The cervix or cervix uteri is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long 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, 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 female reproductive system is made up of the internal and external sex organs that function in the reproduction of new offspring. In humans, the female reproductive system is immature at birth and develops to maturity at puberty to be able to produce gametes, and to carry a fetus to full term. The internal sex organs are the vagina, uterus, fallopian tubes, and ovaries. The female reproductive tract includes the vagina, uterus, and fallopian tubes and is prone to infections. The vagina allows for sexual intercourse and childbirth, and is connected to the uterus at the cervix. The uterus or womb accommodates the embryo which develops into the fetus. The uterus also produces secretions which help the transit of sperm to the fallopian tubes, where sperm fertilize ova produced by the ovaries. 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 paramesonephric ducts are paired ducts of the embryo in the female reproductive system that run down the lateral sides of the genital ridge and terminate at the sinus tubercle in the primitive urogenital sinus. In the female, they will develop to form the fallopian tubes, uterus, cervix, and the upper one-third of the vagina.
Cryptomenorrhea or cryptomenorrhoea, is a medical condition in which menstrual bleeding occurs but remains hidden due to a congenital septum or atresia blocking the vagina, resulting in symptoms of menstruation without external bleeding. It is commonly seen in cases of imperforate hymen. Specifically the endometrium is shed, but a congenital obstruction such as a vaginal septum or on part of the hymen retains the menstrual flow. A patient with cryptomenorrhea will appear to have amenorrhea but will experience cyclic menstrual pain. The condition is surgically correctable.
Müllerian agenesis, also known as Müllerian aplasia, vaginal agenesis, or Mayer–Rokitansky–Küster–Hauser syndrome, is a congenital malformation characterized by a failure of the Müllerian ducts to develop, resulting in a missing uterus and variable degrees of vaginal hypoplasia of its upper portion. Müllerian agenesis is the cause in 15% of cases of primary amenorrhoea. Because most of the vagina does not develop from the Müllerian duct, instead developing from the urogenital sinus, along with the bladder and urethra, it is present even when the Müllerian duct is completely absent. Because ovaries do not develop from the Müllerian ducts, affected people might have normal secondary sexual characteristics but are infertile due to the lack of a functional uterus. However, biological motherhood is possible through uterus transplantation or use of gestational surrogates.
A uterine malformation is a type of female genital malformation resulting from an abnormal development of the Müllerian duct(s) during embryogenesis. Symptoms range from amenorrhea, infertility, recurrent pregnancy loss, and pain, to normal functioning depending on the nature of the defect.
An imperforate hymen is a congenital disorder where a hymen without an opening completely obstructs the vagina. It is caused by a failure of the hymen to perforate during fetal development. It is most often diagnosed in adolescent girls when menstrual blood accumulates in the vagina and sometimes also in the uterus. It is treated by surgical incision of the hymen.
Vaginal atresia is a condition in which the vagina is abnormally closed or absent. The main causes can either be complete vaginal hypoplasia, or a vaginal obstruction, often caused by an imperforate hymen or, less commonly, a transverse vaginal septum. It results in uterovaginal outflow tract obstruction. This condition does not usually occur by itself within an individual, but coupled with other developmental disorders within the female. The disorders that are usually coupled with a female who has vaginal atresia are Mayer-Rokitansky-Küster-Hauser syndrome, Bardet-Biedl syndrome, or Fraser syndrome. One out of every 5,000 women have this abnormality.
A bicornuate uterus or bicornate uterus, is a type of mullerian anomaly in the human uterus, where there is a deep indentation at the fundus (top) of the uterus.
A uterine septum is a form of a congenital malformation where the uterine cavity is partitioned by a longitudinal septum; the outside of the uterus has a normal typical shape. The wedge-like partition may involve only the superior part of the cavity resulting in an incomplete septum or a subseptate uterus, or less frequently the total length of the cavity and the cervix resulting in a double cervix. The septation may also continue caudally into the vagina resulting in a "double vagina".
Uterus didelphys represents a uterine malformation where the uterus is present as a paired organ when the embryogenetic fusion of the Müllerian ducts fails to occur. As a result, there is a double uterus with two separate cervices, and possibly a double vagina as well. Each uterus has a single horn linked to the ipsilateral fallopian tube that faces its ovary.
Hematocolpos is a medical condition in which the vagina is pooled with menstrual blood due to multiple factors leading to the blockage of menstrual blood flow. The medical definition of hematocolpos is 'an accumulation of blood within the vagina'. It is often caused by the combination of menstruation with an imperforate hymen. It is sometimes seen in Robinow syndrome, uterus didelphys, or other vaginal anomalies.
Vaginal hypoplasia is the underdevelopment or incomplete development of the vagina. It is a birth defect or congenital abnormality of the female genitourinary system.
Hematometra is a medical condition involving collection or retention of blood in the uterus. It is most commonly caused by an imperforate hymen or a transverse vaginal septum.
A vaginal disease is a pathological condition that affects part or all of the vagina.
The fallopian tubes, also known as uterine tubes, oviducts or salpinges, are paired tubes in the human female that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In other mammals they are only called oviducts.
Cervical agenesis is a congenital disorder of the female genital system that manifests itself in the absence of a cervix, the connecting structure between the uterus and vagina. Milder forms of the condition, in which the cervix is present but deformed and nonfunctional, are known as cervical atresia or cervical dysgenesis.
Müllerian duct anomalies are those structural anomalies caused by errors in müllerian duct development during embryonic morphogenesis. Factors that precipitate include genetics, and maternal exposure to teratogens.
Herlyn-Werner-Wunderlich syndrome, also known as OHVIRA is an extremely rare syndrome characterized by a congenital birth defect of the lower abdominal and pelvic organs. It is a type of abnormality of the Müllerian ducts.
Vaginal anomalies are abnormal structures that are formed during the prenatal development of the female reproductive system and are rare congenital defects that result in an abnormal or absent vagina.
