Neurovascular anatomy of the developing human fetal penis and clitoris.

The human penile and clitoral development begins from a morphologically indifferent genital tubercle. Under the influence of androgen, the genital tubercle forms the penis by forming a tubular urethra within the penile shaft. Without the effect of the androgen, the genital tubercle differentiates into the clitoris, and a lack of formation of the urethra within the clitoris is observed. Even though there are similarities during the development of the glans penis and glans clitoris, the complex canalization occurring along the penile shaft eventually leads to a morphological difference between the penis and clitoris. Based on the morphological differences, the main goal of this study was to define the vascular and neuronal anatomy of the developing penis and clitoris between 8 and 12 weeks of gestation using laser scanning confocal microscopy. Our results demonstrated there is a co-expression of CD31, which is an endothelial cell marker, and PGP9.5, which is a neuronal marker in the penis where the fusion is actively occurring at the ventral shaft. We also identified a unique anatomical structure for the first time, the clitoral ridge, which is a fetal structure running along the clitoral shaft in the vestibular groove. Contrary to previous anatomical findings which indicate that the neurovascular distribution in the developing penis and clitoris is similar, in this study, laser scanning confocal microscopy enabled us to demonstrate finer differences in the neurovascular anatomy between the penis and clitoris.

Beyond the tip of the iceberg: A meta-analysis of the anatomy of the clitoris.

An understanding of ranges in clitoral anatomy is important for clinicians caring for patients including those who have had female genital mutilation, women seeking genital cosmetic surgery, or trans women seeking reconstructive surgery. The aim of this meta-analysis is to investigate the ranges in clitoral measurements within the literature. A meta-analysis was performed on Ovid Medline and Embase databases following the PRISMA protocol. Measurements of clitoral structures from magnetic imaging resonance, ultrasound, cadaveric, and living women were extracted and analyzed. Twenty-one studies met the inclusion criteria. The range in addition to the average length and width of the glans (6.40 mm; 5.14 mm), body (25.46 mm; 9.00 mm), crura (52.41 mm; 8.71 mm), bulb (52.00 mm; 10.33 mm), and prepuce (23.19 mm) was calculated. Furthermore, the range and average distance from the clitoris to the external urethral meatus (22.27 mm), vagina (43.14 mm), and anus (76.30 mm) was documented. All erectile and non-erectile structures of the clitoris present with substantial range. It is imperative to expand the literature on clitoral measurements and disseminate the new results to healthcare professionals and the public to reduce the sense of inadequacy and the chances of iatrogenic damage during surgery.

How well do we truly understand clitoral anatomy? An Irish maternity hospital's perspective.

BACKGROUND: The clitoris has long been ignored in medical literature and teaching, with the first paper describing its anatomy only published in 1993. It is essential that those working in women's health understand the anatomy of this important female sexual organ. AIMS: The aim of this study was to assess the level of knowledge of the anatomy of the clitoris across five cohorts in a busy teaching maternity hospital in Ireland. MATERIALS AND METHODS: A questionnaire was devised, asking ten consultants, ten non-consultant hospital doctors (NCHDs), ten midwives, ten midwifery students and ten medical students to name the anatomical parts of a 3D model of the clitoris. RESULTS: None of the 50 respondents could name all five labelled parts of the clitoris, and 38 of respondents could not correctly name one anatomical part. CONCLUSIONS: It is evident that there is a lack of knowledge of the anatomical parts of the clitoris among the medical staff included in this study. This reflects a lack of adequate teaching in this area in both past and recent years. Despite this, we acknowledge that women's health and sexual health awareness is improving all of the time, and we hope that this study can highlight the need for reformed teaching in this area.

Anatomic relationships of the clitoral body, bulbs of the vestibule, and urethra.

BACKGROUND: Although recent studies have enhanced our understanding of the anatomy of the clitoris and its somatic innervation, less emphasis has been placed on the anatomic relationships of the clitoris to its surrounding structures. OBJECTIVE: This study aimed to further characterize the gross and histologic relationships of the clitoris, vestibular bulbs, and urethra. STUDY DESIGN: Detailed dissections were performed in 30 unembalmed female cadavers. In 23 specimens, gross dissections were performed, and relationships of the clitoris, vestibular bulbs, and urethra were annotated. Histologic evaluation was performed in 7 specimens, in which tissues were harvested within 24 hours from death. Descriptive statistics were used for data analyses. RESULTS: The clitoral body consisted of 2 components, the proximal body and the distal body. The distal body was oriented ≤90° from the proximal body, forming an outer and inner angle at the inflection point. A "septumlike" arrangement of fibroconnective and vascular tissues was noted between the inner angle of the clitoral body and the urethra. Neurovascular bundles coursed laterally along the clitoral body and the surfaces of the crura and vestibular bulbs. The vestibular bulbs approached each other over the ventral surface of the urethra, at the commissure of the vestibular bulbs. Each bulb was separated by fibrous tissue and did not merge along the midline. The vestibular bulbs approximated the clitoral body, but the erectile tissue of the vestibular bulbs was separated from the corpora cavernosa of the clitoral body by the tunica albuginea. The erectile tissue of the vestibular bulbs abutted the ventrolateral walls of the urethra but was separated from the urethral mucosa by an indiscrete layer of erectilelike tissue with dense stroma. CONCLUSION: This study provided gross and histological confirmation of the relationships of the clitoris, vestibular bulbs, and urethra. Detailed knowledge of the anatomy of the clitoris is crucial for reducing surgical complications associated with periclitoral and distal urethral procedures, which may adversely affect sexual arousal and sexual function.

The complexity of female orgasm and ejaculation.

The anatomy and physiology of the female orgasm are often neglected. The female orgasm is a normal psychophysiological function to all women, and some even can achieve ejaculation as part of the normal physiological response at the height of sexual arousal. The complexity of female sexuality requires a deep understanding of genital anatomy. The clitoris is the principal organ for female pleasure. The vaginal stimulation of the anterior vaginal wall led women to orgasm due to the stimulation of the clitourethrovaginal complex and not due to stimulation of a particular organ called the G spot in the anterior distal vaginal wall. Female ejaculation follows orgasm. It consists of the orgasmic expulsion of a smaller quantity of whitish fluid produced by the female prostate. Squirting can be differentiated from female ejaculation because it is the orgasmic transurethral expulsion of a substantial amount of diluted urine during sexual activity, and it is not considered pathological. The female orgasm is influenced by many aspects such as communication, emotional intimacy, long-standing relationship, adequate body image and self-esteem, proper touching and knowledge of the female body, regular masturbation, male sexual performance, male and female fertility, chronic pain, and capacity to engage in new sexual acts. Stronger orgasms could be achieved when clitoral stimulation, anterior vaginal wall stimulation, and oral sex is involved in the same sexual act.

Clitoral Anatomy in the Feminist Literature: Vagina obscura: An anatomical voyage (2020) and Clitoral Conventions and Transgressions: Graphical representations in anatomy texts, c1900-1991 (1995).

O'Connell et al. proposed that the vestibular bulbs be renamed the "clitoral bulbs" because of their consistent relationship to the clitoris and inconsistent relationship to the vestibule. Normally such proposed esoteric changes in anatomical nomenclature would get little notice by anatomists, yet alone the general public; however, many subsequent articles and books placed this change in the context of centuries of male anatomists and physicians downplaying female sexual anatomy and sexuality. Most prominent is a 2022 book by Rachel Gross, Vagina Obscura: An Anatomical Voyage. Here we review this "Anatomical Voyage" and find author bias in omitting/including erroneous facts in this book. We also present a critique of a 1995 article that appeared in Feminist Studies; Graphical Representations in Anatomy Texts, c1900-1991. This article, which has been repeatedly cited in the clinical literature, asserts that between circa 1950-1980 anatomy textbooks purposely eliminated depicting/labeling the clitoris in illustrations because the authors of the textbooks were reflecting societal norms that de-emphasized the importance of the clitoris. Unfortunately, the methods used by Moore and Clarke are not replicable; and further, their conclusions were not justified because of clear bias in their description and depiction of the anatomy sources they review.

What is a vulva?

What exactly is a vulva? The question remains unresolved. Some sources consider the clitoris, labia, mons pubis, perineum, or vagina to be components of the vulva, while other sources do not. Indeed, disagreement exists among international anatomical and clinical societies with regard to what precise structures form the human vulva. The obfuscation regarding the anatomy of the vulva and, likewise, inconsistencies in vulva-related anatomical terminology have adversely affected communication, research, and healthcare. Therefore, this review was undertaken to provide a comprehensive and critical analysis regarding the past, present, and potential future of vulvar anatomy and vulva-related anatomical terminology. The review reveals that confusion regarding the specific gross anatomical structures that form the vulva has persisted for thousands of years. The review provides novel information regarding the etymology of vulva, contributes important historical context regarding vulva, and gives details regarding related anatomical terminology including clitoris, hymen, labia majora, labia minora, mons pubis, pudendum, pudendum femininum/muliebre, uterus, vagina, et cetera. The review highlights disagreement regarding what specific structures comprise a vulva, identifies sexual bias in anatomical terminology and among noteworthy anatomical resources, and offers novel perspectives regarding anatomical terminology-especially anatomical terminology that relates to the external genitalia. What specific anatomical structures comprise the vulva? This review provides a comprehensive and critical analysis regarding the past, present, and potential future of vulvar anatomy and vulva-related anatomical terminology.

3D quantitative analysis of normal clitoral anatomy in nulliparous women by MRI.

INTRODUCTION AND HYPOTHESIS: We present a 3D computational approach for automated clitoral measurements. We hypothesized that computationally derived measurements would be comparable and less variable than reported manual measures. METHODS: In this retrospective study, MRIs of 22 nulliparous women age 20-49 years with normal vaginal and clitoral anatomy were collected. Manual segmentations were performed to reconstruct 3D models of the whole clitoris (glans, body, crura, and bulbs) and vagina. The length, width, and volume of the clitoral structures and the distance between the vagina and clitoral structures were calculated. Computed clitoral morphometrics (length, width) were compared to median [range] values from a previously published cadaver study (N = 22) using the median test and Moses extreme reaction test. Calculated distances were compared to mean (± SD) reported by a 2D MRI study (N = 20) using independent t-test and Levene's test. RESULTS: Overall, computed clitoral morphometrics were similar to manual cadaver measurements, where the majority of length and width measures had ~1-2 mm difference and had less variability (smaller range). All calculated distances were significantly smaller and had smaller SDs than manual 2D MRI values, with two-fold differences in the means and SDs. Large variation was observed in clitoral volumetric measures in our cohort. CONCLUSIONS: The proposed 3D computational method improves the standardization and consistency of clitoral measurements compared to traditional manual approaches. The use of this approach in radiographic studies will give better insight into how clitoral anatomy relates to sexual function and how both are impacted by gynecologic surgery, where outcomes can assist treatment planning.

The anatomical measurements of vulva in Indian women: A cross-sectional prospective study.

OBJECTIVE: To measure the anatomical dimensions of the vulva in adult Indian women. To analyze their correlations with age, body mass index (BMI), parity, and mode of delivery. METHODS: This cross-sectional study was conducted in a tertiary care university hospital in India, among 400 women aged 18 years and above. Various vulval measurements were taken, and Pearson's correction was applied to variables like age, BMI, parity, and mode of delivery. RESULTS: Mean length of glans of clitoris was 5.2 ± 1.43 mm, the labia minora width was 2.6 ± 0.74 cm, length of introitus was 1.3 ± 0.59 cm, and perineal body length was 2.3 ± 0.60 cm. The range of some measurements was extensive, for example labia minora width ranged from 0.7 to 4.9 cm. Normal centile curves were constructed for vulval measurements according to age groups. Statistically significant positive correlations of age, BMI, and obstetrical history were seen with labia minora width (r = 0.165, P = 0.001; r = 0.284, P < 0.001; r = 0.246, P < 0.001, respectively). CONCLUSION: The centile curves can be used as a reference for the Indian population of different ages. These can be used when counseling women coming for female genital cosmetic surgery.

Anatomical study of the clitoris and its implications on female genital mutilation and surgical repair.

BACKGROUND: Worldwide, 200 million girls and women have been subjected to female genital mutilation. To restore the clitoral function and vulvar anatomy, clitoral repair has been performed since the 2000s. Nevertheless, there is a lack of precise and comprehensive data on the clitoral anatomy during surgical repair. This study aimed to precisely describe the terminal anatomies of the dorsal nerve and artery of the clitoris, and the clitoral neurovascular flap advancement for reconstruction in patients with female genital mutilation. METHODS: This study was performed on seven fresh female cadavers. The site of origin, diameter, length, and trajectory of each nerve and artery were recorded. The clitoral neurovascular flap advancement was measured after a midline transection of the suspensory ligament was performed and after extensive liberation of the dorsal bundles at their emergence from the pubic rami. RESULTS: At the distal point of the clitoral body, the width of the dorsal nerve and artery was 1.9 ± 0.3 mm and 0.9 ± 0.2 mm, respectively. The total length of the dorsal bundles was 6.6 cm (± 0.4). The midpart of the suspensory ligament was sectioned, which allowed a mean anteroposterior mobility of 2.7 cm (± 0.2). Extensive dissection of the neurovascular bundles up to their point of emergence from the suspensory ligament allowed a mean mobility of 3.4 ± 0.2 cm. CONCLUSION: We described the anatomical characteristics of the dorsal nerve and artery of the clitoris and the mobility of the clitoral neurovascular flap for reconstruction post clitoridectomy. This was done to restore the anatomic position of the glans clitoris while preserving and potentially restoring clitoral function in patients with female genital mutilation.

A first radiotherapy application of functional bulboclitoris anatomy, a novel female sexual organ-at-risk, and organ-sparing feasibility study.

OBJECTIVE: The bulboclitoris (clitoris and vestibular bulbs) is the primary organ responsible for female sexual arousal and orgasm. Effects of radiotherapy on the bulboclitoris are unknown, as its structure/function has yet to be described in radiotherapy, and it overlaps only partially with the external genitalia structure. Our aim was to: describe bulboclitoris structure, function and delineation; compare volume of and dose delivered to the bulboclitoris vs external genitalia; and, compare bulboclitoris-sparing IMRT (BCS-IMRT) to standard IMRT (S-IMRT) to determine reoptimization feasibility. METHODS: Our expert team (anatomist, pelvic radiologist, radiation oncologist) reviewed bulboclitoris anatomy and developed contouring guidance for radiotherapy. 20 female patients with anal cancer treated with chemoradiation were analyzed. Sexual organs at risk (OARs) included the external genitalia and the bulboclitoris. Volumes, dice similarity coefficients (DSCs) and dose received using S-IMRT were compared. Plans were reoptimized using BCS-IMRT. Dose-volume histograms (DVHs) for PTVs and all OARs were compared for BCS-IMRT vs S-IMRT. RESULTS: Bulboclitoris structure, function and delineation are described herein. The bulboclitoris occupies 20cc (IQR:12-24), largely distinct from the external genitalia (DSC <0.05). BCS-IMRT was superior to S-IMRT in reducing the dose to the bulboclitoris, with the greatest reductions in V30 and V40, with no significant changes in dose to other OARs or PTV 1/V95. CONCLUSION: The bulboclitoris can be contoured on planning imaging, largely distinct from the external genitalia. Compared with S-IMRT, BCS-IMRT dramatically reduced dose to the bulboclitoris in anal cancer planning. BCS-IMRT might safely reduce sexual toxicity compared with standard approaches. ADVANCES IN KNOWLEDGE: The structure and function of the bulboclitoris, the critical primary organ responsible for female sexual arousal and orgasm, has yet to be described in the radiotherapy literature. Structure, function and delineation of the bulboclitoris are detailed, delineation and bulboclitoris-sparing IMRT were feasible, and sparing reduces the dose to the bulboclitoris nearly in half in female patients receiving IMRT for anal cancer, warranting further clinical study.

Reference values for the external genitalia of full-term and pre-term female neonates.

BACKGROUND AND OBJECTIVES: Identifying virilisation of the genitalia in female newborns early during the neonatal period is important to diagnose pathologies. However, there is no clear threshold for clitoromegaly or for the anogenital ratio. The objective of this study was to define reference values for the external genitalia of full-term and pre-term female neonates. DESIGN: This was a prospective study of all females born in the study centre between May 2014 and July 2016. Clitoral length and anogenital ratio were measured in 619 newborns with a gestational age of 24+2 to 41+3 weeks during their first 3 days of life. Associations between the values at day 3 and gestational age, birth weight and other newborn characteristics were examined by linear regression. RESULTS: The mean clitoral length at day 3 of life was 3.69±1.53 mm (n=551; 95th percentile, 6.5 mm; maximum, 8 mm), and the mean anogenital ratio was 0.42±0.09 (95th percentile, 0.58). There was no significant variation with gestational age or birth weight, and no significant difference between the results at day 0 and day 3. CONCLUSION: These results suggest that clitoromegaly can be defined as a clitoral length >6.5 mm. Values ≥8 mm should prompt further investigations. An anogenital ratio >0.6 should be considered a sign of virilisation. Since clitoral size does not vary with gestational age or birth weight, clitoromegaly should not be attributed to prematurity.

Anogenital distance in newborn infants conceived by assisted reproduction and natural conception.

RESEARCH QUESTION: Does anogenital distance (AGD) differ in newborn infants conceived through assisted reproduction technology (ART) compared with those conceived naturally? DESIGN: This case-control study looked at anthropometric and anogenital measurements in 247 male and 200 female newborns born after ART (n = 121) or natural conception (n = 326), within 24 h of birth. Anogenital measurements included distance from the centre of the anus to the anterior clitoris (AGDAC) and to the posterior fourchette (AGDAF) in female infants, and from the centre of the anus to the posterior base of the scrotum (AGDAS) and to the anterior base of the penis (AGDAP) in male infants. RESULTS: ART mothers were older, more likely to be nulliparous and delivered by Caesarean section at an earlier gestational week. AGDAS of male infants was approximately twice the AGDAF of female infants (17.6 ± 5.0 versus 9.1 ± 3.6 mm). AGDAF in female infants conceived by ART compared with those conceived naturally was not significantly different (8.8 ± 3.6 versus 9.3 ± 3.6 mm; P = 0.404). AGDAC were also comparable for both groups (27.4 ± 6.3 versus 27.7 ± 7.1 mm; P = 0.770). In male infants, no significant difference was seen between ART and natural conception groups in terms of AGDAS (17.4 ± 4.6 versus 17.7 ± 5.2 mm, P = 0.742) and AGDAP (37.5 ± 6.6 versus 38.0 ± 6.7 mm, P = 0.589). When adjusted for gestational age, weight, length and head circumference, mode of conception was not associated with differences in any of the anogenital measurements. CONCLUSIONS: AGD measurements in infants conceived by ART are no different from those of infants conceived naturally.

Formation, structure, and function of extra-skeletal bones in mammals.

This review describes the formation, structure, and function of bony compartments in antlers, horns, ossicones, osteoderm and the os penis/os clitoris (collectively referred to herein as AHOOO structures) in extant mammals. AHOOOs are extra-skeletal bones that originate from subcutaneous (dermal) tissues in a wide variety of mammals, and this review elaborates on the co-development of the bone and skin in these structures. During foetal stages, primordial cells for the bony compartments arise in subcutaneous tissues. The epithelial-mesenchymal transition is assumed to play a key role in the differentiation of bone, cartilage, skin and other tissues in AHOOO structures. AHOOO ossification takes place after skeletal bone formation, and may depend on sexual maturity. Skin keratinization occurs in tandem with ossification and may be under the control of androgens. Both endochondral and intramembranous ossification participate in bony compartment formation. There is variation in gradients of density in different AHOOO structures. These gradients, which vary according to function and species, primarily reduce mechanical stress. Anchorage of AHOOOs to their surrounding tissues fortifies these structures and is accomplished by bone-bone fusion and Sharpey fibres. The presence of the integument is essential for the protection and function of the bony compartments. Three major functions can be attributed to AHOOOs: mechanical, visual, and thermoregulatory. This review provides the first extensive comparative description of the skeletal and integumentary systems of AHOOOs in a variety of mammals.

Clitoral length in immature and mature captive tufted capuchin (Sapajus spp.) females: A cross-sectional study.

Quantitative data on female external genital morphology are sporadic in the primate literature, and the intraspecific and interfemale variation is especially under investigated (e.g., external clitoris length). Since in most anthropoid primate species female external genitals are relatively small and often hidden, for those species whose external clitoris is described as hypertrophic, external genital resemblance may represent a source of confusion in distinguishing the sexes at a distance. This is the case of both captive and wild tufted capuchin (Sapajus spp.) infants. We provided data on external clitoral length and investigated differences in this trait at different ages in a captive female tufted capuchin population. Since likely allometric growth describes changes in relative dimensions of parts of the body that are correlated with changes in overall size, clitoris length has been analyzed by using body weight as a covariate. We measured clitoral length by adapting a technique developed for spotted hyenas (Crocuta crocuta). Our results suggest that the small body size may be only in part responsible of the perception of long clitoris in female infants, since the clitoris is actually longer in immature females compared to adult ones and its size is inversely related to body weight. While the cross-sectional nature of these data does not allow for conclusive interpretation of the results, we tentatively suggest this phenomenon as a transient male-mimicry by immature females. Our study contributed to the description of normative data in a clitoral trait, thus providing foundation for future studies about causal mechanisms and possible adaptive function(s).

The Clitoris-An Appraisal of its Reproductive Function During the Fertile Years: Why Was It, and Still Is, Overlooked in Accounts of Female Sexual Arousal.

Stimulating the clitoris activates the brain to instigate changes in the female genital tract, namely, the enhancement of vaginal blood flow that increases vaginal luminal pO2 , vaginal transudate (lubrication) facilitating painless penile penetration and partial neutralization of the basal luminal acidic pH, vaginal tenting, and ballooning delaying sperm transport and allowing semen de-coagulation and capacitation (sperm activation) factors to act until arousal ends (often by orgasm induction). All these genital changes taken together are of major importance in facilitating the possibility of reproductive success (and thus gene propagation) no matter how or when the clitoris is stimulated-they reveal its overlooked reproductive function. Of course, also commensurate with these changes, is its activation of sexual pleasure. The clitoris thus has both procreative (reproductive) and recreative (pleasure) functions of equal importance. Clitoridectomy creates not only sexual disability but also a reproductive disability. Clin. Anat. 32:136-145, 2019. © 2019 Wiley Periodicals, Inc.

Anatomy, histology, and nerve density of clitoris and associated structures: clinical applications to vulvar surgery.

BACKGROUND: A precise understanding of structures comprising the female external genitalia is essential in obstetric and gynecologic practice. OBJECTIVE: To further characterize the anatomy, histology, and nerve density of the clitoris and associated structures, and to provide clinical correlations to vulvar surgery. MATERIALS AND METHODS: Unembalmed female cadavers were examined. The length and width of the body, glans, and crura of the clitoris were measured. Distances from the glans to the urethra and from the dorsal surface of the clitoral body to the mid pubic arch were recorded. The path of the dorsal nerve of the clitoris was examined, and the nerve width was measured as it emerged from the lateral surface of crura and at the distal clitoral body. Distances from where the dorsal nerve emerged from the perineal membrane to the posterior surface of the membrane and to mid pubic arch were measured. Connective tissue layers associated with the clitoris were examined. Tissue was harvested from additional unembalmed cadavers, and nerve density of the labia minora, glans, and clitoral body were analyzed. Histological examination was performed on vulvar structures to clarify tissue composition. Descriptive statistics were used for data analyses. RESULTS: A total of 27 cadavers (aged 48-96 years) were examined, 22 grossly and 5 histologically. The median length and width of clitoral body were 29 mm (range, 13-59 mm) and 9 mm (range, 5-14 mm), respectively. The glans was 8 mm (range, 5-12 mm) long and 4 mm (range, 3-10 mm) wide. The length of the crura was 50 mm (range, 25-68 mm), and the width at the anterior portion was 9 mm (range, 2-13 mm). The closest distance from the glans to the urethra was 25 mm (range, 14-37 mm) and from the clitoral body to the mid pubic arch was 29 mm (range, 14-46 mm). The widths of the dorsal nerve at the lateral crura and at the distal clitoral body were 3 mm (range, 2-4 mm) and 1 mm (range, 1-2 mm), respectively. The distance from the dorsal nerve as it emerged from the perineal membrane to the mid pubic arch was 34 mm (range, 20-48 mm) and to the posterior surface of the membrane was 20 mm (range, 8-31 mm). The dorsal nerve and artery of the clitoris coursed adjacent to the medial surface of the inferior pubic ramus surrounded by a dense fibrous capsule adherent to the periosteum. The nerve and artery then coursed deep to dense connective tissue layers, which were contiguous with the suspensory ligament and fascia of the clitoris. Histologic examination revealed the presence of erectile tissue in the clitoral body, crura, and vestibular bulbs, but such tissue was absent in the glans and labia minora. Nerve density analysis revealed statistically significant greater density in the dorsal compared with ventral half of the clitoral body. Although not statistically significant, there was increased nerve density in the distal compared to the proximal half of the labia minora. CONCLUSION: Precise knowledge of clitoral anatomy and associated neurovascular structures is essential to safely complete partial vulvectomies, clitoral and vulvar reconstructive procedures, anti-incontinence surgeries, and repair of obstetric lacerations. Understanding the range of anatomic variations and awareness of the areas of increased nerve density is important during counseling and surgical planning. Although the dorsal nerve of the clitoris courses deep to dense connective tissue layers, inadvertent injury may occur in the setting of deep dissection or suture placement. The dorsal nerve seems most vulnerable with surgical entry or lacerations that extend from the midline of the prepuce to the inferior pubic rami.

Urethral regions with differential tissular composition may underlie urinary continence and voiding function in female rats.

AIMS: To analyze, in female rats, the anatomical and histological features of the urethra and its relationship with the vagina and clitoris, and its innervation. METHODS: Seventeen adult female Wistar rats were used. Gross anatomy and acetylcholinesterase (AchE) histochemistry were performed to describe the urethral features, adjacent structures, and innervation. The histomorphometric characteristics of the urethra were determined in transversal, longitudinal, or coronal sections stained with Masson's Trichrome. RESULTS: The female rat urethra is not a homogeneous tubular organ. The pre-pelvic and pelvic regions are firmly attached to the vagina with belt-like striated fibers forming a urethra-vaginal complex. The bulbar regions have curved segments and a narrow lumen. The clitoral region is characterized by a urethra-clitoral complex surrounded by a vascular plexus. The lumen area and thickness of the urethral layers significantly varied between regions (P < 0.05). Innervation of the urethra arrives from the major pelvic ganglion, the dorsal nerve of the clitoris (DNC), and the motor branch of the sacral plexus (MBSP). CONCLUSIONS: Differential tissular composition of the urethra may underlie urinary continence and voiding dysfunction through different physiological mechanisms. The urethra-vagina complex seems to be the main site controlling urinary continence through active muscular mechanisms, while the bulbar urethra provides passive mechanisms and the urethra-clitoris complex seems to be crucial for distal urethral closure by means of a periurethral vascular network.

New approach to the evaluation of perineal measurements to predict the likelihood of the need for an episiotomy.

INTRODUCTION AND HYPOTHESIS: Episiotomy is performed selectively during vaginal delivery. Among the maternal anthropometric factors for episiotomy, the length of the perineal body (pb) and genital hiatus (gh) defined as per the POP-Q system have been studied. The objective of our study was to compare two perineal measurements (defined as per the POP-Q system and the anogenital distance [AGD] concept) to determine which of these can predict the likelihood of an episiotomy being performed. METHODS: An observational prospective cohort study was designed. Anthropometric data (pb, gh, symphysis-coccyx distance, distance between ischial tuberosities, AGDaf [anus-fourchette], and AGDac [anus-clitoris]), duration of the second stage of labor, and neonatal biometric data were collected from 119 women included in this study. Statistical analysis was performed using Student's t test for unpaired data, Mann-Whitney, and Chi-squared tests. Receiver operating characteristic (ROC) curves were generated to compare AGDaf, AGDac, and "gh + pb" with the presence of episiotomy. RESULTS: A shorter "gh + pb" length and AGDac were risk factors for episiotomy. Compared with AGDac, gh + pb was a slightly better predictor in ROC curve analysis. Furthermore, a longer duration of second-stage labor was evident in the episiotomy group. CONCLUSIONS: This study introduces measures of AGD as risk factors for episiotomy. We propose that "gh + pb" length <77 mm and AGDac <93 mm may predict the likelihood of requiring episiotomy and may be useful for diminishing subjectivity in the decision to perform an episiotomy.

Anogenital distance is determined during early gestation in humans.

STUDY QUESTION: Does cord blood androgen level obtained at birth affect the AGD in human newborns? SUMMARY ANSWER: In human newborns, though males have a significantly longer AGD compared to females (as early as 22 weeks of gestation) the AGD is not affected by androgen levels at birth in both the sexes. WHAT IS KNOWN ALREADY: Animal studies have reported a critical time period in early fetal life, termed the masculinization programming window (MPW) during which AGD is fixed by in utero androgen action and is unaffected by testosterone levels later during gestation. Thus, AGD may serve as a lifelong biomarker of androgen exposure during this window. This MPW is hypothesized to occur in humans at 8-14 weeks of gestation during which AGD is fixed. The effect of androgens (testosterone) on AGD after the MPW in humans is not known. Furthermore, altered AGD has been associated with various human reproductive health disorders in both males and females. STUDY DESIGN, SIZE, DURATION: A prospective descriptive cohort study was performed using data from randomly selected neonates (n = 205) born at a single center over a period of 1 year (August 2015 to August 2016). PARTICIPANTS/MATERIALS, SETTING, METHODS: AGDs in male (n = 117) and female infants (n = 88) together with penile width, glans girth and stretched penile length were measured by trained caregivers. Gestation ranged from 22 to 41 weeks and infants were examined within 24 h of birth (within 48-72 h in very sick preterm infants after clinical stabilization). AGD-1 was measured from the center of the anus to the posterior base of scrotum in males or to the posterior fourchette in females. AGD-2 was measured from the center of the anus to the anterior base of the penis in males or to the clitoris in females. Sex steroid hormones (testosterone, 17-OH progesterone (17-OHP) and androstenedione) were measured in serum prepared from umbilical cord blood samples taken at birth, using liquid chromatography-tandem mass spectrometry. MAIN RESULTS AND THE ROLE OF CHANCE: Males had a significantly lower gestational age (mean ± SD; 34.6 ± 4.9 versus 36.1 ± 4.1 weeks, P = 0.04), and a significantly longer AGD-1 (mean ± SD; 21.6 ± 6.0 versus 12.7 ± 3.8 mm, P < 0.001) and AGD-2 (41.9 ± 8.7 versus 33.9 ± 7.1 mm, P = 0.004) compared to female infants, respectively. The cord serum testosterone levels were significantly higher for male than female infants [median, interquartile range; 13.0 (7.3, 20.5) versus 4.1 (2.5, 5.9), ng/dl, P < 0.001]. There was no difference in levels of 17-OHP (P = 0.697) or androstenedione (P = 0.601) between the two sexes. On multiple regression analysis after adjusting for potential confounders, none of the AGD's in both males and females correlated with any sex steroid hormonal levels. We also provide normative charts for penile length, penile width and glans girth in preterm and term infants. LIMITATIONS, REASONS FOR CAUTION: No data were collected on family history of genital malformation, infertility or hormonal disorders, parental endocrine-disrupting chemical exposure or diet pattern, any of which might have influenced the AGD and/or sex steroid hormone levels in the offspring. WIDER IMPLICATIONS OF THE FINDINGS: Our results suggest that AGD in humans, like animals, is fixed in early gestation (likely during the hypothesized MPW) and is unaffected by androgen levels thereafter. Thus, AGD can serve as a biomarker of in utero androgen action during early gestation (likely 8-14 weeks) in humans. As such, causes of human newborn and adult reproductive health disorders, such as endocrine disruptors, should be explored during early gestation. However, further larger studies are needed to help corroborate these findings. STUDY FUNDING/COMPETING INTERESTS: No specific funding was obtained for this study, and all authors have no conflict of interest to declare.