The  sperm  differentiate inside the seminiferous tubules, then swim down these tubes, then through these special mesonephric tubules, and go down inside  Wolffian duct , to the  coelom  and finally to the organ the animal uses to transport sperm into females.


In females, the structure gives rise to the  paroöphoron . [ 1 ] : 177


The  mesonephros  ( Greek :  middle  kidney ) is one of three  excretory organs  that develop in  vertebrates . It serves as the main excretory organ of aquatic vertebrates and as a temporary kidney in reptiles, birds, and mammals. The mesonephros is included in the  Wolffian body  after  Caspar Friedrich Wolff  who described it in 1759. (The Wolffian body is composed of: mesonephros + paramesonephrotic blastema)


The mesonephros acts as a structure similar to the  kidney  that, in humans, functions between the sixth and tenth weeks of embryological life. Despite the similarity in structure, function, and terminology, however, the mesonephric nephrons do not form any part of the mature kidney or nephrons. [ 1 ]


In humans, the mesonephros consists of units which are similar in structure and function to  nephrons  of the adult kidney. Each of these consists of a  glomerulus , a tuft of  capillaries  which arises from lateral branches of dorsal aorta and drains into the  inferior cardinal vein ; a  Bowman's capsule , a funnel like structure which surrounds the glomerulus; and a  mesonephric tubule , a tube which connects the Bowman's capsule to the mesonephric duct. [ 1 ]  A unit consisting of a single glomerulus and the Bowman's capsule surrounding it is called  renal corpuscle , and a unit consisting of single renal corpuscle with its associated mesonephric tubule is called a " nephron " [ 1 ]  or "excretory mesonephric unit". [ This quote needs a citation ]


Formation of each mesonephric nephron begins when a bit of the  intermediate mesoderm  adjacent to the  mesonephric duct  differentiates to form a  mesonephric vesicle . [ 1 ]


This vesicle then elongates to form the  mesonephric tubule , attaching to the mesonephric duct on one side. Meanwhile, an artery from the dorsal aorta begins extending towards the mesonephric tubule. When these two structures contact each other, they form the glomerulus and the Bowman's capsule surrounding it. [ 1 ]  The mesonephric tubule is also known as the  Wolffian tubules  (or  Kobelt's tubules ).


On the medial side of the mesonephric duct, from the sixth cervical to the third lumbar segments, a series of tubules, the Wolffian tubules, develops. They increase in number by outgrowths from the original tubules. The change from solid masses of cells to instead become hollowed in the center. One end grows toward and finally opens into the mesonephric duct, the other dilates and is invaginated by a tuft of capillary bloodvessels to form a glomerulus. [ citation needed ]


The tubules collectively constitute the mesonephros. [ citation needed ]


The mesonephros as a whole produces urine from the 6th through the 10th week of development. [ 1 ]  Despite the similarity in structure, function, and terminology, however, the mesonephric nephrons do not form any part of the mature kidney or nephrons. [ 1 ]  As the more caudal nephrons form, the more cranial nephrons are already degenerating. In females, the mesonephros degenerates entirely, though vestigial structures such as  Gartner's ducts , the  epoophoron , and  paroophoron  are common. In males, a few of the more caudal tubules will survive and give rise to the  efferent ductules  of the  testis , [ 1 ]  the  epididymis ,  vas deferens ,  seminal vesicle , as well as vestigial structures such as the  appendix testis ,  appendix epididymis , and  paradidymis .


The mesonephros persists and forms the anterior portion of the permanent kidneys in fish and amphibians, but in reptiles, birds, and mammals, it atrophies and for the most part disappears rapidly as the permanent kidney ( metanephros ) begins to develop [ 2 ]  during the sixth or seventh week. By the beginning of the fifth month of human development, only the ducts and a few of the tubules of the mesonephros remain.


The  paramesonephric ducts  (or  Müllerian ducts ) are paired ducts of the  embryo  in the  reproductive system  of humans and other mammals that run down the lateral sides of the  genital ridge  and terminate at the  sinus tubercle  in the primitive urogenital sinus. [ 1 ]  In the female, they will develop to form the  fallopian tubes / oviducts ,  uterus ,  cervix , and the upper one-third of the  vagina .


The  female reproductive system  is composed of two embryological segments: the urogenital sinus and the paramesonephric ducts. The two are conjoined at the  sinus tubercle . [ 2 ] [ 3 ]  Paramesonephric ducts are present on the embryo of both sexes. [ 3 ] [ 4 ]  Only in females do they develop into reproductive organs. They degenerate in males of certain species, but the adjoining  mesonephric ducts  develop into male reproductive organs. The sex based differences in the contributions of the paramesonephric ducts to reproductive organs is based on the presence, and degree of presence, of  anti-Müllerian hormone .
During the formation of the reproductive system, the paramesonephric ducts are formed just lateral to the  mesonephric ducts  in both female and male embryos 6 weeks after fertilization. During this time, primordial  germ cells  migrate from the yolk sac to the  genital ridge ; a region of  mesenchyme  arising from, and running parallel with, the  mesonephros . The paramesonephric ducts are formed by the craniocaudal invagination of a ribbon of thickened coelomic epithelium that extends from the third thoracic segment caudally to the posterior wall of the urogenital sinus. The caudal parts of the paramesonephric ducts fuse into a single tube, known as the  uterovaginal primordium , [ 5 ]  before flowing into the dorsal aspect of the  urogenital sinus  at the  sinus tubercle  directly medial to the  mesonephric ducts .


The development of the paramesonephric (Müllerian) ducts is controlled by the presence or absence of  anti-Müllerian hormone  (AMH; also known as Müllerian-inhibiting substance, "MIF" for "Müllerian-inhibiting factor", "MIH" for "Müllerian-inhibiting hormone", or "APH" for anti-paramesonephric hormone). [ 6 ] [ 7 ]


AMH is a glycoprotein hormone that is secreted by  sustentacular cells  ( Sertoli cells ) in males as they begin their morphologic differentiation in response to  SRY  expression. AMH begins to be secreted around week 8, which in turn causes the paramesonephric ducts to regress very rapidly between the 8th and 10th weeks. However, small paramesonephric ducts can still be identified, and the remnants can be detected in the adult male, located in the  appendix testis , a small cap of tissue associated with the testis. Remnants of the paramesonephric ducts can also be found in the  prostatic utricle , an expansion of the prostatic urethra at the center of the  seminal colliculus .


AMH receptor-type II (AMHR-II), also known as Misr-II, causes AMH to act indirectly on mesenchymal cells surrounding the paramesonephric ducts rather than acting directly on the epithelium of the duct. [ 8 ]  This receptor activation induces the ducts to regress. The importance of mesenchyme-to-epithelial signaling is to maintain AMHR-II expression in the mesenchyme. In the absence of the Wnta7a within the duct epithelium as the ducts regress, ductal AMHR-II expression is lost, and residual paramesonephric ducts would be retained in males, throwing off the urogenital system.


Cryptorchidism  (undescended testis) or  ectopic testis  with  inguinal hernias  have been identified in human males due to AMH and AMHR-II gene mutations. Studies have revealed another AMH receptor group, AMH receptor-type I (AMHR-I), based on the AMH being a TgfB/Bmp family member. Studies have shown that ALK2, Alk3 (or Bmpr 1a) and Alk6 all serve as AMHR-I receptors. When these receptors are blocked or knocked out in mice within the paramesonephric duct mesenchyme, AMH-induced paramesonephric duct regression is lost.


In females, the paramesonephric ducts give rise to the uterine tubes, uterus, and upper portion of the vagina, while the mesonephric ducts degenerate due to the absence of male androgens. In contrast, the paramesonephric ducts begin to proliferate and differentiate in a cranial-caudal progression to form the aforementioned structures. During this time, the single-layered paramesonephric duct epithelium differentiates into other structures, ranging from the ciliated columnar epithelium in the uterine tube to stratified squamous epithelium in the vagina. [ 8 ]


The paramesonephric ducts and the mesonephric ducts share a majority of the same mesenchyme due to Hox gene expression. The genes expressed play a critical role in mediating the regional characterization of structures found along the cranial-caudal axis of the female reproductive tract.


Individuals that are 46, XY and have been tested positive for mutations in their AMH or AMH receptor genes have been known to exhibit features typical of that which are exhibited in  persistent Müllerian duct syndrome  due to the fact that the paramesonephric ducts fail to regress. When this happens the individuals develop structures that are derived from the paramesonephric duct, and also structures that are derived from the mesonephric duct. A male that has  persistent Müllerian duct syndrome  may have an upper vagina, uterus, and uterine tubes as well as  ductus deferens  along with male external genitalia. The female organs are in the correct anatomical position but the position of the testis varies. 60% to 70% of detected cases, both testes will lie in the normal position for the ovaries; about 20% to 30% of the time, one of the testis will lie within the inguinal hernial sac while in other cases both testes will lie within the same inguinal hernia sac. However whenever an individual exhibits persistent Müllerian duct syndrome, the ductus deferens will run along the lateral sides of the uterus. [ 8 ]


Anomalies that develop within the paramesonephric duct system continue to puzzle and fascinate obstetricians and gynecologists. The paramesonephric ducts play a critical role in the female reproductive tract and differentiate to form the uterine tubes, uterus, superior vagina as well as the uterine cervix. Many types of disorders can occur when this system is disrupted ranging from uterine and vaginal agenesis to the duplication of unwanted cells of the uterus and vagina. Paramesonephric malformations are usually related to abnormalities of the renal and axial skeletal system. [ 8 ]  Malfunction in the ovaries and age onset abnormalities can also be associated with most paramesonephric ducts. Most often, abnormalities are recognized once the external genitalia is no longer masked and the internal reproductive organ abnormalities become revealed. Due to a very broad range of anomalies it is very difficult to diagnose paramesonephric duct anomalies. [ 9 ]


Due to improved surgical instruments and technique, women with paramesonephric duct anomalies can have normal sexual relations. Through the use of Vecchietti and Mclndoe procedures, women can carry out their sexual activity. [ 9 ]  On another note, many other surgical advances have tremendously improved fertility chances as well as obstetric outcomes. Assisted reproductive technology makes it possible for some women who have paramesonephric duct anomalies to conceive and give birth to healthy babies.


They are named after  Johannes Peter Müller , a  physiologist  who described these ducts in his text "Bildungsgeschichte der Genitalien" in 1830.


The  nephrogenic cord  is a portion of the  urogenital ridge  which is the source of much of the  urinary system . [ 1 ]


The nephrogenic cords are bilateral condensations of the intermediate mesoderm. [ 2 ]  The cords extend from the cervical segments to the sacral segments of the embryo. The nephrogenic cords are located on the posterior wall of the embryo, which is where the kidneys are located. The nephrogenic cords go through three phases of development which overlap to some extent, both in space and in time. The 1st phase is the  pronephros , the 2nd phase is the  mesonephros  and the 3rd and final stage is the  metanephros .


In earlier conceptions of  kidney  biology, the  nephrotome  was a section of the  mesoderm  that gives rise to the  pronephros  and eventually to the rest of the  kidney .  Older texts describe the pronephros as forming through the fusion of multiple nephrotomes.


Modern visualization methods, such as  scanning electron microscopy ,  in situ hybridization , and confocal microscopy, combined with the simple approach of peeling off the epidermis to see the forming kidney, have shown that this is not the case. [ citation needed ]  Nephric  mesenchyme  separates from the intermediate mesoderm as a single elongated primordia. As this primordia begins to undergo epithelialization the anterior portions of the pronephros form rounded protrusions, which then later became the dorsal branches of the pronephros that link to nephrostomes (distinct from nephrotomes). These rounded bumps are the structures observed in histological sections that are referred to as nephrotomes. [ citation needed ]  Nephrotomes are not related to  nephrostomes , which are thin ciliated funnels that link pronephric nephrons to the coelom.


In  embryology , the  primordial phallus  refers to the  clitoris  of a female or the  penis  in the male, particularly during embryonic  development of the urinary and reproductive organs , before  sexual differentiation  is evident. This is also the case for the immature male analog, the immature  glans penis .


The  pronephric duct  is the predecessor of the  mesonephric duct  (Wolffian duct).


The development of the pronephric duct is a part of the  development of the urinary system , and the  development of the reproductive system .


In the outer part of the  intermediate mesoderm , immediately under the ectoderm, in the region from the fifth  cervical segment  to the third  thoracic segment , a series of short  evaginations  from each segment grows  dorsally  and extends  caudally , fusing successively from before backward to form the pronephric duct. This continues to grow caudalward until it opens into the ventral part of the  cloaca ; beyond the  pronephros  it is termed the  mesonephric duct . Thus, the mesonephric duct remains after the atrophy of the pronephros.


Pronephros  is the most basic of the three  excretory organs  that develop in  vertebrates , corresponding to the first stage of  kidney  development. It is succeeded by the  mesonephros , which in fish and amphibians remains as the adult kidney. In  amniotes , the mesonephros is the embryonic kidney and a more complex metanephros acts as the adult kidney. [ 1 ]  Once a more advanced kidney forms, the previous version typically degenerates by apoptosis or becomes part of the male reproductive system.


The pronephros develops from the intermediate mesoderm, as do the later kidneys. It is a paired organ, consisting of a single giant nephron that processes blood filtrate produced from glomeruli or glomera- large embryonic glomeruli. The filtrate is deposited into the coelom. It then passes through thin ciliated tubules into the pronephric nephron where it is processed for solute recovery.


The organ is active in adult forms of some primitive  fish , like  lampreys  or  hagfish . It is present at the embryo of more advanced fish and at the  larval  stage of  amphibians  where it plays an essential role in osmoregulation. In  human beings , it is rudimentary, appears at the end of the third week (day 20) and replaced by  mesonephros  after 3.5 weeks. Despite this transient appearance in mammals, the pronephros is essential for the development of the adult kidneys. The duct of the  mesonephros  forms the Wolffian duct and ureter of the adult kidney. The embryonic kidney and its derivatives also produces the inductive signals that trigger formation of the adult kidney.


The pronephros is the first in a sequence of kidneys that form in vertebrate embryos. The pronephric  primordium  develops from the  intermediate mesoderm , lying between the  paraxial (somitic) mesoderm  and the  lateral plate . In many organisms (e.g. amphibians) this primodium forms anteriorly then migrates posteriorly to fuse with the cloaca, while in others it forms along the length of the intermediate mesoderm.


In both amphibians and zebrafish, the pronephros has a single nephron attached to a nephric duct, which in turn is linked to the cloaca. Although these kidneys have a simple anatomical organization with only a single nephron, the nephrons have a segmental and functional complexity that is very similar to that in more complex kidneys such as  mesonephroi  and  metanephroi .


One unique feature of pronephroi is the arrangement by which the glomerular filtrate is generated and collected by the nephron. In pronephroi the  glomerulus  (or glomus if it extends over multiple body segments) projects into the coelom rather than into the proximal tip of the nephron. The glomerular filtrate flows directly into the coelom, or a dorsal compartment of the coelom known as the nephrocoel. In jawless fishes, the pronephric glomus projects into the pericardial cavity. Fluids are swept from the filtration cavity into the nephron through ciliated funnels known as nephrostomes. These thin epithelial tubes are densely packed with cilia and have a distinct morphology to the other tubular epithelia of the kidney.


Older anatomical texts describe the pronephros as condensing from nephrotomes, but modern visualization techniques have shown that this represents a histological artifact.


Once the more complex mesonephros forms the pronephros undergoes apoptosis in amphibians. In fishes, the nephron degenerates but the organ remains and becomes a component of the immune system.


In mammals, a functional pronephros, in the context of an organ performing waste excretion or osmoregulation, does not develop. However, a kidney primordium that runs along the intermediate mesoderm does form and links up to the cloaca. This duct is known as the pronephric duct, mesonephric duct or  Wolffian duct . While this transient primordium never forms functional nephrons, the duct derived from it is essential to the development of the more complex later kidneys. [ 1 ]


The  rete ovarii  ( pl. :  retia ovarii ) is a structure formed from the primary  sex cords  in females. [ 1 ]


It is the  homologue  of the  rete testis  in males. [ 2 ]  It is a narrow  hilus , at which  nerves  and  vessels  enter the  ovary . In the  medulla  of the  mammalian  ovary near the hilus are small masses of blind  tubules  or solid cords—the rete ovarii—which are homologous with the rete testis in the male. The microscopic right ovary of  birds  usually consists only of medullary tissue.


The rete ovarii is important in the control of meiosis in the maturing ovary. Cells of the rete ovarii also differentiate to form granulosa cells. The rete is also attributed with secretory capacity, a hypothesis supported by the observation of secretory material in the lumen of rete tubules in several species. [ 3 ]


Sex cords  are embryonic structures which eventually will give rise (differentiate) to the adult  gonads  (reproductive organs). [ 1 ]  They are formed from the  genital ridges  - which will develop into the gonads - in the first 2 months of  gestation  (embryonic development) which depending on the sex of the  embryo  will give rise to male or female sex cords. [ 2 ]  These epithelial cells (from the genital ridges) penetrate and invade the underlying  mesenchyme  to form the primitive sex cords. [ 3 ]  This occurs shortly before and during the arrival of the  primordial germ cells  (PGCs) to the paired genital ridges. [ 3 ]  If there is a Y chromosome present, testicular cords will develop via the  Sry gene  (on the Y chromosome): repressing the female sex cord genes and activating the male. [ 4 ] [ 5 ]  If there is no Y chromosome present the opposite will occur, developing ovarian cords. [ 6 ] [ 7 ]  Prior to giving rise to sex cords, both XX and XY embryos have  Müllerian ducts  and  Wolffian ducts. [ 2 ]  One of these structures will be repressed to induce the other to further differentiate into the external genitalia. [ 2 ]


Once the genital ridge has committed to becoming male sex cords,  Sertoli cells  develop. [ 4 ]  These cells then induce the production and organisation of cells making up the testicular cords. [ 2 ]  These cords will eventually become the testes, which in turn produce  hormones , in particular  testosterone . [ 8 ]  These hormones drive the formation of the other male sex characteristics, and induce testicular descent out of the abdomen. [ 4 ]  These hormones also cause the development of the male reproductive tract. [ 4 ]  Embryos are formed with Wolffian and Mullerian ducts, which will either become the male or female reproductive tract, respectively. [ 8 ]  In a male embryo, the testicular cords will induce the development of the Wolffian duct into the  vas deferens ,  epididymis  and the  seminal vesicle  and cause the repression and regression of the Mullerian duct. [ 4 ]  The other male sex organs (ex. the prostate) as well as external genitalia are also formed under the influence of testosterone. [ 4 ]


Female sex cord development depends on specific genes being expressed, where multiple pro-ovarian genes (including  Wnt4, FoxL2,  and  Rsp01 ) [ 9 ] [ 10 ] [ 11 ]  and the lack of  Sry  gene expression are responsible. [ 2 ]  The lack of testosterone allows for Müllerian duct proliferation, and Wolffian duct repression. [ 2 ]  The lack of male sex hormones gives rise to female sex cords and subsequent genitalia differentiation, rather than a presence of female sex hormones. [ 2 ]  After inducing female sex cord formation, coordination between multiple genes ( Bmp, Pax2, Lim1, and Wnt4  in mice) is required for Müllerian duct development. [ 2 ]  Once the Müllerian ducts are determined, genes contributing to cell identity and positioning (specifically,  Hox genes ) play a key role in developing female reproductive structures. [ 12 ] [ 2 ]  The Hox genes are expressed in specific combinations to give rise to the  fallopian tubes , uterus, and upper region of the vagina. [ 2 ] [ 13 ]


Developing internal female genitalia, from the Müllerian ducts, occurs in three phases. First, cells are directed to proliferate on the female reproductive structure development pathway. [ 13 ]  Phase two is invagination: referring to the ducts folding in on themselves, forming openings of the fallopian tubes. [ 13 ]  In phase three, Müllerian ducts proliferate and elongate, subsequently forming the uterus and upper region of the vagina. [ 13 ]  Fallopian tubes form at the end closer to the head of the body, and the uterus and upper portion of the vagina form at the opposite end. [ 13 ]


In early prenatal development,  amphibians  and  elasmobranchs  have gonads with a dual structure; A gonadal cortex, associated with ovarian  differentiation , and a gonadal medulla, associated with testicular differentiation. [ 14 ] [ 15 ] [ 16 ]  In contrast,  amniotes  have single-structure gonads. [ 13 ]  Sex-specific development is dependent on the fate of the primary sex cord. [ 14 ]  There are also species-specific anomalies in sex cord development. Freemartin cattle are one notable phenomenon of abnormal gonad development. [ 17 ] [ 18 ]  These are genetically female cattle that develop testicle-like structures in replacement of ovaries due to exchange of blood during development in  parabiosis  with male twin(s). [ 17 ] [ 18 ]


The  urachus  forms from the distal end of the  allantois  in the  embryo , and develops into a closed cord between the base of the  bladder , and the  navel . [ 1 ]  It drains the bladder of the  fetus  that joins and runs within the  umbilical cord . [ 2 ]  The fibrous remnant lies in the  space of Retzius , between the  transverse fascia  anteriorly and the  peritoneum  posteriorly. At birth, the urachus develops into the  median umbilical ligament . [ 3 ] [ 4 ]


The part of the  urogenital sinus  related to the bladder and urethra absorbs the ends of the  Wolffian ducts  and the associated ends of the  renal diverticula . This gives rise to the  trigone of the bladder  and part of the  prostatic urethra .


The remainder of this part of the urogenital sinus forms the body of the bladder and part of the prostatic urethra. The apex of the bladder stretches and is connected to the  umbilicus  as a narrow canal. This canal is initially open, but later closes as the urachus goes on to definitively form the  median umbilical ligament .


Failure of the inside of the urachus to be filled in leaves the urachus open. The telltale sign is leakage of urine through the umbilicus. This is often managed surgically. There are four anatomical causes:


The urachus is also subject to neoplasia.  Urachal adenocarcinoma  is histologically similar to adenocarcinoma of the bowel. Rarely, urachus carcinomas can metastasise to other regions of the body, including pelvic bones and the lung. [ 7 ]


One urachal mass has been reported that was found to be a manifestation of  IgG4-related disease . [ 8 ]


This article incorporates text in the  public domain  from  page 1213  of the 20th edition of   Gray's Anatomy   (1918)


The  ureteric bud , also known as the  metanephric diverticulum , [ 1 ] : 50   is a protrusion from the  mesonephric duct  during the  development of the urinary and reproductive organs . [ 2 ] [ 3 ]  It later develops into a conduit for urine drainage from the kidneys, which, in contrast, originate from the  metanephric blastema .


The  primary urethral groove  or  urethral groove  is a temporary linear indentation on the underside (ventral side) of the male  penis  during embryonic development.


In humans, it typically appears around eight weeks of gestation and becomes closed into a normal  male urethra  by the twelfth week.


Failure of complete closure can be associated with  hypospadias . [ 1 ]


The  urogenital sinus  is a body part of a human or other  placental  only present in the  development of the urinary  and  reproductive organs .  It is the ventral part of the cloaca, formed after the  cloaca  separates from the  anal canal  during the fourth to seventh weeks of development. [ 1 ]


In males, the UG sinus is divided into three regions: upper, pelvic, and phallic.   The upper part gives rise to the  urinary bladder  and the pelvic part gives rise to the prostatic and membranous parts of the  urethra , [ 1 ]  the  prostate  and the  bulbourethral glands  (Cowper's). The phallic portion gives rise to the spongy (bulbar) part of the urethra and the  urethral glands  (Littré's).


In females, the pelvic part of the UG sinus gives rise to the  sinovaginal bulbs , structures that will eventually form the inferior two thirds of the  vagina .  This process begins when the lower tip of the  paramesonephric ducts , the structures that will eventually form the  uterus  and  vaginal fornices , come in contact with the UG sinus.  Shortly afterwards, the  sinovaginal bulbs  form as two solid  evaginations  of the UG sinus. Cells in these bulbs divide to form a solid  vaginal plate , which extends and then canalizes (hollows) to form the inferior portion of the vagina. [ 2 ]  The female urogenital sinus also gives rise to the urethra,  vestibule ,  Skene's glands  and  Bartholin's glands .


A  urogenital sinus anomaly  is also a rare  birth defect  in  women  where the  urethra  and  vagina  both open into a common channel. [ 3 ] [ 4 ]


A  persistent cloaca  is a disorder where the  rectum ,  vagina , and  urinary tract  meet and fuse, creating a  cloaca , a single common channel. [ 5 ]


In many mammals (excluding  homonids  and some rodents), [ 6 ]  the urogenital sinus refers to the sinus in which the openings to the female's urethra and vagina are found. [ 6 ] [ 7 ] [ 8 ] [ 9 ]  However, this term may also apply to some male mammals.


Vaginal anomalies  are  abnormal structures  that are formed (or not formed) during the prenatal development of the female reproductive system and are rare congenital defects that result in an abnormal or absent vagina. [ 1 ]


When present, they are often found with uterine, skeletal and urinary abnormalities. [ 2 ] [ 3 ]  This is because these structures, like the vagina, are most susceptible to disruption during crucial times of organ-genesis. Many of these defects are classified under the broader term  Müllerian duct anomalies . [ 2 ] [ 4 ]  Müllerian duct anomalies are caused by a disturbance during the embryonic time of genitourinary development. [ 5 ]


The other isolated incidents of vaginal anomalies can occur with no apparent cause. Oftentimes vaginal anomalies are part of a cluster of defects or syndromes. In addition,  inheritance  can play a part as can prenatal exposure to some  teratogens . [ 2 ] [ 6 ] [ 7 ] [ 8 ]  Many vaginal anomalies are not detected at birth because the external genitalia appear to be normal. [ 2 ]  Other organs of the  reproductive system  may not be affected by an abnormality of the vagina. The uterus,  fallopian tubes  and ovaries can be functional despite the presence of a defect of the vagina and external genitalia. [ 2 ]


A vaginal anomaly may not affect fertility. Though it depends on the extent of the vaginal defect, it is possible for  conception  to occur. In instances where a functional ovary exists,  IVF  may be successful. Functioning ovaries in a woman with a vaginal defect allows the implantation of a fertilized ovum into the uterus of an unaffected gestational carrier, usually another human. A successful conception and can occur. [ 9 ] [ 2 ]  Vaginal length varies from 6.5 to 12.5 cm. Since this is slightly shorter than older descriptions, it may impact the diagnosis of women with vaginal agenesis or hypoplasia who may unnecessarily be encouraged to undergo treatment to increase the size of the vagina. [ 10 ]


Vaginal anomalies may cause difficulties in urination, conception, pregnancy, impair sex. Psychosocial effects can also exist. [ 11 ]


Some anomalies are found upon examination shortly after birth or when the development of sexual characteristics does not progress as expected. Defects that prevent menstrual flow become obvious when amenorrhea occurs. [ citation needed ]


Syndromes may take longer to identify since they are rare and often involve errors in metabolism. Many syndromes share the same signs and symptoms. [ citation needed ]


Uterine defects can accompany vaginal abnormalities:


Women with uterine abnormalities may have associated renal abnormalities including unilateral renal agenesis. [ 14 ]


Some congenital syndromes present with vaginal anomalies in association with other serious conditions. These include  Fraser syndrome ,   WNT4 deficiency , and  Bardet-Biedl  syndrome, [ 15 ] [ 16 ] [ 17 ] [ 18 ]  Isolated incidents of vaginal anomalies can occur with no apparent cause and in other instances these anomalies are part of a  syndrome  or cluster of other abnormalities. The origin of many vaginal anomalies is due to a disturbance during the  embryonic  stage of  genitourinary  development. [ 5 ]  Inheritance can play a part as can prenatal exposure to  hormones  and  teratogens . [ 2 ] [ 7 ]  Though the presence of a vaginal anomaly does not necessarily prevent conception and a successful pregnancy when a functional uterus and ovaries are present, vaginal anomalies increase the risk of miscarriage. [ 19 ] [ 9 ] [ 2 ]


Prenatal exposure to some  hormones  can cause vaginal anomalies as can the lack of necessary hormones needed for normal development. [ 39 ]   Diethylstilbestrol  (DES), also known formerly (and inappropriately) as  stilboestrol , is a  synthetic   nonsteroidal estrogen  and teratogen that can cause vaginal abnormalities in the developing embryo. [ 40 ]


The cause of isolated cases of vaginal anomalies can not always be identified, though disruption of the embryonic development of the vagina likely plays a significant role. [ citation needed ]


Imaging studies are usually the most useful in diagnosing vaginal anomalies including retrograde contrast studies. [ 1 ]  An  anomaly scan  can be helpful, especially detecting the presence of a urogenital syndrome. Genetic and metabolic defects require further testing to support a diagnosis. [ citation needed ]


Vaginal anomalies are treated surgically. [ 41 ]  A 'neo-vagina' can be constructed for those girls and women who do not have a vagina. [ 42 ] [ 43 ]  Vaginal septa are treated surgically. [ 44 ] [ 45 ]


The most common vaginal anomaly is an  imperforate hymen . This anomaly occurs often enough that it can be detected by some pediatricians shortly after birth. It can be corrected through a minor surgery and may be delayed until puberty. [ 46 ]  The hymen can be unusually thick or partially obstructed by the presence of fibrous bands of  tissue . An imperforate hymen can also present with other abnormalities such as septa. An imperforate hymen can be displaced and its location may not be where it is expected. Other abnormalities of the hymen can exist including the presence of septa, displacement and a hymen that consists of microperforations. [ 47 ] [ 19 ]  Uncommonly, a double hymen is present. [ 48 ] [ 49 ] [ 50 ]  The imperforate hymen is treated by excision and drainage. Sometimes a small border of hymenal tissue is left around the opening of the vagina. [ 51 ]


Congenital adrenal hyperplasia  can cause the abnormal development of the vagina. [ 52 ] [ 53 ] [ 54 ]   Vaginal adenosis  is the abnormal presence of cervical and uterine tissue within the wall of the vagina. [ 55 ]  Ten percent of women have this condition and remain unsymptomatic. It rarely develops into a malignancy. [ 56 ]   Cloacal exstrophy  is a condition when two vaginas are present. [ 57 ] [ 58 ] [ 27 ]   Vaginal agenesis  or the complete absence of the vagina affects 1 out of 5,000 women. [ 35 ]  A hemivagina is the abnormal presence of a partial vagina that is attached to the wall of the functioning vagina. The  hemivagina does not open to the normal vagina and is attached to an abnormal, second uterus. [ 59 ]   Vaginal hypoplasia  is the under-development of the vagina and is found in instances of  complete androgen insensitivity syndrome . [ 60 ] [ 61 ] [ 15 ]   Vaginal septa  are structures consisting of fibrous tissue that block the vagina. [ 57 ] [ 62 ]  The tissue extends horizontally, blocking or partially blocking the vaginal canal or transversely essentially creating two vaginas that connect to a normal uterus. [ 63 ] [ 64 ]  Septa can prevent menstrual flow and result in painful intercourse, though some women do not have symptoms. [ 65 ] [ 60 ] [ 63 ]  Many vaginal anomalies are not detected at birth because the external genitalia can appear to be normal. [ 2 ]


The occurrence of vaginal defects varies widely and some are only known from case studies. The prevalence of an imperforate hymen is 1 in 1000. [ 66 ]


Notable is the mention of vaginal anomalies and pelvic organ prolapse in older cultures and locations. [ 78 ]  In 1500 B.C. Egyptians wrote about the "falling of the womb". In 400 B.C. a Greek physician documented his observations and treatments:


"After the patient had been tied to a ladder-like frame, she was tipped upward so that her head was toward the bottom of the frame. The frame was then moved upward and downward more or less rapidly for approximately 3–5 min. As the patient was in an inverted position, it was thought that the prolapsing organs of the genital tract would be returned to their normal position by the force of gravity and the shaking motion." [ 78 ]


Hippocrates  also described the prolapse of other organs out through the vagina. [ 78 ]  In 1521,  Berengario da Carpi  performed the first surgical treatment for prolapse. This was to tie a rope around the prolapse, tighten it for two days until it was no longer viable and cut it off. Wine, aloe, and honey were then applied to the stump. [ 78 ]


References regarding the existence of vaginal anomalies related to müllerian defects have been traced back to 300 BC when a historian described a case of vaginal agenesis. [ 79 ]


In 1823, other physicians proposed that vaginoplasty may provide treatment for pelvic organ prolapse. In 1830, the first dissection of the vagina was performed on a living woman. Other vaginal repairs were described in 1834 and treatment sometimes the suturing the edges of a vaginal defect. In 1859 a solution to vaginal elongation was to remove the cervix. [ 78 ]  In 1866, methods that resembled those used today came into practice. Surgery on the anterior vaginal wall at this time did not have to involve full-thickness repairs to be successful. Sim subsequently developed another procedure that did not require the full-thickness dissection of the vaginal wall. Shortly after this time it was proposed that reattaching the vagina to support structures was more successful and resulted in less recurrence. This same proposal was proposed again in 1976 but further studies indicated that the recurrence rate was not better. Further advances in 1961 began when surgeons started to reattach of the anterior vaginal wall to Cooper's ligament. [ 78 ]


In 1955, surgical mesh began to be used to strengthen pelvic tissue. In 1970, tissue from pigs began to be used to strengthen the anterior vaginal wall in surgery. Beginning in 1976, improvement in suturing began along with the surgical removal of the vagina being used to treat prolapse of the bladder. In 1991, assumptions about the detailed anatomy of the pelvic support structures began to be questioned regarding the existence of some pelvic structures and the non-existence of others. More recently, the use of stem cells, robot-assisted laparoscopic surgery are being used during vaginectomy and vaginoplasty. [ 78 ]


The  vaginal process  (or  processus vaginalis ) is an  embryonic  developmental outpouching of the  parietal peritoneum . It is present from around the 12th week of gestation, and commences as a peritoneal outpouching.


In males, it precedes the  testes  in their descent down within the  gubernaculum , and closes. This closure (also called  fusion ) occurs at any point from a few weeks before birth, to a few weeks after birth. The remaining portion around the testes becomes the  tunica vaginalis . [ 1 ]  If it does not close in females, it forms the  canal of Nuck . [ 2 ]


Failure of closure of the vaginal process leads to the propensity to develop a number of abnormalities. Peritoneal fluid can travel down a patent vaginal process leading to the formation of a  hydrocele . Persistent patent processus vaginalis is more common on the right than the left. Accumulation of blood in a persistent processus vaginalis could result in a  hematocele .


There is the potential for an indirect  inguinal hernia  to develop, although not all people with a patent vaginal process will develop one. The more patent the vaginal process, the more likely the patient is to develop a hernia. Congenital malformation of the vaginal process is also the leading cause of  testicular torsion , since lack of attachment to the inner lining of the scrotum leaves the testicles free to twist.


A  vaginal septum  is a  vaginal anomaly  that is partition within the  vagina ; such a  septum  could be either longitudinal or transverse. In some affected women, the septum is partial or does not extend the length or width of the vagina. [ 1 ]   Pain during intercourse  can be a symptom. A longitudinal vaginal septum develops during  embryogenesis  when there is an incomplete fusion of the lower parts of the two  Müllerian ducts . As a result, there may appear to be two openings to the vagina. There may be associated duplications of the more cranial parts of the Müllerian derivatives, a double  cervix , and either a  uterine septum  or  uterus didelphys  (double uterus). [ 1 ] [ 2 ]  A transverse septum forms during embryogenesis when the Müllerian ducts do not fuse to the  urogenital sinus . A complete transverse septum can occur across the vagina at different levels. Menstrual flow can be blocked, [ 3 ]  and is a cause of primary  amenorrhea . The accumulation of menstrual debris behind the septum is termed  cryptomenorrhea . Some transverse septa are incomplete and may lead to  dyspareunia  or obstruction in  labour . [ 4 ] [ 5 ]


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The  genitourinary system , or  urogenital system , are the  sex organs  of the  reproductive system  and the  organs  of the  urinary system . [ 1 ]  These are grouped together because of their proximity to each other,  their common embryological origin  and the use of common pathways. Because of this, the systems are sometimes imaged together. [ 2 ]  In  placental mammals  (including humans), the male  urethra  goes through and opens into the  penis  while the female urethra and  vagina  empty through the  vulva . [ 3 ]


The term "apparatus urogenitalis" was used in  Nomina Anatomica  (under  splanchnologia ) but is not used in the current  Terminologia Anatomica .


The urinary and reproductive organs are developed from the  intermediate mesoderm . The permanent organs of the adult are preceded by a set of structures that are purely embryonic and that, with the exception of the ducts, disappear almost entirely before the end of fetal life. These embryonic structures are on either side: the  pronephros , the  mesonephros  and the  metanephros  of the  kidney , and the  Wolffian  and  Müllerian ducts  of the  sex organ . The pronephros disappears very early; the structural elements of the mesonephros mostly degenerate, but the  gonad  is developed in their place, with which the Wolffian duct remains as the duct in males, and the Müllerian as that of the female. Some of the tubules of the mesonephros form part of the permanent kidney.


The urethra of an adult human female is 3-4 cm long. [ 4 ]  The female urethra is located between the bladder neck to the external urethral orifice and is behind the symphysis pubis. [ 4 ] The urethral wall is composed of an inner epithelial lining, a sub-mucosa layer containing vascular supply, a thin fascial layer, and two layers of smooth muscle. [ 4 ]


The urethra of an adult human male is 18-20 cm long.  [ 4 ] It has a diameter of 8-9 mm. [ 4 ] The male urethra is divided into two sections.


Disorders of the genitourinary system includes a range of disorders from those that are asymptomatic to those that manifest an array of signs and symptoms.  Causes for these disorders include congenital anomalies, infectious diseases,  trauma , or conditions that secondarily involve the urinary structure.


To gain access to the body,  pathogens  can penetrate mucous membranes lining the genitourinary tract.


Urogenital malformations include:


As a medical specialty,  genitourinary pathology  is the subspecialty of  surgical pathology  which deals with the  diagnosis  and characterization of  neoplastic  and non-neoplastic  diseases  of the  urinary tract , male genital tract and testes. However, medical disorders of the kidneys are generally within the expertise of  renal pathologists . Genitourinary  pathologists  generally work closely with  urologic surgeons .


Blennorrhoea  aka  blennorrhagia  or  myxorrhoea  ('blenno' mucus, 'rrhoea' flow), is a  medical  term denoting an excessive discharge of watery mucus, especially from the urethra or the vagina, and also used in  ophthalmology  for an abnormal discharge from the eye, but now regarded as a synonym for  conjunctivitis  and accordingly rarely used. [ 1 ] [ 2 ] [ 3 ]


Inclusion blennorrhoea  aka   chlamydial conjunctivitis  or  swimming pool conjunctivitis , is a condition affecting infants born to women infected with inclusion conjunctivitis of the  urogenital tract , frequently caused by  Chlamydia trachomatis , a sexually transmitted organism and often going unnoticed as a mild infection. Such infants may develop acute neonatal conjunctivitis within a few days of birth, and smears from their eyes reveal the presence of characteristic  inclusion bodies . If left untreated the infection may persist for 3–12 months and heal, but could result in permanent scarring of the conjunctiva. [ 4 ]


Genital  regeneration  encompasses various forms of treatment for genital anomalies. The goal of these treatments is to restore form and function to male and  female genitalia  by taking advantage of innate responses in the body. In order to do this, doctors have  experimented  with  stem cells  and  extracellular matrix  to provide a framework for regenerating missing structures. More research is needed to successfully move the science from laboratory trials to routine procedures. [ 1 ] [ 2 ]


Patients who can benefit most from this field are those who have congenital defects, cancer, injuries that have excised parts of their  genitalia  (most notably soldiers in war),  and men looking to reverse circumcision and women wishing to reverse forms of female genital mutilation. As is the case in most scientific pursuits, these accomplishments might be applied to other forms of regeneration and vice versa as scientists continue to study  tissue engineering .


In the last decade, there have been notable accomplishments in utilizing extracellular matrices (ECM) and stem cells to reconstruct lost tissue. These cover a range of structures including the genitals. [ 3 ]  Professor Atala and his group at Wake Forest University's Institute of Regenerative Medicine have successfully regenerated fully functioning rabbit penises that were excised for the sake of the experiment. Autologous cells were attached to a three-dimensional collagen matrix. Once formed, the structure was attached and tested for functionality. [ 1 ] [ 4 ]


An Italian doctor named Dr. Cinzia Marchese has successfully reconstructed the inner mucosal lining of congenitally deformed vaginas by using an enzyme to break down the abnormal lining, then inserting stem cells to remodel the walls and restore normal functionality. [ 5 ]


There are currently no therapies available for men attempting to clinically regenerate structures of the human penis. Also, for women there are no therapies that use autologous cells to regenerate the clitoris, sometimes removed in cases of  female genital mutilation .


The following therapies do not rely on autologous cells:


A vibration technique developed by Ellen L. Barnard and Myrtile Wilhite claims to promote regeneration in the vaginal cell lining. [ 6 ]  A topical cream developed by Lyle Corporate Development, Inc., claims to encourage regeneration of tissues in the vulva that have undergone cellular hypoxia. [ 7 ]


There are manual reconstruction techniques such as those developed by French surgeon  Pierre Foldès . [ 8 ]  His procedure provides women with a clitoris, but is not considered a regenerative medicine. [ 9 ]


Some organizations which perform research into, or conduct regeneration procedures, include the  Wake Forest Institute for Regenerative Medicine , the  United States Department of Defense , [ 10 ]  and the  California Institute for Regenerative Medicine .


The  genitourinary tract , or simply the  urinary tract , consists of the kidneys, ureters, bladder, and the urethra. The  kidney  is the most frequently injured. [ 1 ]  Injuries to the kidney commonly occur after automobile or  sports -related accidents. [ 1 ]  A  blunt force  is involved in 80-85% of injuries. Major decelerations can result in vascular injuries near the kidney's  hilum . Gunshots and knife wounds and fractured ribs can result in penetrating injuries to the kidney.


Pelvic fractures can damage the  urethra  and bladder.


In 90% of bladder injuries, there is a concurrent  pelvic fracture . [ 1 ]  Pelvic bone fragments penetrate and perforate the bladder. [ 1 ]  Perforations can be either  extraperitoneal  or  intraperitoneal . [ 1 ]  Intraperitoneal perforations allow for urine to enter the  peritoneal cavity . Symptoms typically develop immediately if the urine is infected. [ 1 ]  Otherwise sterile urine may take days to cause symptoms. [ 1 ]


Blood in the urine after abdominal trauma suggests a urinary tract injury. [ 1 ]  Renal injuries are suggested by lower  rib fractures . [ 1 ]  Bladder and urethral injuries are suggested by pelvic fractures. [ 1 ]


The  urethral meatus  should be examined after trauma. [ 1 ]  Blood at the  urethral  meatus precludes insertion of a  foley catheter  into the bladder. [ 1 ]  Erroneously placing a foley in this situation can result in infections of  periprostatic  and  perivesical   hematomas  or conversion of a partial transection to a complete urethral transections. [ 1 ]  Blood at the urethral meatus suggests an injury to the urethra. [ 1 ]  Otherwise a foley catheter can be placed into the bladder and hematuria can be assessed for. [ 1 ]


Hemodynamically  stable individuals should undergo further  radiographic  assessment. [ 1 ]  Abdominal  computed tomography  (CT) with contrast can detect retroperitoneal hematomas, renal lacerations, urinary extravasation, and renal arterial and venous injuries. [ 1 ]  A repeat scan ten minutes after the first is recommended. [ 1 ]


The purpose of this study is to identify and characterize injuries to the urethra. [ 1 ]  The tip of a small (12F) foley catheter is placed in the urethral meatus. [ 1 ]  The catheter remains fixed after 3 mL of water are instilled into the foley catheter's balloon. [ 1 ]  Radiographic films are taken as 20 mL of water-soluble contrast material are injected [ 1 ]  This outlines the urethra from the  urethral meatus  to the  bladder neck . [ 1 ]  If injuries exist, the location can be determined. [ 1 ]


The purpose of this study is to identify bladder perforations. [ 1 ]  The bladder needs to be adequately distended with contrast medium. [ 1 ]  300 mL or more are generally recommended. [ 1 ]  The study has two films. One film is taken when the bladder is adequately distended and filled with contrast. [ 1 ]  The next film is taken after the bladder is emptied without the assistance of a foley catheter. [ 1 ]


Helpful in identifying injuries to the kidney's  parenchyma  and vasculature. [ 1 ]


Management depends on what part of the urethra was injured and to what extent. [ 1 ]  The two broad anatomical separations are the posterior and anterior urethra. [ 1 ]  The posterior urethra includes the prostatic and membranous urethra. [ 1 ]  The anterior urethra includes the bulbous and pendulous portion. [ 1 ]


The  membranous urethra  can be separated from the  prostate 's apex after blunt trauma. [ 1 ]  The urethra should not be catheterized. [ 1 ]  Initial management should be the creation of a suprapubic cystostomy for urine drainage. [ 1 ]  The bladder should be opened in the midline so to facilitate inspection of bladder lacerations. [ 1 ]  Perforations can be closed with absorbable sutures. [ 1 ]  The suprapubic cystostomy remains in place for three months. [ 1 ]  Incomplete urethral disruptions heal spontaneously and the suprapubic cystostomy can be removed after three weeks for these injuries. [ 1 ]  Before removing a cystostomy, a  voiding cystourethrography  should demonstrate no urine extravasation. [ 1 ]  Delayed urethral reconstruction may be performed within 3 months. [ 1 ]  This typically entails a direct excision of the now strictured area and anastomosis of the  bulbous urethra  to the prostate's apex. [ 1 ]  A urethral catheter and suprapubic cystostomy should be left in place. [ 1 ]  These are removed within a month. [ 1 ]


The  genitourinary microbiome  refers to the aggregate of  bacteria ,  archaea , and  fungi  that may colonize the human genital and urinary tract. Some analyses also include any  viruses  and  protists  present. This term encompasses both the human urinary microbiome (urobiome), as well as the genital microbiome, and is a subset of the  human microbiome .


The study of the genitourinary microbiome is young; only the  vaginal microbiome  has been thoroughly characterized. The development of next-generation sequencing has allowed researchers to use  16S ribosomal RNA  to identify organisms present in asymptomatic or “healthy” individuals.


Studies of the  human microbiome  traditionally lack in discussion of the genitourinary system due to the long-standing misnomer that urine that does not grow  colony-forming units  (CFUs) in standard  microbiological cultures  is "sterile". [ 1 ]  This has stunted research on microbiomes of the bladder or urethra.


There is now evidence to support colonization of the female bladder [ 2 ]  as well as the male lower urinary tract. [ 3 ]  The significance of the genitourinary microbiome on disease incidence or progression is not yet understood. Perturbations in the genitourinary microbiome could have implications for patients with  urinary tract infections  (UTIs), sexually transmitted infections (STIs), interstitial cystitis and chronic prostatitis.


In both males and females,  Bacillota ,  Actinobacteria ,  Bacteroidetes ,  Proteobacteria , and  Fusobacteria  make up the general phyla of the human urinary microbiome, [ 4 ]   with Firmicutes/Bacillota and Bacteroidetes accounting for about 74% of relative abundance. [ 5 ]   Studies up until 2018 found the general bacterial species composition of the urinary microbiome to consist of primarily  Lactobacillus ,  Gardnerella , and  Streptococcus . In 2021, Qin et al performed a thorough 16S RNA sequencing of asymptomatic subjects and found  Prevotella ,  Escherichia - Shigella , and  Veillonella  in addition to the previously mentioned classes. [ 5 ]  It is unclear whether  Prevotella  may be more predominantly found in Chinese populations; [ 6 ]  more studies are needed in diverse populations to determine possible genetic, diet-related, and geographical factors. Current findings agree with the species identified in the  Human Microbiome Project ; [ 7 ]  however, the genitourinary microbiome was notably excluded from analysis.


Anatomical and hormonal factors can influence the composition of the genitourinary microbiome. Differences mostly lie at the species level rather than the phylum level. Research shows a higher prevalence of organisms in females that correspond with healthy vaginal flora. There is evidence to support that the urinary microbiome changes with age, possibly due to changes in hormones, diet, and metabolism. Differences between age groups are seen in relative abundance of species. Women tend to have a decrease in  Lactobacillus  abundance after menopause, which reinforces the idea that hormones may affect microbiome composition.


The most common disease-causing organisms in urinary tract infections are  Escherichia coli ,  Enterococcus faecalis ,  Klebsiella  species,  Pseudomonas aeruginosa , Proteus  species and  Streptococcus  species. [ 8 ]  Many of these species may also be present in a “typical” human urobiome, but several factors influence the makeup and proportions of organisms, including age, gender, and diet.


Studies have found that utilizing expanded incubation procedures, such as 5% CO2, allows for the growth of more fastidious organisms. This mirrors updates from the Human Microbiome Project, which suggests biodiversity of microorganisms colonizing every part of the human body may be higher than previously thought. The acceleration of various testing methods, like  Polymerase Chain Reaction  (PCR) and 16S  RNA sequencing , have allowed for a more thorough understanding of clinical samples that may not meet clinical requirements for significant growth. Data from molecular studies suggests that non-culturable or slow-growing organisms may be present in urine samples and not identified due to the limitations of standard microbiological culture parameters. [ citation needed ]


Uncontaminated urine samples are difficult to obtain without  urinary catheterization  due to the proximity of the urinary system to genitals and the GI tract. This is especially a problem for female patients, who are often uninformed about proper clean-catch urine collection procedure or the significance of skin flora in urinary cultures. It is likely to see streptococci or staphylococci as a result of contamination from vaginal fluids, as these gram-positive organisms grow favorably in standard incubation parameters. Using correct clean-catch urine collection procedure can reduce the likelihood of contamination. For women, this requires using a sterile wipe on the area prior to collection, spreading the labia, and collecting a mid-stream sample.


Many researchers will group cohorts into "urotypes" with similar microbiological community structure since a single "typical" genitourinary microbiome community does not exist. [ 3 ] [ 9 ]  For example, a urotype may be characterized by being dominated by  Gardnerella ,  Streptococcus , or  Staphylococcus . More research is needed to understand the influence of genetic and environmental factors on the development of urotypes.


The vaginal microbiome has been thoroughly characterized. Organisms belonging to the  vaginal flora  may be seen in urine cultures due to contamination or collection method. [ 10 ]  The most abundant organisms in the vaginal microbiome are Lactobacilli, which do not grow in standard microbiological urine cultures. Some common organisms from this genus found in the vaginal microbiome include  L. crispatus, L. iners, L. jensenii , and  L. gasseri.


Characterization of the microbiome of the internal male reproductive system has not been performed. Males were not previously known to have a genital microbiome due to the connection to the urinary system, but research no longer supports sterility of the urethra and/or bladder in males or females. [ citation needed ]


The full implications of disturbances in the genitourinary microbiome on disease is not known. The main targets of study are recurrent and polymicrobial UTIs, interstitial cystitis and chronic prostatitis. Disturbances in the microbiome may affect the occurrence or severity of sexually transmitted infections. A 2010 study found that urine samples from men with STIs had higher presence of slow-growing or non-culturable bacteria.


Any time antibiotics are administered to treat an overgrowth of disease-causing bacteria, the microbiome is also affected. Decreasing relative abundance of the genital or urinary microbiome can lead to recurrent urinary tract infections and  yeast infections  in the vagina. Lactobacilli typically prevent overgrowth of Candida species in the vagina. Chronic antibiotic use can lead to the formation of  antibiotic-resistant  organisms and contribute to the incidence of polymicrobial urinary tract infections.


The  superior fascia of the urogenital diaphragm  is continuous with the  obturator fascia  and stretches across the  pubic arch .


If the obturator fascia be traced medially after leaving the  obturator internus muscle , it will be found attached by some of its deeper or anterior fibers to the inner margin of the  pubic arch , while its superficial or posterior fibers pass over this attachment to become continuous with the superior fascia of the  urogenital diaphragm .


Behind, this layer of the fascia is continuous with the inferior fascia and with the  fascia of Colles ; in front it is continuous with the fascial sheath of the  prostate , and is fused with the inferior fascia to form the  transverse ligament of the pelvis .


Some sources dispute that this structure exists. [ 1 ]  However, whether this layer is real or imagined, it still serves to describe a division of the contents of the perineum in many modern anatomy resources.


This article incorporates text in the  public domain  from  page 429  of the 20th edition of   Gray's Anatomy   (1918)


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The  acrosome  is an  organelle  that develops over the  anterior  (front) half of the head in the  spermatozoa  (sperm cells) of humans and many other animals. It is a cap-like structure derived from the  Golgi apparatus . In  placental mammals , the acrosome contains degradative  enzymes  (including  hyaluronidase  and  acrosin ). [ 1 ]  These enzymes break down the outer membrane of the  ovum , [ 2 ]  called the  zona pellucida , allowing the  haploid   nucleus  in the sperm cell to join with the haploid nucleus in the ovum.
This shedding of the acrosome, known as the  acrosome reaction , can be stimulated  in vitro  by substances that a sperm cell may encounter naturally, such as  progesterone [ 3 ]  or  follicular fluid , as well as the more commonly used calcium  ionophore  A23187. [ 4 ]   This can be done to serve as a positive control when assessing the acrosome reaction of a sperm sample by  flow cytometry [ 5 ]  or  fluorescence microscopy . This is usually done after staining with a fluoresceinated  lectin  such as FITC-PNA, FITC-PSA, FITC-ConA, or fluoresceinated antibody such as FITC-CD46. [ 6 ]


In the case of  globozoospermia  (sperm with round heads), the  Golgi apparatus  is not transformed into the  acrosome , causing  male infertility . [ 7 ]


The  ampulla pulla of vas deferens , also called the  ampulla pulla of ductus deferens , is an enlargement  of the  vas deferens  at the  pulla fundus of the   bladder  which acts as a reservoir for sperm. This structure is seen in some  mammalian  and  squamate  species and is sometimes tortuous in shape.


The  appendix testis  (or  hydatid of Morgagni ) is a  vestigial  remnant of the  Müllerian duct , present on the upper pole of the  testis  and attached to the  tunica vaginalis . It is present about 90% of the time. [ citation needed ]


The appendix of testis can occasionally become twisted, causing acute one-sided testicular pain and may require surgical excision to achieve relief. One third of patients present with a palpable "blue dot" discoloration on the scrotum.  This is nearly diagnostic of this condition. If clinical suspicion is high for the serious  differential diagnosis  of testicular torsion, a surgical exploration of the scrotum is warranted. Torsion of the appendix of testis occurs at ages 0–15 years, with a mean at 10 years, which is similar to that of testicular torsion. [ 1 ]


The  appendix of the epididymis  (or  pedunculated hydatid ) is a small stalked appendage (sometimes duplicated) on the head of the  epididymis . It is usually regarded as a detached  efferent duct .


This structure is derived from the  Wolffian duct  (mesonephric duct) as opposed to the  appendix testis  which is derived from the  Müllerian duct  (paramesonephric duct) remnant.


This article incorporates text in the  public domain  from  page 1242  of the 20th edition of   Gray's Anatomy   (1918)


Blennorrhea  is  mucous  discharge, especially from the  urethra  or  vagina  (that is, mucus  vaginal discharge ). [ 1 ] Blennorrhagia  is an excess of such discharge, [ 2 ]  often specifically referring to that seen in  gonorrhea .


This  women's health  related article is a  stub . You can help Wikipedia by  expanding it .


The  body  or  shaft of the penis  is the free portion of the  human penis  that is located outside of the  pelvic cavity . [ 1 ]  It is the continuation of the internal  root , which is embedded in the  pelvis  and extends to the  glans . [ 2 ]  It is made up of the two  corpora cavernosa  and the  corpus spongiosum  on the underside. The corpora cavernosa are intimately bound to one another with a dorsally fenestrated  septum , which becomes a complete one before the  penile crura . [ 3 ]  The body of the penis is  homologous  to the female  clitoral body . [ 4 ] [ 5 ] [ 6 ]


The body of the penis is suspended from the  pubic symphysis . [ 7 ]  It has two surfaces; the  dorsal  and the  ventral  or  urethral . The  penile raphe  runs on its ventral surface.


The body is surrounded by a bi-layered model of  tunica albuginea  in which a distal ligament buttresses the glans penis and plays an integral role to the penile fibroskeleton, and the structure is called "os analog", a term coined by  Geng Long Hsu  in the Encyclopedia of Reproduction. [ 3 ]  This indispensable structure is a continuation of the body of the human penis, differing from other mammalian penises, in that it has no  baculum  (or erectile bone) and instead relies exclusively on engorgement with blood to reach its  erect state . It is a remnant of the baculum that evolved likely due to change in mating practice. [ 8 ]


A shallow groove, which marks their junction on the upper surface lodges the  deep dorsal vein of the penis , which is flanked by a pair of cavernosal veins of the penis, [ 3 ]  while a deeper and wider groove between them on the surface below contains the corpus spongiosum. The body is ensheathed by  fascia , which includes tunica albuginea,  Buck's fascia ,  dermis , and skin.


This article incorporates text in the  public domain  from  page 1249  of the 20th edition of   Gray's Anatomy   (1918)


The  Bowman–Heidenhain hypothesis  is an early explanation of  renal function  and  urinary   secretion .


The hypothesis states that the  kidney  is first and foremost a secreting  gland . According to the theory,  glomeruli  are merely filters, while the  tubules  are the true secretory structures. [ 1 ]  To prove his  hypothesis , Rudolph Heidenhain injected  methylene blue  into an animal's  bloodstream , which soon appeared in the  urine . More evident proof of this theory is that when the tubules are destroyed, urine becomes watery and  urea  and other toxic products remain in the  blood . [ 2 ]


This theory was later merged with the  Ludwig theory  to form the modern theory. [ 3 ]


The  bulb of penis  is the proximal/posterior bulged [ 1 ]  end of the (unpaired median)  corpus spongiosum penis . Together with the two  crura  (one crus on each side of the bulb), it constitutes the  root of the penis . [ 2 ]  It is covered by the  bulbospongiosus .


Proximally/posteriorly, the bulb of penis extends towards the  perineal body . The bulb exhibits a slight yet palpable midline notch upon its inferior aspect. [ 2 ]


The male urethra enters the penis at the superior aspect of the anterior part of the bulb (most of the bulb is thus situated inferoposteriorly to the urethra), and the  arteries of bulb of penis  enter near the urethra. [ 2 ]


The bulb of penis is  homologous  to the  vestibular bulbs  in females. [ 3 ]


Cavernous tissue  refers to  blood -filled spaces lined by  endothelium  and surrounded by  smooth muscle . It is present in the  erectile tissue  of the  penis  and  clitoris . [ 1 ]


This  cardiovascular system  article is a  stub . You can help Wikipedia by  expanding it .


Cephalopelvic disproportion (CPD)  exists when the capacity of the  pelvis  is inadequate to allow the  fetus  to negotiate the  birth canal . This may be due to a small pelvis, a nongynecoid pelvic formation, a large fetus, an unfavorable orientation of the fetus, or a combination of these factors. Certain medical conditions may distort pelvic bones, such as  rickets  or a pelvic  fracture , and lead to CPD.


Transverse diagonal measurement has been proposed as a predictive method. [ 1 ]


1.	Prolonged Labor: Labor that doesn’t progress as expected, particularly during the active phase.


2.	Failure to Progress: Lack of dilation or descent of the baby despite strong contractions.


3.	Severe Pain: Intense pain that is disproportionate to normal labor pain.


4.	Fetal Distress: Signs like abnormal heart rate patterns detected via fetal monitoring.


5.	Maternal Exhaustion: Extreme fatigue in the mother due to prolonged labor.


6.	High Station: The baby’s head remains high in the pelvis and doesn’t descend despite strong contractions.


Diagnosis of CPD usually occurs during labor, often requiring medical interventions such as a cesarean section (C-section) to ensure the safety of both mother and baby.


A large fetus can be one cause of CPD. A large fetus can be caused by  gestational diabetes ,  postterm pregnancy , genetic factors, and  multiparity . [ citation needed ]


The shape of the pelvis can also be a cause of CPD. The pelvis may be too small, or the shape of the pelvis may be malformed. [ 2 ]  Shorter women are more likely to have CPD [ 1 ]  as are adolescents. [ 3 ]


Diagnosis of CPD may be made when there is  failure to progress , but not all cases of prolonged labour are the result of CPD. Use of ultrasound to measure the size of the fetus in the womb is controversial, as these methods are often inaccurate and may lead to unnecessary  caesarian section ; a trial of labour is often recommended even if size of the fetus is estimated to be large. [ 2 ]


Theoretically,  pelvimetry  may identify cephalo-pelvic disproportion. However, a woman's pelvis loosens up before birth (with the help of hormones). A  Cochrane review  in 2017 found that there was too little evidence to show whether pelvimetry is beneficial and safe when the baby is in  cephalic presentation . [ 4 ]  A review in 2003 came to the conclusion that pelvimetry does not change the management of pregnant women, and recommended that all women should be allowed a trial of labor regardless of pelvimetry results. [ 5 ]  It considered routine performance of pelvimetry to be a waste of time, a potential liability, and an unnecessary discomfort. [ 5 ]


In the case of a fetus being too large, some obstetricians recommend  induction of labour  for earlier delivery. Diagnosis of CPD in active labour will usually result in a  Caesarian section. [ citation needed ]


Chyloderma  is swelling of the  scrotum  resulting from chronic  lymphatic  obstruction. [ 1 ]  Obstruction may be caused by a  nematode  such as  Wuchereria bancrofti . This condition is also known as  lymphscrotum  or  elephantiasis scroti .


The  corona of glans penis  (or, directly from the  Latin , the  corona glandis penis [ 1 ] ) or  penis crown  refers to the rounded projecting border or flare that forms at the base of the  glans  in  human males . The corona overhangs a  mucosal  surface, known as the neck of the  penis , which separates the shaft and the glans. [ 2 ]  The deep retro-glandular coronal  sulcus  forms between the corona and the neck of the penis. The two sides of the corona merge on the ventral midline forming the  septum glandis . [ 3 ]  The circumference of the corona is richly  innervated  and is described as a highly erogenous area of the glans. [ 4 ]


During the  embryonic  development of the male fetus, a thickening on the  epidermis  appears around the base of the developing glans. [ 5 ]  The thickening separates from the glans creating the preputial fold and the preputial lamina on its ventral surface. [ 6 ]  The lamina expands outwards over the  epithelium  of the glans and also backwards forming an ingrowing fold at the base of the glans that will become the coronal sulcus. [ 7 ]


The corona and the neck are highly  vascularized  areas of the penis. The axial and  dorsal penile arteries  merge together at the neck before entering the glans. [ 8 ]  Branches of the dorsal artery of the penis curve around the distal shaft to enter the  frenulum  and the glans from its ventral surface. [ 9 ]  Small venous tributaries deriving from the corona drain the glans forming a venous retro-coronal  plexus  before merging with the  dorsal veins . [ 8 ]


The circumference and the underside of the corona are densely innervated by several types of  nerve  terminals, including  genital corpuscles  and  free nerve endings , and are considered by males a highly  erogenous zone  of their penis. [ 4 ] [ 10 ]  The area is reported to be particularly responsive to  stimulation  and a source of distinct sexual pleasure. [ 11 ] [ 12 ]


In some males, small skin-colored bumps, known as  pearly penile papules , may appear at the circumference of the corona. Their appearance may vary from being hardly noticeable in some men to more prominent and well-defined in others. The papules are painless, harmless and non-sexually transmitted. They usually appear in late puberty and are thought to disappear with age. [ 13 ]  Even though they do not require treatment, they can easily be removed, especially for aesthetic purposes. [ 14 ]


A  cortical lobule  (or  renal lobule ) is a part of a  renal lobe . It consists of the  nephrons  grouped around a single  medullary ray , and draining into a single  collecting duct . Its near identical parallel is the  rectal   lobe [ citation needed ] , which is present in the majority of mammals.


The  cremasteric fascia  is a  fascia  in the  scrotum . As the  cremaster  descends, it forms a series of loops which differ in thickness and length in different subjects. At the upper part of the cord the loops are short, but they become in succession longer and longer, the longest reaching down as low as the  testis , where a few are inserted into the  tunica vaginalis . These loops are united together by  areolar tissue , and form a thin covering over the cord and testis, the cremasteric fascia.


The cremasteric fascia lies between the more superficial  external spermatic fascia  and the deeper  internal spermatic fascia . [ 1 ]  It is a continuation of the  aponeurosis  of the  abdominal internal oblique muscle . [ 2 ] [ 3 ]


This article incorporates text in the  public domain  from  page 414  of the 20th edition of   Gray's Anatomy   (1918)


This  muscle  article is a  stub . You can help Wikipedia by  expanding it .


Crossed dystopia  (also  unilateral fusion cross fused renal ectopia ) is a rare form of  renal ectopia  ( kidney  displacement) where both kidneys are on the same side of the  spine . [ 1 ]  In many cases, the two kidneys are fused together, yet retain their own  vessels  and  ureters . [ 2 ]  The ureter of the lower kidney crosses the midline to enter the  bladder  on the contralateral side. Both  renal pelves  can lie one above each other medial to the  renal parenchyma  (unilateral long kidney) or the pelvis of the crossed kidney faces laterally (unilateral S-shaped kidney).  Urogram  is diagnostic.


The anomaly can be diagnosed through ultrasound or  urography , but surgical intervention is only necessary if there are other complications, such as  tumors  or  pyelonephritis . [ citation needed ]


The  dorsal nerve of the clitoris  is a  nerve  in females that branches off the  pudendal nerve [ 1 ]  to innervate the  clitoris . The nerve is important for female sexual pleasure, [ 2 ]  and it may play a role in  clitoral erections . [ 3 ]


It travels from below the  inferior pubic ramus [ 4 ]  to the  suspensory ligament of the clitoris . At its thickest, the DNC is 2 mm (0.079 in) in diameter, visible to the naked eye during dissection. [ 2 ]  The DNC splits into two nerve branches on either side of the midline, closely following the crura of the clitoris. [ 3 ]


Some surgeries—for example, sling surgeries to treat female urinary incontinence—can damage the DNC, causing a loss of sensation in the clitoris. Understanding the nerve is important for urologists and gynecologists who may operate on organs near the DNC. [ 2 ] [ 4 ] [ 5 ]


The dorsal nerve of the clitoris is analogous to the  dorsal nerve of the penis  in males. [ 6 ]   It is a terminal branch of the  pudendal nerve . [ 1 ]


This  neuroanatomy  article is a  stub . You can help Wikipedia by  expanding it .


The  epoöphoron  lies in the  mesosalpinx  between the  ovary  and the  uterine tube , and consists of a few short tubules, the  ductuli transversi  which converge toward the ovary while their opposite ends open into a rudimentary duct, the ductus longitudinalis epoöphori ( duct of Gartner ).


The ductuli transversi of the epoophoron is a remnant of the tubules of the  Wolffian body  or mesonephros.


This article incorporates text in the  public domain  from  page 1255  of the 20th edition of   Gray's Anatomy   (1918)


Ectopic kidney  describes a  kidney  that is not located in its usual position ( ectopia ). This condition results from the kidney failing to ascend from its origin in the  true pelvis  or from a superiorly ascended kidney located in the  thorax . [ 1 ]


It has an incidence of approximately 1/900. [ 2 ]


Ejaculation disorders  are the most common sexual dysfunction in men. [ 1 ]  Common ejaculatory disorders include:  premature ejaculation ,  retrograde ejaculation ,  delayed ejaculation ,  anejaculation ,  inhibited ejaculation , and  anorgasmia . [ 2 ]


The  external spermatic fascia  ( intercrural  or  intercolumnar fascia ) is a thin membrane, prolonged downward around the surface of the  spermatic cord  and  testis . It is separated from the  dartos tunic  by  loose areolar tissue . It is occasionally referred to as 'Le Fascia de Webster' after an anatomist who once described it.


The external spermatic fascia is derived from the  aponeurosis  of the  abdominal external oblique muscle . [ 1 ] [ 2 ]  It is acquired by the  spermatic cord  at the  superficial inguinal ring . [ 1 ]


This article incorporates text in the  public domain  from  page 1238  of the 20th edition of   Gray's Anatomy   (1918)


The  external sphincter muscle of the female urethra  is a muscle which controls  urination  in females. The muscle fibers arise on either side from the margin of the inferior ramus of the pubis. They are directed across the pubic arch in front of the urethra, and pass around it to blend with the muscular fibers of the opposite side, between the urethra and vagina.


The term "urethrovaginal sphincter" ("sphincter urethrovaginalis") is sometimes used to describe the component adjacent to the  vagina . [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ]


The "compressor urethrae" is also considered a distinct, adjacent muscle by some sources, [ 6 ] [ 7 ] [ 8 ] [ 9 ]


The muscle helps maintain  continence  of  urine  along with the  internal urethral sphincter  which is under control of the  autonomic nervous system . The external sphincter muscle prevents urine leakage as the muscle is tonically contracted via  somatic  fibers that originate in  Onuf's nucleus  and pass through  sacral spinal nerves  S2-S4 then the  pudendal nerve  to  synapse  on the muscle. [ 7 ] [ 10 ]


Voiding urine begins with voluntary relaxation of the external urethral sphincter. This is facilitated by inhibition of the somatic neurons in Onuf's nucleus via signals arising in the  pontine micturition center  and traveling through the  descending reticulospinal tracts .


This article incorporates text in the  public domain  from  page 431  of the 20th edition of   Gray's Anatomy   (1918)


The  external sphincter muscle of the male urethra , also  sphincter urethrae membranaceae ,  sphincter urethrae externus , surrounds the whole length of the  membranous urethra , and is enclosed in the  fascia  of the  urogenital diaphragm .


Its external fibers arise from the junction of the  inferior pubic ramus  and  ischium  to the extent of 1.25 to 2 cm., and from the neighboring fascia.


They arch across the front of the urethra and  bulbourethral  glands, pass around the urethra, and behind it unite with the muscle of the opposite side, by means of a tendinous  raphe .


Its innermost fibers form a continuous circular investment for the membranous urethra.


The muscle helps maintain  continence  of  urine  along with the  internal urethral sphincter  which is under control of the  autonomic nervous system . The external sphincter muscle prevents urine leakage as the muscle is tonically contracted via  somatic  fibers that originate in  Onuf's nucleus  and pass through  sacral spinal nerves  S2-S4 then the  pudendal nerve  to  synapse  on the muscle. [ 1 ] [ 2 ]


Voiding urine begins with voluntary relaxation of the external urethral sphincter. This is facilitated by inhibition of the somatic neurons in Onuf's nucleus via signals arising in the  pontine micturition center  and traveling through the  descending reticulospinal tracts . During ejaculation, the external sphincter opens and the internal sphincter closes. [ 3 ]


Facet cells  (also known as  umbrella cells , [ 1 ]  capping cells, superficial urotheliocytes) are a type of cells located in the  renal pelvis , the  ureters , and the  urethra . Umbrella cells form the outermost layer of the  urothelium , which is a special type of  epithelium  found in the  renal pelvis , the  ureters , and the  urethra . Umbrella cells are special in that they can contain  multiple nuclei . Their  apical membrane  contains numerous  invaginations , which allows the cells to stretch during  urination . Umbrella cells are linked together with tight  junctions  which:


Umbrella cells contain  uroplakin ia ,  uroplakin ib , uroplakin ii, and uroplakin iii. [ 3 ]  These increase the strength of the  urothelium . [ 3 ]


In renal physiology, the  filtration fraction  is the ratio of the  glomerular filtration rate  (GFR) over the  renal plasma flow  (RPF).


Filtration Fraction, FF = GFR/RPF, or

 F
 F
 =

 G
 F
 R

 R
 P
 F

 {\displaystyle FF={\frac {GFR}{RPF}}}

 .


The filtration fraction, therefore, represents the proportion of the fluid reaching the  kidneys  that passes into the  renal tubules .  It is normally about 20%.


GFR on its own is the most common and important measure of  renal function . However, in conditions such as  renal artery stenosis ,  blood flow  to the kidneys is reduced. Filtration fraction must therefore be increased in order to perform the normal functions of the kidney.  Loop diuretics  and  thiazide diuretics  decrease filtration fraction.


Catecholamines  ( norepinephrine  and  epinephrine ) increase filtration fraction by  vasoconstriction  of  afferent  and  efferent arterioles , possibly through activation of  alpha-1 adrenergic receptors .


Severe  hemorrhage  will also result in an increased filtration fraction.


The  follicular antrum  is the portion of an  ovarian follicle  filled with  follicular fluid . Appearance of the follicular antrum during follicular maturation is the first sign that a follicle has reached the next stage of maturation. It has changed from a primary follicle to a secondary follicle.


Follicular fluid  is a liquid which fills the  follicular antrum  and surrounds the  oocyte  in an  ovarian follicle .  This fluid is rich in  hyaluronic acid , and is used in a modified  intracytoplasmic sperm injection  (ICSI) called  physiological ICSI  (PICSI), semi-viscous and yellow in colour. [ 1 ]  Its components come mainly from  granulosa cells . [ 2 ]


The  fossa of vestibule of vagina  (or  fossa navicularis ) is a boat-shaped depression between the  vaginal opening / hymen  and the  frenulum labiorum pudendi  within the  vestibule . The small openings of the  Bartholin's ducts  can be seen in the grooves between the hymen and the  labia minora , on either side.


This article incorporates text in the  public domain  from  page 1323  of the 20th edition of   Gray's Anatomy   (1918)


The  frenulum of labia minora  ( fourchette  or  posterior commissure of the labia minora ) is a  frenulum  where the  labia minora  meet  posteriorly . [ 1 ]


The fourchette may be torn during  delivery  due to the sudden stretching of the  vulval  orifice, or during copulation.  To prevent this tearing in a haphazard manner,  obstetricians  and, less frequently,  midwives  may perform an  episiotomy , which is a deliberate cut made in the  perineum  starting from the fourchette and continuing back along the perineum toward the anus. Sometimes this surgical cut may extend to involve the perineal body and thus reduce anal sphincter function. Thus some obstetricians have opted to perform a posterior-lateral cut in the perineum to prevent this potential complication from occurring.


The fourchette may also be torn in acts of violence wherein forced entry occurs such as  rape . When the fourchette is torn, the bleeding which ensues sometimes requires surgical  suturing  for containment.


The fourchette is named with the  French  word for " fork " or " wishbone ", owing to its shape. (See  frenulum  for its etymology.)


The  fundiform ligament of the penis  is a structure of the external genitalia whose descriptions differ according to the source consulted. [ 1 ]


The 41st Edition of  Gray's Anatomy  (2015) and  Traité d'Anatomie humaine  do not acknowledge this structure. Some sources equate the fundiform ligament with the  Scarpa fascia . [ 1 ]


According to the  Medical Dictionary of the French Academy of Medicine  the fundiform ligament is a bilaterally paired bundle of fibres of the lateral lamina of the  suspensory ligament of penis  which curve around the lateral and inferior aspects of the penis to unite with the contralateral fundiform ligament beneath the urethral aspect of the penis; the two fundiform ligaments thus form a sling which offers structural support to the penis. [ 2 ]


Although rarely mentioned, this ligament is also found in females (at the  clitoris ). [ citation needed ]


A 2023 cadaveric study on 7 cadavers characterised the fundiform ligament as a structurally heterogenous structure that is superficial to the suspensory ligament of penis. The study identified three morphological types/variants of the fundiform ligament: a single triangular structure (attached proximally onto the linea alba); a doubled structure with accessory bundles (one medial main band and one lateral accessory band on each side); and an amourphous, ligamentous fibrous connective band structure. [ 1 ]


Gartner's duct , also known as  Gartner's canal  or the  ductus longitudinalis epoophori , is a potential  embryological  remnant in human female development of the  mesonephric duct  in the  development of the urinary and reproductive organs . [ 2 ]  It was discovered and described in 1822 by  Hermann Treschow Gartner .


Gartner's duct is located in the  uterus '  broad ligament . Its position is parallel with the lateral  uterine tube  and lateral walls of  vagina  and  cervix .


The paired mesonephric ducts in the  male , in contrast, go on to form the paired  epididymides ,  vasa deferentia ,  ejaculatory ducts  and  seminal vesicles .


In  females , they may persist between the layer of the  broad ligament of the uterus  and in the wall of the  vagina . [ citation needed ]


These may give rise to  Gartner's duct cysts . [ 3 ]


Genitourinary amoebiasis  or  renal amoebiasis  is a rare complication to  amoebic liver abscess , which in turn is a complication of  amoebiasis . It is believed to result from liver abscesses breaking open, whereupon the amoebas spread  through the blood  to the new locale. Genital involvement is thought to result from  fistula  formation from the liver or through  rectocolitis . The involvement causes lesions which exude a high degree of pus. [ 1 ]


The  germinal epithelium  is the  epithelial  layer of the  seminiferous tubules  of the  testicles . It is also known as the wall of the seminiferous tubules. The cells in the epithelium are connected via tight junctions.


There are two types of cells in the germinal epithelium. The large  Sertoli cells  (not dividing) function as supportive cells to the developing  sperm . The second cell type is the cells belonging to the  spermatogenic  cell lineage. These eventually develop into sperm cells ( spermatozoon ). Typically, the spermatogenic cells will make four to eight layers in the germinal epithelium. [ 1 ]


Gouverneur's syndrome  is characterised by  vesicointestinal fistula  with associated  suprapubic  pain, urinary frequency, pain on passing urine, and  tenesmus . [ 1 ] [ 2 ]  It is named after French physician R. Gouverneur. [ 3 ]


The  holonephros  is the  kidney  of the  larvae  of  cyclostomes  and the  Gymnophiona . The entire mass of nephrogenic tissue gives rise to this kidney, which is usually of simple form with a single  tubule  in each segment.


In  medicine ,  hyperspermia  is a condition in which a  male  has an abnormally large amount of  semen  or  ejaculate   volume [ 1 ]  and is generally defined when the ejaculate is above 6 mL. [ 2 ]  It is the opposite of  hypospermia , which is defined as a semen volume of less than 1.5 mL.


Hyperspermia alone does not appear to influence sperm health. However, large volumes of ejaculate may have lower concentrations of sperm, leading to low fertility. [ 3 ] [ 1 ]


In some cases, high semen volumes can be a symptom of  male accessory gland infection . [ 4 ]


The  internal spermatic fascia  ( infundibuliform fascia  or  Le deuxième fascia de Webster ) is a thin layer, which loosely invests the  spermatic cord .


The internal spermatic fascia is derived from the  transversalis fascia . [ 1 ] [ 2 ]  It is acquired by the  spermatic cord  at the  deep inguinal ring . [ 1 ]  It has very little  lymphatic drainage . [ 3 ]  It is mainly supplied by sensory afferents and the  sympathetic nervous system . [ 3 ]


This article incorporates text in the  public domain  from  page 1239  of the 20th edition of   Gray's Anatomy   (1918)


The  internal urethral orifice  is the opening of the  urinary bladder  into the  urethra . [ 1 ]


It is usually somewhat crescent-shaped. [ citation needed ]


It is formed by the  neck of the urinary bladder . It opens at the apex/inferior angle of the  trigone of the bladder , some 2-3 cm anteromedial to either  ureteral orifice . [ 1 ]


The  mucous membrane  immediately posterior to it presents a slight elevation in males - the  uvula vesicae  - caused by the middle lobe of the  prostate . [ citation needed ]


This article incorporates text in the  public domain  from  page 1232  of the 20th edition of   Gray's Anatomy   (1918)


Juxtaglomerular cells  ( JG cells ), also known as  juxtaglomerular granular cells  are  cells  in the  kidney  that synthesize, store, and secrete the enzyme  renin . [ 1 ]  They are specialized  smooth muscle cells  mainly in the walls of the  afferent arterioles  (and some in the  efferent arterioles ) [ citation needed ]  that deliver blood to the  glomerulus . In synthesizing renin, they play a critical role in the  renin–angiotensin system  and thus in  autoregulation  of the kidney.


Juxtaglomerular cells secrete renin in response to a drop in pressure detected by  stretch receptors  in the vascular walls, or when stimulated by  macula densa  cells. Macula densa cells are located in the distal convoluted tubule, and stimulate juxtaglomerular cells to release renin when they detect a drop in chloride concentration in  tubular fluid . Together, juxtaglomerular cells, extraglomerular mesangial cells and macula densa cells comprise the  juxtaglomerular apparatus .


In appropriately stained tissue sections, juxtaglomerular cells are distinguished by their granulated cytoplasm.


The juxtaglomerular cell is a cell that is located near the glomerulus, hence its name.


Similar to cardiac tissue, juxtaglomerular cells harbor  β1 adrenergic receptors . When stimulated by  epinephrine  or  norepinephrine , these receptors induce the secretion of renin. These cells also respond directly to a decrease in systemic blood pressure which is manifested as a lower renal perfusion pressure.


The  Kokko and Rector model  is a theory explaining the mechanism of generation of a gradient in the  inner medulla  of the  kidney . Unlike earlier theories explaining the mechanism using counter current mechanism (as is the case in the  outer medulla ), the driving force for salt reabsorption is stated to be urea accumulation. It has been proved that counter current mechanism cannot be the case in the  inner medulla , since there are no salt pumps, and the  cell membrane  is too  permeable  to salt. [ clarification needed ]


It has been proposed by Juha Kokko and Floyd Rector Jr. in 1972. [ 1 ]


Lacunae of Morgagni , also called the  urethral  lacunae of the male urethra ( lacunae urethralis ,  urethrae masculinae  or the  crypts of Morgagni ), are small depressions or recesses on the surface of the mucous membrane of the urethra. Their openings are usually directed  distally . The largest of these recesses is called  lacuna magna  (or the  sinus of Guérin , or  Guérin's sinus ), which is situated on the upper surface of the  fossa navicularis .


Located deeper within the lacunae are branching mucous  tubules  called the  glands of Littre . The lacunae of Morgagni are named after Italian  anatomist   Giovanni Battista Morgagni  (1682–1771).


The  medulla of ovary  (or  Zona vasculosa of Waldeyer ) is a highly vascular stroma in the center of the  ovary .  It forms from embryonic  mesenchyme  and contains blood vessels, lymphatic vessels, and nerves.


This stroma forms the tissue of the  hilum  by which the  ovarian ligament  is attached, and through which the blood vessels enter: it does not contain any  ovarian follicles .


This article incorporates text in the  public domain  from  page 1256  of the 20th edition of   Gray's Anatomy   (1918)


In anatomy, a  medullary ray   ( Ferrein's pyramid ) is the middle part of a  cortical lobule  (or renal lobule). Each consists of a group of  nephrons  in the  renal cortex . [ 1 ]  Their name is potentially misleading, as "medullary" refers to their destination, not their location. They travel perpendicular to the capsule, and extend from the cortex to the medulla. They may be visualised during  urography . [ 1 ]


Megaureter  is a medical anomaly whereby the  ureter  is abnormally  dilated .  Congenital  megaureter is an uncommon condition which is more common in males, may be bilateral, and is often associated with other congenital anomalies. The cause is thought to be  aperistalsis  of the distal ureter, leading to dilatation.  [ citation needed ]


The  cutoff  value for megaureter is when it is wider than 6 [ 1 ]  or 7 mm. [ 2 ]


A functional obstruction at the lower end of the ureter leads to progressive dilatation and a tendency to  infection . The ureteric orifice appears normal and a ureteric  catheter  passes easily. [ citation needed ]


Definitive  surgical treatment  involves refashioning the lower end of the affected ureter so that a tunnelled reimplantation into the  bladder  can be done to prevent reflux. [ citation needed ]


The larger  ovarian follicles  consist of an external fibrovascular coat, connected with the surrounding  stroma of the ovary  by a network of blood vessels, and an internal coat, which consists of several layers of nucleated cells, called the  membrana granulosa . It contains numerous  granulosa cells .


At one part of the mature follicle the cells of the membrana granulosa are collected into a mass which projects into the cavity of the follicle. This is termed the  discus proligerus .


The  mesometrium  is the  mesentery  of the  uterus . It constitutes the majority of the  broad ligament of the uterus , [ 1 ]  excluding only the portions adjacent to the  uterine tube  (the mesosalpinx) and  ovary  (the  mesovarium ).


It is adjacent to the  mesosalpinx .


The  ureter  is among the structures found in the mesometrium.


This  ligament -related article is a  stub . You can help Wikipedia by  expanding it .


The  mesosalpinx  is part of the lining of the  abdominal cavity  in  higher vertebrates , specifically the portion of the  broad ligament  that stretches from the  ovary  to the level of the  fallopian tube .


This article incorporates text in the  public domain  from  page 1261  of the 20th edition of   Gray's Anatomy   (1918)


The  mesovarium  is the portion of the  broad ligament  of the  uterus  that suspends the  ovaries . The ovary is not covered by the mesovarium; rather, it is covered by germinal epithelium.


At first, the  mesonephros  and  genital ridge  are suspended by a common  mesentery , but as the  embryo  grows the genital ridge gradually becomes pinched off from the mesonephros, with which it is at first continuous, though it still remains connected to the remnant of this body by a fold of  peritoneum . In the male, this is the  mesorchium , and in the female, this is the mesovarium.


Minimal mesangial glomerulonephritis  is a type of  glomerulonephritis  that is seen in 10% to 25% of  SLE  cases and is associated with mild clinical  symptoms .  Immune complexes  deposit in the  mesangium , with a slight increase in the  mesangial matrix  and  cellularity . [ 1 ]


Necrospermia  (or  necrozoospermia ) is a condition in which there is a low percentage of live and a very high percentage of immotile  spermatozoa  in  semen . [ 1 ]


Necrospermia is usually confused with asthenozoospermia, which is the inability of the sperm to move even when alive. To check for necrospermia, samples with a high percentage of immobile sperm are stained to check for vitality. If they are dead sperm they will be stained, as the membrane is broken and the dye enters indiscriminately. Necrozoospermia is a rare condition with a reported prevalence of 0.2–0.48% in infertile subjects. [ 2 ]


It has been claimed that necrospermia can be successfully treated in  Ayurveda . A single case report to that effect has been published. [ 3 ] [ dubious  –  discuss ]


Nephromegaly  is the process whereby a  kidney  or both kidneys become enlarged. [ 1 ]  Both  autosomal dominant  and  autosomal recessive polycystic kidney disease  can cause nephromegaly. [ citation needed ]


The  ovarian cortex  is the outer portion of the  ovary . The  ovarian follicles  are located within the ovarian cortex. The ovarian cortex is made up of  connective tissue .  [ 1 ]  Ovarian cortex  tissue transplant  has been performed to treat  infertility . [ 2 ] [ 3 ]