydia]] and [[gonorrhoea]].<ref name=HARRISONS2010 /> As many as half of pregnant women having a gonorrheal infection of the cervix are asymptomatic.<ref name=Kenner2014>{{cite book | vauthors = Kenner C |title= Comprehensive neonatal nursing care | publisher= Springer Publishing Company, LLC |place= New York |edition=5th |year= 2014 | isbn= 9780826109750}} Access provided by the University of Pittsburgh.</ref> Other causes include overgrowth of the [[commensal flora]] of the vagina.<ref name=ROBBINS2007>{{cite book | vauthors = Mitchell RS, Kumar V, Robbins SL, Abbas AK, Fausto N |title= Robbins basic pathology |publisher= Saunders/Elsevier |year=2007 |edition=8th | pages=716–21 |isbn=978-1-4160-2973-1 }}</ref> 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 (medical)|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.<ref name=HARRISONS2010>{{cite book | veditors = Fauci AS, Braunwald E, Kasper DL, Hauser SL, Longo DL, Jameson JL, Loscalzo J  |title= Harrison's Principles of Internal Medicine |url= https://archive.org/details/harrisonsprincip00asfa |url-access= limited |date=2008 |publisher= McGraw-Hill Medical |location= New York [etc.] |isbn= 978-0-07-147692-8 |pages=[https://archive.org/details/harrisonsprincip00asfa/page/n866 828]–29 |edition=17th }}</ref>

===Anatomical abnormalities===
[[Stenosis of uterine cervix|Cervical stenosis]] is an abnormally narrow cervical canal, typically associated with trauma caused by removal of tissue for investigation or treatment of cancer, or [[cervical cancer]] itself.<ref name=ROBBINS2007 /><ref>{{cite journal | vauthors = Valle RF, Sankpal R, Marlow JL, Cohen L |title= Cervical Stenosis: A Challenging Clinical Entity |journal= Journal of Gynecologic Surgery |volume=18 |issue=4 |pages=129–43 |doi= 10.1089/104240602762555939 |year=2002 }}</ref> [[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 adenocarcinoma]]s; cervical ridges and hoods; and development of a cockscomb cervix appearance,<ref name="CaseyLong2011"/> which is the condition wherein, as the name suggests, the cervix of the [[uterus]] is shaped like a [[comb (anatomy)|cockscomb]]. About one-third of women born to [[diethylstilbestrol]]-treated mothers (i.e., in-utero exposure) develop a cockscomb cervix.<ref name="CaseyLong2011">{{cite journal | vauthors = Casey PM, Long ME, Marnach ML | title = Abnormal cervical appearance: what to do, when to worry? | journal = Mayo Clinic Proceedings | volume = 86 | issue = 2 | pages = 147–50; quiz 151 | date = February 2011 | pmid = 21270291 | pmc = 3031439 | doi = 10.4065/mcp.2010.0512 }}</ref>

Enlarged folds or ridges of cervical [[Stroma (animal tissue)|stroma]] (fibrous tissues) and [[epithelium]] constitute a cockscomb cervix.<ref name=NCI>{{cite web|title=Diethylstilbestrol (DES) Cervix|url=https://visualsonline.cancer.gov/details.cfm?imageid=7590|website=National Cancer Institute Visuals|publisher=National Cancer Institute|access-date=14 May 2015}}</ref> Similarly, cockscomb [[polyp (medicine)|polyp]]s 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.<ref name="Wingfield1991">{{cite journal | vauthors = Wingfield M | title = The daughters of stilboestrol | journal = BMJ | volume = 302 | issue = 6790 | pages = 1414–1415 | date = June 1991 | pmid = 2070103 | pmc = 1670127 | doi = 10.1136/bmj.302.6790.1414 }}</ref><ref name="Mittendorf1995">{{cite journal | vauthors = Mittendorf R | title = Teratogen update: carcinogenesis and teratogenesis associated with exposure to diethylstilbestrol (DES) in utero | journal = Teratology | volume = 51 | issue = 6 | pages = 435–445 | date = June 1995 | pmid = 7502243 | doi = 10.1002/tera.1420510609 }}</ref><ref name="HerbstPoskanzer1975">{{cite journal | vauthors = Herbst AL, Poskanzer DC, Robboy SJ, Friedlander L, Scully RE | title = Prenatal exposure to stilbestrol. A prospective comparison of exposed female offspring with unexposed controls | journal = The New England Journal of Medicine | volume = 292 | issue = 7 | pages = 334–339 | date = February 1975 | pmid = 1117962 | doi = 10.1056/NEJM197502132920704 }}</ref>

[[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.<ref>{{cite journal | vauthors = Fujimoto VY, Miller JH, Klein NA, Soules MR | title = Congenital cervical atresia: report of seven cases and review of the literature | journal = American Journal of Obstetrics and Gynecology | volume = 177 | issue = 6 | pages = 1419–1425 | date = December 1997 | pmid = 9423745 | doi = 10.1016/S0002-9378(97)70085-1 }}</ref> 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]].<ref>{{cite journal | vauthors = Patton PE, Novy MJ, Lee DM, Hickok LR | title = The diagnosis and reproductive outcome after surgical treatment of the complete septate uterus, duplicated cervix and vaginal septum | journal = American Journal of Obstetrics and Gynecology | volume = 190 | issue = 6 | pages = 1669–75; discussion p.1675–78 | date = June 2004 | pmid = 15284765 | doi = 10.1016/j.ajog.2004.02.046 }}</ref>

[[Cervical polyp]]s, which are benign overgrowths of endocervical tissue, if present, may cause bleeding, or a benign overgrowth may be present in the cervical canal.<ref name=ROBBINS2007 /> [[Cervical ectropion]] refers to the horizontal overgrowth of the endocervical columnar lining in a one-cell-thick layer over the ectocervix.<ref name=HARRISONS2010 />

==Animals==
Female marsupials have [[Marsupial#Female reproductive system|paired uteri and cervices]].<ref name="Tyndale-Biscoe2005">{{cite book| vauthors = Tyndale-Biscoe CH |title=Life of Marsupials|url=https://books.google.com/books?id=KqtlPZJ9y8EC|year=2005|publisher=Csiro Publishing|isbn=978-0-643-06257-3}}</ref><ref name="Tyndale-BiscoeRenfree1987">{{cite book| vauthors = Tyndale-Biscoe H, Renfree M |title=Reproductive Physiology of Marsupials|url=https://books.google.com/books?id=HpjovN0vXW4C|date=30 January 1987|publisher=Cambridge University Press|isbn=978-0-521-33792-2}}</ref> Most [[eutheria]]n (placental) mammal species have a single cervix and a single, bipartite or bicornuate uterus. [[Lagomorph]]s, [[rodents]], [[aardvarks]], and [[hyraxes]] have a duplex uterus and two cervices.<ref name=feldhamer>{{cite book | vauthors = Feldhamer GA, Drickamer LC, Vessey SH, Merritt JF, Krajewski C |title= Mammalogy: Adaptation, Diversity, Ecology |publisher=JHU Press |location= Baltimore, MD |date=2007 |page=198 |isbn=9780801886959 |url= https://books.google.com/books?id=udCnKce9hfoC }}</ref><!-- cites previous 3 sentences --> 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.<ref name=novacek>{{cite journal | vauthors = Novacek MJ, Wyss AR | title = Higher-Level Relationships of the Recent Eutherian Orders: Morphological Evidence | journal = Cladistics | volume = 2 | issue = 4 | pages = 257–287 | date = September 1986 | pmid = 34949071 | doi = 10.1111/j.1096-0031.1986.tb00463.x | s2cid = 85140444 }}</ref><!-- cites previous 3 sentences --> In [[domestic pig]]s, the cervix contains a series of five interdigitating pads that hold the boar's corkscrew-shaped penis during copulation.<ref>{{cite web|url=http://livestocktrail.illinois.edu/swinerepronet/paperDisplay.cfm?ContentID=6274|title=The Female - Swine Reproduction|website=livestocktrail.illinois.edu|language=en|access-date=2017-03-07|archive-date=2022-02-10|archive-url=https://web.archive.org/web/20220210052921/http://livestocktrail.illinois.edu/swinerepronet/paperDisplay.cfm?ContentID=6274|url-status=dead}}</ref>

==Etymology and pronunciation==
The word ''cervix'' ({{IPAc-en|ˈ|s|ɜːr|v|ɪ|k|s}}) came to English from [[Latin]] {{lang|la|cervīx}}, which means "neck". Like its English translation, the Latin word can refer not only to the [[neck]] [of the body], but also to an analogous narrowed part of an object. Thus, the term {{lang|la|cervix uteri}} (literally "neck of the uterus") is used in Latin to refer to the uterine cervix, but in English, the word ''cervix'' used alone usually refers to it. The first attested use of the word in English to refer to the cervix of the uterus was in 1702.<ref name=ETYCERVIX2014>{{cite web | vauthors = Harper D |title= Cervix |url= http://www.etymonline.com/index.php?term=cervix&allowed_in_frame=0 |work= Etymology Online |access-date= 19 March 2014 }}</ref> 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]]'').

The Latin word {{lang|la|cervix}} was in turn used to translate the Greek word {{lang|grc|αὐχήν}} ({{transliteration|grc|auchḗn}}),<ref name=Johnston2011>{{cite book | veditors = Galen IJ | translator-last1 = Johnston I  |title=Galen: On Diseases and Symptoms |year=2011 |publisher= Cambridge University Press |isbn=978-1-139-46084-2 |page=247}}</ref> "neck". 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]].<ref name=GASPARINI2009>{{cite journal | vauthors = Gasparini R, Panatto D | title = Cervical cancer: from Hippocrates through Rigoni-Stern to zur Hausen | journal = Vaccine | volume = 27 | issue = Suppl 1 | pages = A4–A5 | date = May 2009 | pmid = 19480961 | doi = 10.1016/j.vaccine.2008.11.069 }}</ref> Greek writers usually used the term {{lang|grc|στόμαχος}} ({{transliteration|grc|stómachos}}) to refer to the [[cervical canal]]; however, there was some variation in the sense of these two words.<ref name=Johnston2011/>

== References ==
=== Citations ===
{{Reflist|30em}}

=== Cited texts ===
* {{cite web|url=http://publications.nice.org.uk/intrapartum-care-cg55/guidance |publisher=[[NICE]] |title=Intrapartum care: Care of healthy women and their babies during childbirth |date=September 2007 |url-status=dead |archive-url=https://web.archive.org/web/20140426234127/http://publications.nice.org.uk/intrapartum-care-cg55/guidance |archive-date=2014-04-26 }}

== External links ==
* {{commons category-inline|Cervix uteri}}

{{Female reproductive system}}
{{women's health}}
{{Authority control}}

[[Category:Cervix| ]]
[[Category:Mammal female reproductive system]]
[[Category:Human female reproductive system]]
[[Category:Women's health]]
[[Category:Sex organs]]