query: failure of the testes to descend into the scrotum at birth

pos: Cryptorchidism Cryptorchidism Cryptorchidism is the absence of one or both testes from the scrotum. The word is from the Greek κρυπτός, "kryptos", meaning hidden, and ὄρχις, "orchis", meaning testicle. It is the most common birth defect of the male genital tract. About 3% of full-term and 30% of premature infant boys are born with at least one undescended testis. However, about 80% of cryptorchid testes descend by the first year of life (the majority within three months), making the true incidence of cryptorchidism around 1% overall. Cryptorchidism may develop after infancy, sometimes as late as young adulthood, but that is exceptional.

pos: Testicle fetal abdomen to the inguinal ring and beyond to the inguinal canal and into the scrotum. In most cases (97% full-term, 70% preterm), both testes have descended by birth. In most other cases, only one testis fails to descend (cryptorchidism) and that will probably express itself within a year. The testes grow in response to the start of spermatogenesis. Size depends on lytic function, sperm production (amount of spermatogenesis present in testis), interstitial fluid, and Sertoli cell fluid production. After puberty, the volume of the testes can be increased by over 500% as compared to the pre-pubertal size. Testicles are

pos: Cryptorchidism of testicular germ-cell tumors, and psychological problems when the boy is grown. Undescended testes are also more susceptible to testicular torsion (and subsequent infarction) and inguinal hernias. Without intervention, an undescended testicle will usually descend during the first year of life, but to reduce these risks, undescended testes can be brought into the scrotum in infancy by a surgical procedure called an orchiopexy. Although cryptorchidism nearly always refers to congenital absence or maldescent, a testis observed in the scrotum in early infancy can occasionally "reascend" (move back up) into the inguinal canal. A testis which can readily move or be

pos: Glycerol kinase deficiency disabilities, and myopathy, tend to have an added psychological effect on the subject due to the fact that they can set him or her apart from those without GKD. Cryptorchidism, the failure of one or both of the testes to descend to the scrotum, has been known to lead to sexual identity confusion amongst young boys because it is such a major physiological anomaly. Strabismus is the misalignment of one’s eyes. Typically, one is focused but the other is “lazy” and is directed inward or out ward (up and down is less common but does occur). Treatments for Glycerol Kinase

pos: Intersex medical interventions these are rare in North America and Europe. Masculinizing surgery for completely virilized individuals with XX sex chromosomes and CAH is even rarer. Orchiopexy for repair of undescended testes (cryptorchidism) is the second most common surgery performed on infant male genitalia (after circumcision). The surgeon moves one or both testes, with blood vessels, from an abdominal or inguinal position to the scrotum. If the inguinal canal is open it must be closed to prevent hernia. Potential surgical problems include maintaining the blood supply. If vessels cannot be stretched into the scrotum, or are separated and cannot be reconnected, a testis

pos: Prostaglandin DP1 receptor pulmonary vein relaxation in part by acting through DP1 in insolated human pulmonary vascular preparations; and that the effect of treprostinil on DP1 in human pulmonary veins may contribute to its therapeutic efficacy in primary pulmonary hypertension. Studies in male mice indicate that DP1 activation induces the translocation of SOX9 into the nucleus thereby signaling for the maturation of Sertoli cells and embryonic gonads. Disruption of this DP1-activated circuit leads to disordered maturation of the male reproductive organs such as Cryptorchidism (i.e. failure of testes descent into the scrotum) in mice and, it is suggested, may also do so in

pos: Opitz G/BBB syndrome laryngeal cleft; which can allow food or fluid to enter the airway and make breathing and eating a difficult task. Genital abnormalities like a urinary opening under the penis (hypospadias), undescended testes (cryptorchidism), underdeveloped scrotum and a scrotum divided into two lobes (bifid scrotum) can all be commonplace for males with the disease. Developmental delays of the brain and nervous system are also common in both types I and II of the disease. 50% of people with Opitz G/BBB Syndrome will experience developmental delay and mild intellectual disability. This can impact motor skills, speech and learning capabilities. Some of these

pos: Cryptorchidism inguinal testicle. Testicular tumors and testicular torsion are rare in cryptorchid cats, but castration is usually performed due to unwanted behavior such as urine spraying. In horses, cryptorchidism is sufficiently common that affected males (ridglings) are routinely gelded. Rarely, cryptorchidism is due to the presence of a congenital testicular tumor such as a teratoma, which has a tendency to grow large. Cryptorchidism Cryptorchidism is the absence of one or both testes from the scrotum. The word is from the Greek κρυπτός, "kryptos", meaning hidden, and ὄρχις, "orchis", meaning testicle. It is the most common birth defect of the male genital

pos: Partial androgen insensitivity syndrome rare, but have been reported. The gonads in individuals with PAIS are testes, regardless of phenotype; during the embryonic stage of development, testes form in an androgen-independent process that occurs due to the influence of the SRY gene on the Y chromosome. Cryptorchidism is common, and carries with it a 50% risk of germ cell malignancy. If the testes are located intrascrotally, there may still be significant risk of germ cell malignancy; studies have not yet been published to assess this risk. Predominantly male phenotypes vary in the degree of genital undermasculinization to include micropenis, chordee, bifid scrotum, and /

pos: Scrotal ultrasound in undescended testes (Cryptorchidism). Undescended testis is found in 4% of full-term infants but only 0.8% of males at the age of 1 year have true cryptorchidism. Although an undescended testis can be found anywhere along the pathway of descent from the retroperitoneum to the scrotum, the inguinal canal is the most common site for an undescended testis. Deviation of testis from the normal pathway of descent will result in ectopic testis that is commonly seen in pubopenile, femoral triangle and perineal regions. Besides infertility, undescended testes carry an increased risk of malignancy even for the normally located contralateral testis.

pos: Testicular dysgenesis syndrome the scrotum or retreats quickly after being pulled into a higher position. In 30% of cases the testes cannot be felt indicating an intra-abdominal location. The risk factors for Cryptorchidism are: Poor semen quality is measured not only by the number of sperm a man produces but also by how effective the sperm is at fertilising an egg. The motility and shape of the sperm are important for this role. A man with poor semen quality will often present with fertility problems which is defined as a couple trying to conceive for over 1 year with no success. Diagnosis can

pos: Aarskog–Scott syndrome short fingers (brachydactyly), curved pinky fingers (fifth finger clinodactyly), webbing of the skin between some fingers (cutaneous syndactyly), and a single crease across the palm. Other abnormalities in people with Aarskog-Scott syndrome include heart defects and a split in the upper lip (cleft lip) with or without an opening in the roof of the mouth (cleft palate). Most males with Aarskog-Scott syndrome have a shawl scrotum, in which the scrotum surrounds the penis instead of hanging below. Less often, they have undescended testes (cryptorchidism) or a soft out-pouching around the belly-button (umbilical hernia) or in the lower abdomen (inguinal hernia).

pos: Malpuech facial clefting syndrome congenital mislocation of the urinary meatus), cryptorchidism (ectopic or undescended testes), bifid (split) and underdeveloped scrotum, and an obstructive urethral valve. An affected boy was also reported by Reardon et al. (2001) with left renal agenesis, an enlarged and downwardly displaced right kidney, cryptorchidism and a shawl scrotum. Other malformations that have been noted with the syndrome are omphalocele and an umbilical hernia. Congenital abnormalities of the heart have also been observed with Malpuech syndrome. From a healthy Japanese couple, Chinen and Naritomi (1995) described the sixth child who had features consistent with the disorder. This two-month-old male infant was

pos: Testicular dysgenesis syndrome found on the distal end of the penis. It is generally diagnosed at birth from visual confirmation of the hallmark features. As well as an unusual location of the urethra, the prepuce (foreskin) is typically incomplete as well. The abnormal ‘hooded’ prepuce is what often draws attention to the condition but can occur separately to hypospadias. In Cryptorchidism a diagnosis is made from a physical examination which is performed when the baby is lacking one or both testes in the dependant portion of the scrotal sac. 70% of cryptorchid testes can be felt and are unable to be pulled into

pos: Cryptorchidism a simple matter of temperature. Subtle or transient hormone deficiencies or other factors that lead to a lack of descent also may impair the development of spermatogenic tissue. The inhibition of spermatogenesis by ordinary intra-abdominal temperature is so potent that continual suspension of normal testes tightly against the inguinal ring at the top of the scrotum by means of special "suspensory briefs" has been researched as a method of male contraception, and was referred to as "artificial cryptorchidism" by one report. An additional factor contributing to infertility is the high rate of anomalies of the epididymis in boys with cryptorchidism

pos: Pomeranian (dog) skin infections, and reproductive hormone disorders. Another common disorder in male Pomeranians is cryptorchidism. This is when either one or both of the testicles do not descend into the scrotum. It is treated through surgical removal of the retained testicle. The Pomeranian is a small but energetic breed of dog. Although Pomeranians benefit from frequent attention, they need relatively little exercise: it is recommended to take them on several daily walks and let them run around an enclosed space. The forerunners of today's Pomeranian breed were large working dogs from the Arctic regions. These dogs are commonly known as the

neg: Cryptorchidism (over 90% in some studies). Even after orchiopexy, these may also affect sperm maturation and motility at an older age. The most common diagnostic dilemma in otherwise normal boys is distinguishing a retractile testis from a testis that will not descend spontaneously into the scrotum. Retractile testes are more common than truly undescended testes and do not need to be operated on. In normal males, as the cremaster muscle relaxes or contracts, the testis moves lower or higher ("retracts") in the scrotum. This cremasteric reflex is much more active in infant boys than older men. A retractile testis high in

neg: Male reproductive system development of the gubernaculum, which subsequently pulls and translocates the testis down into the developing scrotum. Ultimately, the passageway closes behind the testis. A failure in this process can cause indirect inguinal hernia or an infantile hydrocoele.The testes descend into the scrotal sac between the sixth and 10th week. Dissent into this not occur until about the 28th week when compared and we know canals form and the abdominal wall to provide openings from the pelvic cavity to the scrotal sac. The process by which a testis to send is not well understood but it seems to be associated with

neg: Scrotal ultrasound or lateral to the testis [Fig. 27a]. Color flow and duplex Doppler US optimized for low-flow velocities help confirm the venous flow pattern, with phasic variation and retrograde filling during a Valsalva’s maneuver [Fig. 27b]. Intratesticular varicocele may appear as a vague hypoechoic area in the testis or mimics tubular ectasia. With color Doppler, this intratesticular hypoechoic area also showed reflux of vascular flow during Valsalva’s maneuver [Fig. 28]. Normally the testes begin its descent through the inguinal canal to the scrotum at 36 weeks’ of gestation and completed at birth. Failure in the course of testes descent will result

neg: Cryptorchidism the genitofemoral nerve to release calcitonin gene-related peptide, which produces rhythmic contractions of the gubernaculum, a ligament which connects the testis to the scrotum, but a similar mechanism has not been demonstrated in humans. Maldevelopment of the gubernaculum, or deficiency or insensitivity to either AMH or androgen can, therefore, prevent the testes from descending into the scrotum. Some evidence suggests an additional paracrine hormone, referred to as descendin, may be secreted by the testes. In many infants with inguinal testes, further descent of the testes into the scrotum occurs in the first 6 months of life. This is attributed to

neg: Gubernaculum Gubernaculum The paired gubernacula (from Ancient Greek κυβερνάω = pilot, steer, also called the caudal genital ligament) are embryonic structures which begin as undifferentiated mesenchyme attaching to the caudal end of the gonads (testes in males and ovaries in females). As the scrotum and labia majora form in males and females respectively, the gubernaculum aids in the descent of the gonads (both testes and ovaries). The testes descend to a greater degree than the ovaries and ultimately pass through the inguinal canal. The gubernaculum is present only during the development of the urinary and reproductive organs, being replaced by distinct

neg: Gubernaculum vestiges in males and females. In "males": In "females": Gubernaculum The paired gubernacula (from Ancient Greek κυβερνάω = pilot, steer, also called the caudal genital ligament) are embryonic structures which begin as undifferentiated mesenchyme attaching to the caudal end of the gonads (testes in males and ovaries in females). As the scrotum and labia majora form in males and females respectively, the gubernaculum aids in the descent of the gonads (both testes and ovaries). The testes descend to a greater degree than the ovaries and ultimately pass through the inguinal canal. The gubernaculum is present only during the development of

neg: Congenital adrenal hyperplasia due to 3β-hydroxysteroid dehydrogenase deficiency an undervirilized male with normal sensitivity to testosterone. If the infant boy is only mildly undervirilized, the hypospadias can be surgically repaired, testes brought into the scrotum, and testosterone supplied at puberty. Management decisions are more difficult for a moderately or severely undervirilized genetic male whose testes are in the abdomen and whose genitalia look at least as much female as male. Male sex can assigned and major reconstructive surgery done to close the midline of the perineum and move the testes into a constructed scrotum. Female sex can be assigned and the testes removed and vagina enlarged surgically. A

neg: Eastern mole openings in the groin area: the female has three – the forward one is the urinary opening (in the urinary papilla or projection), the second is the vagina, and the third is the anus at the tail. The male has two openings – the combined urinary/reproductive opening in the penis, and the anus. The testes never descend into a scrotum but remain within the body cavity. There are six teats on the belly – a pair at the chest, a pair at the groin, and a pair between the two. A rank, musky odor is emitted from a scent gland

neg: Vaginal process cause of testicular torsion, since lack of attachment to the inner lining of the scrotum leaves the testicles free to twist. Vaginal process 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.

neg: Scrotum upon the ambient temperature. This is accomplished by the cremaster muscle in the abdomen and the dartos fascia (muscular tissue under the skin). Having the scrotum and testicles situated outside the abdominal cavity may provide additional advantages. The external scrotum is not affected by abdominal pressure. This may prevent the emptying of the testes before the sperm were matured sufficiently for fertilization. Another advantage is it protects the testes from jolts and compressions associated with an active lifestyle. Animals that move at a steady pace – such as elephants, whales, and marsupial moles – have internal testes and no scrotum.

neg: Dasypus usually avoid chewing altogether. Armadillos of the genus "Dasypus" often pair during the breeding season, whereas they are usually solitary animals. While pairing, the male and female intermittently interact while foraging. These interactions include tail wagging, dorsal touching, sniffing, and tail lifting of the female. Females have an external clitoris and a urogenital sinus, which acts as both a urethra and vagina. Males are slightly larger than females in size and have testes that descend into the pelvis and a prominent penis. They lack a scrotum. In order to copulate, the female has to lie on her back due to

neg: Scrotum groove closes by week 12. Though the testes and scrotum form early in embryonic life, sexual maturation begins upon entering puberty. The increased secretion of testosterone causes the darkening of the skin and development of pubic hair on the scrotum. The scrotum regulates the temperature of the testes and maintains it at 35 degrees Celsius (95 degrees Fahrenheit), i.e. two degrees below the body temperature of 37 degrees Celsius (98.6 degrees Fahrenheit). Higher temperatures affect spermatogenesis Temperature control is accomplished by the smooth muscles of the scrotum moving the testicles either closer to or further away from the abdomen dependent

neg: Cryptorchidism develop, and differentiate. The testes remain high in the abdomen until the seventh month of gestation, when they move from the abdomen through the inguinal canals into the two sides of the scrotum. Movement has been proposed to occur in two phases, under the control of somewhat different factors. The first phase, movement across the abdomen to the entrance of the inguinal canal, appears controlled (or at least greatly influenced) by anti-Müllerian hormone (AMH). The second phase, in which the testes move through the inguinal canal into the scrotum, is dependent on androgens (most importantly testosterone). In rodents, androgens induce

neg: Mammal when not erect, and some placentals also have a penis bone ([[baculum]]). Marsupials typically have forked penises while the monotreme penis generally has four heads with only two functioning. The [[testes]] of most mammals descend into the [[scrotum]] which is typically posterior to the penis but is often anterior in marsupials. Female mammals generally have a [[clitoris]], [[labia majora]] and [[labia minora]] on the outside, while the internal system contains paired [[oviduct]]s, 1-2 [[uteri]], 1-2 [[Cervix|cervice]]s and a [[vagina]]. Marsupials have two lateral vaginas and a medial vagina. The "vagina" of monotremes is better understood as a "urogenital sinus". The

neg: Cryptorchidism and 4 years after birth. Some evidence indicates early orchiopexy reduces this degeneration. At least one contributing mechanism for reduced spermatogenesis in cryptorchid testes is temperature. The temperature of testes in the scrotum is at least a few degrees cooler than in the abdomen. Animal experiments in the middle of the 20th century suggested that raising the temperature could damage fertility. Some circumstantial evidence suggests tight underwear and other practices that raise the testicular temperature for prolonged periods can be associated with lower sperm counts. Nevertheless, research in recent decades suggests that the issue of fertility is more complex than

neg: Orchiopexy opening(s) performs the procedure. The higher the testicle, the less successful the procedure. However, the procedure has a high success rate overall. RETRACTILE TESTES This is a kind in which testes are neither fully descended nor purely undescended but testicles are somewhat movable. Means sometimes testes is visible in scrotum and sometimes retract upwards. However this condition is not so dangerous as compared to testes in abdominal cavity but needs surgery/ orchiopexy if testes remain maximum time in abdomen and less in scrotum. Orchiopexy can also be performed to resolve a testicular torsion. If caught early enough and the blood

neg: Tunica vaginalis Tunica vaginalis The tunica vaginalis is the pouch of serous membrane that covers the testes. It is derived from the vaginal process of the peritoneum, which in the fetus precedes the descent of the testes from the abdomen into the scrotum. After its descent, that portion of the pouch which extends from the abdominal inguinal ring to near the upper part of the gland becomes obliterated; the lower portion remains as a shut sac, which invests the surface of each testis, and is reflected on to the internal surface of the scrotum; hence it may be described as consisting of

neg: Development of the gonads (pre-granulosa cells). In this way, the rudiments of the ovarian follicles are formed. In the testis, a network of tubules fuse to create the seminiferous tubules. Via the rete testis, the seminiferous tubules become connected with outgrowths from the mesonephros, which form the efferent ducts of the testis. The descent of the testes consists of the opening of a connection from the testis to its final location at the anterior abdominal wall, followed by the development of the gubernaculum, which subsequently pulls and translocates the testis down into the developing scrotum. Ultimately, the passageway closes behind the testis. A failure

neg: Development of the reproductive system develops the seminiferous tubules. Via the rete testis, the seminiferous tubules become connected with outgrowths from the mesonephros, which form the efferent ducts of the testis. In short, the descent of the testes consists of the opening of a connection from the testis to its final location at the anterior abdominal wall, followed by the development of the gubernaculum, which subsequently pulls and translocates the testis down into the developing scrotum. Ultimately, the passageway closes behind the testis. A failure in this process can cause indirect inguinal hernia or an infantile hydrocoele. After the separation of the rectum from the

neg: Fox pouncing technique where they crouch down to camouflage themselves in the terrain, then using their hind legs, leap up with great force to land on top of their targeted prey. Using their pronounced canine teeth, foxes grip on to their prey's neck and either shake until the prey is dead, or until the animal can be disemboweled. The gray fox is one of only two canine species known to regularly climb trees; the other is the raccoon dog. The male fox's scrotum is held up close to the body with the testes inside even after they descend. Like other canines,

neg: Kallmann syndrome history of un-descended testes. Affected individuals with KS and other forms of HH are almost invariably born with normal sexual differentiation; i.e., they are physically male or female. This is due to the human chorionic gonadotrophin (hCG) produced by placenta at approximately 12 to 20 weeks gestation (pregnancy) which is normally unaffected by having KS or CHH. People with KS/HH lack the surge of GnRH, LH, and FSH that normally occurs between birth and six months of age. This surge is particularly important in infant boys as it helps with testicular descent into the scrotum. The surge of GnRH/LH/FSH in

neg: Hippopotamus They are incapable of jumping but do climb up steep banks. Despite being semiaquatic and having webbed feet, an adult hippo is not a particularly good swimmer nor can it float. It is rarely found in deep water; when it is, the animal moves by porpoise-like leaps from the bottom. The eyes, ears, and nostrils of hippos are placed high on the roof of their skulls. This allows these organs to remain above the surface while the rest of the body submerges. The testes of the males descend only partially and a scrotum is not present. In addition, the penis

neg: Male reproductive system penis, and a midline closure of the labioscrotal folds. This closure forms the wall of the scrotum the external genitalia. The external genitalia are completely formed by the end of the 12th week. At birth, the development of the prepubertal male reproductive system is completed. During the second trimester of pregnancy, testosterone secretion in the male declines so that at birth the testes are inactive. Gonadotropin secretion is low until the beginning of puberty. The genetic sex is determined by whether a Y bearing or next bearing sperm fertilizes the open; the presence or absence of a Y chromosome in

neg: Spermatogenesis system. The initial stages occur within the testes and progress to the epididymis where the developing gametes mature and are stored until ejaculation. The seminiferous tubules of the testes are the starting point for the process, where spermatogonial stem cells adjacent to the inner tubule wall divide in a centripetal direction—beginning at the walls and proceeding into the innermost part, or "lumen"—to produce immature sperm. Maturation occurs in the epididymis. The location [Testes/Scrotum] is specifically important as the process of spermatogenesis requires a lower temperature to produce viable sperm, specifically 1°-8 °C lower than normal body temperature of 37 °C

neg: Testicle that cool the arterial blood going to the testes by placing the arteries near veins bringing cooled venous blood from the skin. Boreoeutherian land mammals, the large group of mammals that includes humans, have externalized testes. Their testes function best at temperatures lower than their core body temperature. Their testes are located outside of the body, suspended by the spermatic cord within the scrotum. There are several hypotheses why most boreotherian mammals have external testes which operate best at a temperature that is slightly less than the core body temperature, e.g. that it is stuck with enzymes evolved in a

neg: Sexual differentiation in humans development can only occur when the fetal testis secretes key hormones at a critical period in early gestation. The testes begin to secrete three hormones that influence the male internal and external genitalia: they secrete anti-müllerian hormone (AMH), testosterone, and dihydrotestosterone (DHT). Anti-müllerian hormone causes the paramesonephric ducts to regress. Testosterone converts the mesonephric ducts into male accessory structures, including the epididymis, vas deferens, and seminal vesicle. Testosterone will also control the descending of the testes from the abdomen into the scrotum. Many other genes found on other autosomes, including"WT-1", "SOX9", "SF-1" also play a role in gonadal development. Females:

neg: Gelding butorphanol, and often physically restrained. Local anaesthetic is injected into the parenchyma of both testes. An incision is made through the scrotum and the testes are removed, then the spermatic cord is crushed, most commonly with either ligatures or emasculators, or both. The emasculators are applied for two to three minutes, then removed, and a careful check is made for signs of haemorrhage. Assuming that bleeding is at a minimum, the other side is castrated in the same manner. Most veterinarians remove the testis held most "tightly" (or close to the body) by the cremaster muscle first, so as to

neg: Scrotum Scrotum The scrotum is an anatomical male reproductive structure that consists of a suspended dual-chambered sack of skin and smooth muscle that is present in most terrestrial male mammals and located under the penis. One testis is typically lower than the other to avoid compression in the event of impact. The perineal raphe is a small, vertical, slightly raised ridge of scrotal skin under which is found the scrotal septum. It appears as a thin longitudinal line that runs front to back over the entire scrotum. The scrotum contains the external spermatic fascia, testes, epididymis and ductus deferens. It is

neg: Testicular torsion is termed an extravaginal testicular torsion. This type occurs exclusively in newborns, however, newborns can be affected by other testicular torsion variants as well. Neonates experiencing such a torsion typically present with painless scrotal swelling, discoloration, and a firm, painless mass in the scrotum. Such testes are usually necrotic from birth and must be removed surgically. The exact cause of or specific risk factors for extravaginal torsion in this population remain unclear. The testicular appendix is located in the upper pole of the testicle. It is an embryonic remnant that has no known function, but is at risk for torsion

neg: Tunica vaginalis tunica albuginea sends prolongations inwards, dividing the testicle into lobules. Each lobule contains the seminiferous tubules, extending from the base where they end blindly, towards the apex. Tunica vaginalis The tunica vaginalis is the pouch of serous membrane that covers the testes. It is derived from the vaginal process of the peritoneum, which in the fetus precedes the descent of the testes from the abdomen into the scrotum. After its descent, that portion of the pouch which extends from the abdominal inguinal ring to near the upper part of the gland becomes obliterated; the lower portion remains as a shut

neg: Testicle spermatogenesis is less efficient at lower and higher temperatures than 33 °C. Because the testes are located outside the body, the smooth tissue of the scrotum can move them closer or further away from the body. The temperature of the testes is maintained at 35 degrees Celsius (95 degrees Fahrenheit), i.e. two degrees below the body temperature of 37 degrees Celsius (98.6 degrees Fahrenheit). Higher temperatures affect spermatogenesis. There are a number of mechanisms to maintain the testes at the optimum temperature. The cremasteric muscle is part of the spermatic cord. When this muscle contracts, the cord is shortened and

neg: Vaginal process Vaginal process 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. If it does not close in females, it forms the canal of Nuck. Failure of closure of the vaginal process leads

neg: Testicle Testicle The testicle or testis is the male reproductive gland in all animals, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testosterone. Testosterone release is controlled by the anterior pituitary luteinizing hormone; whereas sperm production is controlled both by the anterior pituitary follicle-stimulating hormone and gonadal testosterone. Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry is not unusual: one testicle extends further down into the scrotum than the other due to differences in

neg: Testicular trauma Testicular trauma Testicular trauma is an injury to one or both testicles. Types of injuries include blunt, penetrating and degloving. Because the testes are located within the scrotum, which hangs outside of the body, they do not have the protection of muscles and bones. This makes it easier for the testes to be struck, hit, kicked or crushed, which occurs most often during contact sports. Testicles can be protected by wearing athletic cups during sports. Trauma to the testes can cause severe pain, bruising, swelling, and/or in severe cases even infertility. In most cases, the testes—which are made of a

neg: Scrotum the right. An alternative view is that testis descent asymmetry evolved to enable more effective cooling of the testicles. Additional tissues and organs reside inside the scrotum and are described in more detail in the following articles: Male sex hormones are secreted by the testes later in embryonic life to cause the development of secondary sex organs. The scrotum is developmentally homologous to the labia minora and labia majora. The raphe does not exist in females. Reproductive organs and tissues develop in females and males begin during the fifth week after fertilization. The gonadal ridge grows behind the peritoneal membrane.

neg: Cryptorchidism the scrotum can be difficult to distinguish from a position in the lower inguinal canal. Though various maneuvers are used to do so, such as using a cross-legged position, soaping the examiner's fingers, or examining in a warm bath, the benefit of surgery in these cases can be a matter of clinical judgment. In the minority of cases with bilaterally nonpalpable testes, further testing to locate the testes, assess their function, and exclude additional problems is often useful. Scrotal ultrasound or magnetic resonance imaging performed and interpreted by a radiologist can often locate the testes while confirming absence of a

neg: Androgen which prevents the embryonic Müllerian ducts from developing into fallopian tubes and other female reproductive tract tissues in male embryos. MIH and androgens cooperate to allow for movement of testes into the scrotum. Before the production of the pituitary hormone luteinizing hormone (LH) by the embryo starting at about weeks 11–12, human chorionic gonadotrophin (hCG) promotes the differentiation of Leydig cells and their production of androgens at week 8. Androgen action in target tissues often involves conversion of testosterone to 5α-dihydrotestosterone (DHT). At the time of puberty, androgen levels increase dramatically in males, and androgens mediate the development of masculine

neg: Labia Sexual differentiation starts on the internal sex organs at about 5 weeks of gestation, resulting in the formation of either testes in males, or ovaries in females. If testes are formed, they begin to secrete androgens that affect the external genital development at about week 8 or 9 of gestation. The urogenital folds form the labia minora in females, or penile shaft in males. The labioscrotal swellings become the labia majora in females, or they fuse to become the scrotum in males. Because the male and female parts develop from the same tissues, this makes them homologous (different versions of

neg: Spermatogenesis is sensitive to elevated temperature in humans and some other species, and will be adversely affected by temperatures as high as normal body temperature. Consequently, the testes are located outside the body in a sack of skin called the scrotum. The optimal temperature is maintained at 2 °C (man)–8 °C (mouse) below body temperature. This is achieved by regulation of blood flow and positioning towards and away from the heat of the body by the cremasteric muscle and the dartos smooth muscle in the scrotum. Dietary deficiencies (such as vitamins B, E and A), anabolic steroids, metals (cadmium and lead),

neg: Georges Burou was extended along the raphe of the scrotum to the root of the penis. The surgical field was widened by retracting the scrotal skin on both sides and widely exposing the corpus spongiosum, both corpora cavernosa, and the two testes. Once the testes and their pedicles had been dissected, the spermatic cord was cut and ligated. Then, both corpora cavernosa were ligated and cut at a level just distally to their attachment to the inferior ramus of the pubic bone. The level of transection of the spongious bulb and urethra had to correspond with the length of the future urethra.

neg: Testicle have seasonal breeding cycles keep their testes internal until the breeding season at which point their testes descend and increase in size and become external. 2) "Irreversible adaptation to sperm competition". It has been suggested that the ancestor of the boreoeutherian mammals was a small mammal that required very large testes (perhaps rather like those of a hamster) for sperm competition and thus had to place its testes outside the body. This led to enzymes involved in spermatogenesis, spermatogenic DNA polymerase beta and recombinase activities evolving a unique temperature optimum, slightly less than core body temperature. When the boreoeutherian mammals

neg: Rhode Island School of Design logo consists of two balls next to one another in an irregularly shaped net. Lest the sexual message of these teams and logos be lost, the 2001 creation of the school mascot, Scrotie, ended any ambiguity. Despite the name, Scrotie is not merely a representation of a scrotum, but is a 7-foot tall penis, with scrotum and testes at the bottom. RISD has stated that Scrotie is only an "unofficial" mascot, yet Scrotie is featured prominently on the school's official website. In 2016, the school reported that the 2009 incarnation of the mascot had been deemed not appropriate for younger

neg: Inguinal canal define the boundaries, these canals are often further approximated as boxes with six sides. Not including the two rings, the remaining four sides are usually called the "anterior wall", "inferior wall ("floor")", "superior wall ("roof")", and "posterior wall". These consist of the following: During development each gonad (ovary or testicle) descend from their starting point on the posterior abdominal wall (para-aortically) from the labioscrotal swellings near the kidneys, down the abdomen, and through the inguinal canals to reach the scrotum. Each testicle then descends through the abdominal wall into the scrotum, behind the processus vaginalis (which later obliterates). Thus lymphatic

neg: Mantled howler at which point maternal care ends. Adult females typically give birth every 19 to 23 months, assuming the prior infant survived to weaning. The mantled howler differs from other howler monkey species in that the males' testes do not descend until they reach sexual maturity. Upon reaching sexual maturity, the young monkeys are usually evicted from their natal group, although the offspring of a high-ranking female may get to stay in its natal group. However, many infants do not reach sexual maturity; high-ranking adults sometimes harass or kill the offspring of lower-ranking monkeys to eliminate competition to their own offspring

neg: Development of the gonads the testis to its final location at the anterior abdominal wall, followed by the development of the gubernaculum, which subsequently pulls and translocates the testis down into the developing scrotum. Ultimately, the passageway closes behind the testis. At an early period of fetal life the testes are placed at the back part of abdominal cavity, behind the peritoneum, and each is attached by a peritoneal fold, the mesorchium, to the mesonephros. From the front of the mesonephros a fold of peritoneum termed the inguinal fold grows forward to meet and fuse with a peritoneal fold, the inguinal crest, which grows

neg: Testicular torsion vomiting. The testicle may lie higher in the scrotum due to twisting and subsequent shortening of the spermatic cord or may be positioned in a horizontal orientation. Mild warmth and redness of the overlying area may be present. Elevation of the testicle may worsen the pain. The cremasteric reflex, which normally causes elevation of the testicle by stroking the inner thigh, may be absent, especially in children. Urinary symptoms, such as pain or increased frequency of urination are also typically absent. Symptom onset often follows physical activity or trauma to the testes or scrotum. Children with testicular torsion may awaken

neg: Scrotifera Scrotifera Scrotifera is a clade of placental mammals that comprises the following orders and their common ancestors: Chiroptera, Carnivora, Pholidota, Perissodactyla and Cetartiodactyla, with the latter including the traditional orders Artiodactyla and Cetacea. Scrotifera is the sister group to the Eulipotyphla and together they make up the Laurasiatheria. Peter Waddell, then of the Institute of Statistical Mathematics, explains the etymology of the clade's name as follows: The name comes from the word scrotum, a pouch in which the testes permanently reside in the adult male. All members of the group have a postpenile scrotum, often prominently displayed, except for some

neg: Development of the gonads into the scrotum. It seems certain also that the gubernacular cord becomes shortened as development proceeds, and this assists in causing the testis to reach the bottom of the scrotum. By the end of the eighth month the testis has reached the scrotum, preceded by the saccus vaginalis, which communicates by its upper extremity with the peritoneal cavity. Just before birth the upper part of the saccus vaginalis, at the internal inguinal ring, usually becomes closed, and this obliteration extends gradually downward to within a short distance of the testis. The process of peritoneum surrounding the testis is now entirely

neg: Fetal pig behind the hind legs of the fetal pig is the scrotum. The male's internal reproductive system has two scrotal sacs, which depending on the age of the fetal pig may or may not have developed testes. The epididymis coil on the testes connects to the vas deferens. The vas deferens crosses over the ureter and enters the urethra, which then connects to the penis located just posterior to the skin. Similar to the female system, it may be difficult to identify all parts. Fetal pig Fetal pigs are unborn pigs used in elementary as well as advanced biology classes as

neg: Sex organ the middle, and the urethra behind the protuberance. If the fetus has testes, and if the testes produce testosterone, and if the cells of the genitals respond to the testosterone, the outer urogenital folds swell and fuse in the midline to produce the scrotum; the protuberance grows larger and straighter to form the penis; the inner urogenital swellings grow, wrap around the penis, and fuse in the midline to form the penile urethra. Each sex organ in one sex has a homologous counterpart in the other one. See a list of homologues of the human reproductive system. In a larger

neg: Transillumination other wavelengths of light. Organs analysed include the sinuses, the breasts and the testes. It is widely used by pediatricians to shine light in bodies of infants and observe the amount of scattered light. Since their skeleton is not fully calcified, light can easily penetrate tissues. Common examples of diagnostic applications are: Failed obliteration of the processus vaginalis allows serous fluid to collect around the testes via a communicating connection between the tunica vaginalis and the peritoneum. The resulting hydrocele presents as a painless enlargement of the scrotum, similar to what may be encountered with testicular neoplasms. A convenient method

neg: Testicle with a layer of cells (germ cells) that develop from puberty through old age into sperm cells (also known as spermatozoa or male gametes). The developing sperm travel through the seminiferous tubules to the rete testis located in the mediastinum testis, to the efferent ducts, and then to the epididymis where newly created sperm cells mature (see spermatogenesis). The sperm move into the vas deferens, and are eventually expelled through the urethra and out of the urethral orifice through muscular contractions. Blood supply and lymphatic drainage of the testes and scrotum are distinct: Many anatomical features of the adult testis

neg: Scrotal ultrasound be performed. A high resolution, near-focused, linear array transducer with a frequency of 7.5 MHz or greater is often used because it provides increased resolutions of the scrotal contents. Images of both scrotum and bilateral inguinal regions are obtained in both transverse and longitudinal planes. Color Doppler and pulsed Doppler examination is subsequently performed, optimized to display low-flow velocities, to demonstrate blood flow in the testes and surrounding scrotal structures. In evaluation of acute scrotum, the asymptomatic side should be scanned first to ensure that the flow parameters are set appropriately. A transverse image including all or a portion of

neg: American shrew mole sex chromosomes are XX in females and XY in males. The Y chromosome in males is very small and appears to be similar in all species. It can have several litters annually, except in December through January because no litter have been noted during these months. Females have litters with one to four young. Newborns are about 30 millimeters long and weigh less than 1 gram. In females, the vagina remains sealed until follicles appear in the ovaries. In males, they lack a scrotum, but the testes and glands that associate with the testes become enlarges, which increases their weight.

neg: Cryptorchidism worth the trouble, since the surgery itself is usually simple and uncomplicated. In cases where the testes are identified preoperatively in the inguinal canal, orchiopexy is often performed as an outpatient and has a very low complication rate. An incision is made over the inguinal canal. The testis with accompanying cord structure and blood supply is exposed, partially separated from the surrounding tissues ("mobilized"), and brought into the scrotum. It is sutured to the scrotal tissue or enclosed in a "subdartos pouch". The associated passage back into the inguinal canal, an inguinal hernia, is closed to prevent reascent. In patients

neg: Semen quality with an elevation in temperature of 0.8-1° caused by wearing constrictive underwear, no changes in sperm parameters, no decrease in spermatogenesis, and no changes in sperm function are observed A blow from outside does not affect the sperm quality of already produced sperm cells. Furthermore, the testes are well protected in the scrotum, for example by the tunica vaginalis, making the testes slide away from external pressure rather than being malformed from it; however, a hard enough hit can close or crush the capillaries that supply the sperm producing tissue, resulting in permanent or temporary and partial or total inability

neg: Isolated 17,20-lyase deficiency of sex hormones). Males and females may be treated with hormone replacement therapy (i.e., with androgens and estrogens, respectively), which will result in normal sexual development and resolve most symptoms. In the case of 46,XY (genetically male) individuals who are phenotypically female and/or identify as the female gender, they should be treated with estrogens instead. Removal of the undescended testes should be performed in 46,XY females to prevent their malignant degeneration, whereas in 46,XY males surgical correction of the genitals is generally required, and, if necessary, an orchidopexy (relocation of the undescended testes to the scrotum) may be performed as

neg: Androgen insensitivity syndrome this anti-Müllerian hormone, the Müllerian ducts develop into the female internal genitalia (uterus, cervix, fallopian tubes, and upper vaginal barrel). Unlike the Müllerian ducts, the Wolffian ducts will not continue to develop by default. In the presence of testosterone and functional androgen receptors, the Wolffian ducts develop into the epididymides, vasa deferentia, and seminal vesicles. If the testes fail to secrete testosterone, or the androgen receptors do not function properly, the Wolffian ducts degenerate. Masculinization of the male external genitalia (the penis, penile urethra, and scrotum), as well as the prostate, are dependent on the androgen dihydrotestosterone. Testosterone is converted

neg: Inguinal hernia pinched within the hernia, causing an intestinal obstruction. If the blood supply of the portion of the intestine caught in the hernia is compromised, the hernia is deemed "strangulated" and gut ischemia and gangrene can result, with potentially fatal consequences. The timing of complications is not predictable. In men, indirect hernias follow the same route as the descending testes, which migrate from the abdomen into the scrotum during the development of the urinary and reproductive organs. The larger size of their inguinal canal, which transmitted the testicle and accommodates the structures of the spermatic cord, might be one reason why

neg: Mountain beaver animals. The skull is protrogomorphous; it has no specialized attachments for the masseter muscles as seen in other rodents. It is flattened and lacks a postorbital process. The baculum is thin and distinctly forked. The penis is about in length. The male does not have a true scrotum, but the testes move into a position called semiscrotal during the breeding season. Mountain beavers have an unusual projection on each molar and premolar tooth, which is unique among mammals and allows for easy identification of teeth. This projection points toward the cheek on the upper tooth row, but points toward the

neg: Persistent Müllerian duct syndrome differentiate into epididymides, vasa deferentia and seminal vesicles under the influence of testosterone, produced by the fetal Leydig cells The main form of treatment is laparotomy, a modern and minimally invasive type of surgery. Laparotomy properly positions the testes within the scrotum (orchidopexy) and remove Mullerian structures being the uterus and fallopian tubes. Occasionally they are unsalvageable if located high in the retroperitoneum. During this surgery, the uterus is usually removed and attempts made to dissect away Müllerian tissue from the vas deferens and epididymis to improve the chance of fertility. If the person has male gender identity himself and

neg: No scalpel vasectomy purposes irreversible. Thus, it is recommended that the man have a living child before proceeding with the surgery. The Government of India stipulates more stringent criteria: No scalpel vasectomy is performed under local anaesthesia. Usually lidocaine 2 percent is infiltrated into the vas deferens and the puncture site on the scrotum. This makes the procedure pain free. Some patients may prefer to receive regional anaesthesia. The vas deferens is isolated by three-finger technique on both sides. The ideal entry point for the needle is midway between the top of the testes and the base of the penis. Usually, 100 mg

neg: Even-toed ungulate this curvature to extend, which leads to an extension, but not a thickening, of the penis. Cetaceans have similar penises. In some even-toed ungulates, the penis contains a structure called the "urethral process." The testicles are located in the scrotum and thus outside the abdominal cavity. The ovaries of many females descend – as testicles descend of many male mammals – and are close to the pelvic inlet at the level of the fourth lumbar vertebra. The uterus has two horns (uterus bicornis). <section end=genitourinary_system /> The number of mammary glands is variable and correlates, as in all mammals, with

neg: Development of the endocrine system to 35 weeks of gestation), the testicles descend into the scrotum. This stage is regulated by androgens, the genitofemoral nerve, and calcitonin gene-related peptide. During the second and third trimester, testicular development concludes with the diminution of the fetal Leydig cells and the lengthening and coiling of the seminiferous cords. For females, the ovaries become morphologically visible by the 8th week of gestation. The absence of testosterone results in the diminution of the Wolffian structures. The Müllerian structures remain and develop into the fallopian tubes, uterus, and the upper region of the vagina. The urogenital sinus develops into the urethra

neg: Elastration are castrated within the first one or two days the testes may sometimes be small and soft enough to be drawn up through the ring, and they continue to develop above the scrotum – surgical castration then becomes necessary. Improper use of banding on cats can result in death and charges of cruelty. The same tool and rings are also used to dock the tails of many breeds of sheep, to prevent dung building up on the tails (which can lead to fly strike). This is usually done at the same time as castration of the ram lambs. It is

neg: Congenital adrenal hyperplasia due to 21-hydroxylase deficiency testosterone in the blood can enlarge the phallus, partially or completely close the vaginal opening, enclose the urethral groove so that it opens at the base of the phallus, on the shaft or even at the tip like a boy. Testosterone can cause the labial skin to become as thin and rugated as a scrotum, but cannot produce palpable gonads (i.e., testes) in the folds. Thus, depending on the severity of hyperandrogenism, a female infant can be mildly affected, obviously ambiguous, or so severely virilized as to appear to be a male. Andrea Prader devised the following Prader scale as

neg: Penis the prepuce (foreskin, or sheath). Tapirs have exceptionally long penises relative to their body size. The glans of the Malayan tapir resembles a mushroom, and is similar to the glans of the horse. The penis of the Sumatran rhinoceros contains two lateral lobes and a structure called the "processus glandis". All members of Carnivora (except hyenas) have a baculum.Canine penises have a structure at the base called the bulbus glandis. During copulation, the spotted hyena inserts his penis through the female's pseudo-penis instead of directly through the vagina, which is blocked by the false scrotum and testes. Once the female

neg: Heat-based contraception Heat-based contraception An experimental male contraceptive method involves heating the testicles so that they cannot produce sperm. Sperm are best produced at a temperature slightly below body temperature. The muscles around a male's scrotum involuntarily tighten if the man's body temperature drops, and they loosen, allowing the testes to hang, if the body temperature rises. This is the body's way of keeping the sperm at an ideal temperature. Although research has not addressed methods of applying heat, sperm production can be disrupted with increased temperature. Some suggest exposure to high temperatures (116 °F equal to 47 °C) can affect infertility

neg: Thylacine film footage confirmed that the thylacine was male. When frame III is enlarged the scrotum can be seen, confirming the thylacine to be male. By enhancing the frame (increasing exposure to 20% and contrast to 45%), the outline of the individual testes is discernable. After the thylacine's death the zoo expected that it would soon find a replacement, and "Benjamin"'s death was not reported on in the media at the time. Although there had been a conservation movement pressing for the thylacine's protection since 1901, driven in part by the increasing difficulty in obtaining specimens for overseas collections, political difficulties

neg: Adolescence and may receive inadequate nutrition from diets that often lack important nutrients, such as iron. These environmental influences in turn affect female physical development. Primary sex characteristics are those directly related to the sex organs. In males, the first stages of puberty involve growth of the testes and scrotum, followed by growth of the penis. At the time that the penis develops, the seminal vesicles, the prostate, and the bulbourethral gland also enlarge and develop. The first ejaculation of seminal fluid generally occurs about one year after the beginning of accelerated penis growth, although this is often determined culturally rather

neg: Azoospermia gametogenesis. Polymorphisms in these genes were tested for associations with male infertility. Single nucleotide polymorphisms in two of these genes ("TEX11" and "MLH3") were found to be associated with male infertility involving azoospermy or oligospermia. Azoospermia is usually detected in the course of an infertility investigation. It is established on the basis of two semen analysis evaluations done at separate occasions (when the seminal specimen after centrifugation shows no sperm under the microscope) and requires a further work-up. The investigation includes a history, a physical examination including a thorough evaluation of the scrotum and testes, laboratory tests, and possibly imaging.

neg: Cock ring that latter offering more friction on the penis and are therefore less likely to slip. Many of the newer rings also have different accessories and projections. There are also vibrating cock rings available which can stimulate the testes at the same time. Today, cock rings can be bought with accessories that stimulate the clitoris or anal area during intercourse. Other cock rings go around the scrotum and can significantly enhance erection and intensity of orgasms. However, there is one negative: the more accessories that are added on, the greater the chance of developing discomfort or cold sensations from the device.

neg: Semelparity and iteroparity grow back, even if the male survives months after the first mating season. As the marsupial ages, its testicles grow until they reach a peak size and weight at the beginning of the mating season. After the individual mates, the weight and size of the testes and scrotum decrease. They remain small and do not produce spermatozoa later in life, if maintained in a laboratory. The 1966 Woolley study on "Antechinus spp." noticed that males were only able to be maintained past mating in the laboratory and no senile males were found in the wild, suggesting that all males die

neg: Complete androgen insensitivity syndrome Chromosome. The cells of unaffected genetic males then masculinize by, among other things, enlarging the genital tubercle into a penis but in females it becomes the clitoris, while what in females becomes the labia fuses to become the scrotum of males (where the testicles will later descend). Genetically male individuals affected by CAIS, however, will develop a normal external female habitus, despite the presence of a Y chromosome, but internally, they will lack a uterus, and the vaginal cavity will be shallow, while the gonads, having been turned into testicles rather than ovaries in the earlier separate process also triggered

neg: Intersex medical interventions that of a completely virilized XX child with congenital adrenal hyperplasia (Prader stage 5) being raised as a male; ovaries and uterus must be removed to prevent breast development and menstruation by early adolescence. Potential surgical problems: Risks are simply those of abdominal surgery. Testicular prostheses are saline-filled plastic ovoids implanted in the scrotum. They have no function except to provide the appearance and feel of testes. Several sizes are available, but most are implanted in adolescence to avoid repeated procedures to implant larger sizes at puberty. Prostheses made of silastic are no longer available due to safety and perception-of-safety

neg: Dihydrotestosterone the body. In the condition, circulating testosterone levels are within or slightly above the normal male range, but DHT levels are low (around 30% of normal), and the ratio of circulating testosterone to DHT is greatly elevated (at about 3.5 to 5 times higher than normal). Genetic males (46,XY) with 5α-reductase type II deficiency are born with undervirilization including pseudohermaphroditism (ambiguous genitalia), pseudovaginal perineoscrotal hypospadias, and usually undescended testes. Their external genitalia are female-like, with micropenis (a small, clitoris-like phallus), a partially unfused, labia-like scrotum, and a blind-ending, shallow vaginal pouch. Due to their lack of conspicuous male genitalia, genetic

neg: Ridgling susceptible. As a young male animal reaches puberty, the testicles, which originally were inside the abdominal cavity, move down the inguinal canal to the scrotum. In a ridgling, either the testicles fail to descend, or they are trapped behind the external inguinal ring and cannot emerge. Usually both testicles in a horse have descended by the age of 16 months, but as many as 15% of all two- and three-year-old male horses may have a retained testicle. In dogs, the testicles usually descend by the time a puppy is 40 days old. An example of a ridgeling that was gelded

neg: Robinow syndrome a deformed pinna. Patients suffer from dwarfism, short lower arms, small feet, and small hands. Fingers and toes may also be abnormally short and laterally or medially bent. The thumb may be displaced and some patients, notably in Turkey, experience ectrodactyly. All patients often suffer from vertebral segmentation abnormalities. Those with the dominant variant have, at most, a single butterfly vertebra. Those with the recessive form, however, may suffer from hemivertebrae, vertebral fusion, and rib anomalies. Some cases resemble Jarcho-Levin syndrome or spondylocostal dysostosis. Genital defects characteristically seen in males include a micropenis with a normally developed scrotum and testes.

neg: Post-vasectomy pain syndrome testicular side following its blockage by vasectomy. The efferent ducts and seminiferous tubules of the testes are also impacted by backpressure, leading to an increase in area and thickness. Backpressure from blockage of the vas deferens causes a rupture in the epididymis, called an "epididymal blowout", in 50% of vasectomy patients. Sperm sometimes leak from the vas deferens of vasectomized men, forming lesions in the scrotum known as sperm granulomas. Some sperm granulomas can be painful. The presence of a sperm granuloma at the vasectomy site prevents epididymal pressure build-up, perforation, and the formation of an epididymal sperm granuloma. It

neg: Human reproduction may result in a 2-fold reduction in the heat-induced contribution to the spontaneous mutation rate in male germinal tissues compared to tissues at 37 °C. If the testicles remain too close to the body, it is likely that the increase in temperature will harm the spermatozoa formation, making conception more difficult. This is why the testes are carried in an external pouch viz. scrotum rather than within the abdomen; they normally remain slightly cooler than body temperature, facilitating sperm production. The female reproductive system likewise contains two main divisions: the vagina and the Ovum. The ovum meets with sperm cell,

neg: Spotted hyena show a similar preference, with the addition of preferring males with whom they have had long and friendly prior relationships. Passive males tend to have greater success in courting females than aggressive ones. Copulation in spotted hyenas is a relatively short affair, lasting 4–12 minutes, and typically only occurs at night with no other hyenas present. The mating process is complicated, as the male's penis enters and exits the female's reproductive tract through her pseudo-penis rather than directly through the vagina, which is blocked by the false scrotum and testes. These unusual traits make mating more laborious for the male

neg: Accessory spleen 1 centimeter, but sizes ranging from a few millimeters up to 2–3 centimeters are not uncommon. Splenogonadal fusion can result in one or more accessory spleens along a path from the abdomen into the pelvis or scrotum. The developing spleen forms near the urogenital ridge from which the gonads develop. The gonads may pick up some tissue from the spleen, and as they descend through the abdomen during development, they can produce either a continuous or a broken line of deposited splenic tissue. Splenosis is a condition where foci of splenic tissue undergo autotransplantation, most often following physical trauma or

neg: Inguinal canal it) Note that the ilioinguinal nerve passes through the superficial ring to descend into the scrotum, but does not formally run through the canal. Abdominal contents (potentially including intestine) can be abnormally displaced from the abdominal cavity. Where these contents exit through the inguinal canal, having passed through the deep inguinal ring, the condition is known as an indirect or oblique inguinal hernia. This can also cause infertility. This condition is far more common in males than in females, owing to the inguinal canal's small size in females. A hernia that exits the abdominal cavity directly through the deep layers

neg: Cryptorchidism the postnatal surge of gonadotropins and testosterone that normally occurs between the first and fourth months of life. Spermatogenesis continues after birth. In the third to fifth months of life, some of the fetal spermatogonia residing along the basement membrane become type A spermatogonia. More gradually, other fetal spermatogonia become type B spermatogonia and primary spermatocytes by the fifth year after birth. Spermatogenesis arrests at this stage until puberty. Most normal-appearing undescended testes are also normal by microscopic examination, but reduced spermatogonia can be found. The tissue in undescended testes becomes more markedly abnormal ("degenerates") in microscopic appearance between 2