Neurology of Sexual and Bladder Disorders

Alessandra Graziottin , Dania Gambini , in Handbook of Clinical Neurology, 2015

The labia minora

The labia minora are two small cutaneous folds 3–4  cm long, situated between the labia majora and extending from the clitoris anteriorly to the fourchette posteriorly (Putz and Pabst, 2008). Anteriorly each labium is divided into two portions: the upper division passes above the glans of the clitoris to fuse with the opposite part and forms the preputium clitoridis; the lower division passes under the clitoris, forming the frenulum of the clitoris with its contralateral part. The labia minora are rich in sebaceous glands, connective tissue, and vascular erectile tissue, with a considerable number of sensory nerve endings and receptors (Netter, 2010).

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The Female Reproductive System

Richard E. Jones PhD , Kristin H. Lopez PhD , in Human Reproductive Biology (Fourth Edition), 2014

Labia Minora

The labia minora ("minor lips") are paired folds of smooth tissue underlying the labia majora. They range from light pink to brownish black in color in different individuals. In a sexually unstimulated condition, these tissues cover the vaginal and urethral openings, but upon sexual arousal they become more open. The hairless skin of the labia minora has oil glands (but no sweat glands) and a few touch and pressure receptors. In older women or in women who have low estrogen levels, the skin of the labia minora becomes thinner and loses surface moisture.

Vestibule

The cavity between the labia minora is the vestibule. Most of this cavity is occupied by the opening of the vagina, the vaginal introitus. In women who have not previously had coitus, the introitus often is covered partially by a membrane of connective tissue known as the hymen. This tissue often is torn during first coitus, accompanied by minor pain and bleeding. However it also can be broken by a sudden fall or jolt, by insertion of a vaginal tampon, or by active participation in such sports as horseback riding and bicycling. In some women, the hymen can persist even after coitus, especially if the tissue is flexible. Thus, the presence or absence of a hymen is not a reliable indicator of virginity or sexual experience. In rare cases, a wall of tissue completely blocks the introitus, a condition called imperforate hymen. The condition is present in about 1 out of 2000 young women. Because an imperforate hymen can block menstrual flow, surgery is required to alleviate the problem.

Urethral Orifice

Anterior to the vaginal introitus is the urethral orifice. This is where urine passes from the body. Below and to either side of the urethral orifice are openings of two small ducts leading to the paired lesser vestibular glands (Skene's glands). These glands are homologous to the male prostate glands (i.e. the two gland types are derived from the same structure in the embryo; see Chapter 5) and secrete a small amount of fluid. At each side of the introitus are openings of another pair of glands, the greater vestibular glands (Bartholin's glands). These glands secrete mucus and are homologous to the bulbourethral glands of the male. Sometimes, Bartholin's glands can form a cyst or abscess as the result of infection.

Clitoris

The glans clitoris lies at the anterior junction of the two labia minora, above the urethral orifice and at the lower border of the pubic bone. The glans is the externally visible portion of the clitoris. Its average length is about 1–1.5  cm (0.5   in) and it is about 0.5   cm in diameter. There is, however, considerable individual variation in clitoral size. This cylindrical structure has a shaft and glans (enlarged end). It is partially homologous to the penis. The clitoral shaft, like the shaft of the penis (Chapter 4), contains a pair of corpora cavernosa, spongy cylinders of tissue that fill with blood and cause the clitoris to erect slightly during sexual arousal (see Chapter 8). At the base of the glans clitoris, the corpus cavernosa tissue branches and each "leg" or crus extends under the surface of the labia minora. Another spongy cylinder present in the penis, the corpus spongiosum, is not found in the clitoris; this tissue in the female is represented by the labia minora (Chapter 5). The clitoral glans is partially covered by the clitoral prepuce, which is homologous to a similar structure covering the glans of the penis (see Chapter 4). The clitoris is rich in sensory receptors. Chapter 8 discusses the role of the clitoris and other structures of the female vulva in the female sexual response.

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Reproductive Medicine

Karel Claes , ... Stan Monstrey , in Encyclopedia of Reproduction (Second Edition), 2018

Clitoro-labioplasty (Vulvoplasty)

In order to achieve the physiologic and aesthetic equivalent of female external genitalia it is imperative to create labia majora and minora, a clitoris and a clitoral hood. The creation of the labia majora is dependent on the use of either a penile flap or a graft, and the amount of scrotal skin remaining after resection. Secondary corrections may be needed and a common secondary correction is symmetrization of the labia majora and sometimes a commisuroplasty with recreation of the anterior commissure covering the neoclitoris (Selvaggi et al., 2005).

Little has been written specifically about the labia minora. Perovic et al. described using the base of the penile skin to form the labia minora, which are then sutured to the deepithelialized area of the neoclitoris. Thus, the neoclitoris is hooded with labia minora ( Perovic et al., 2000). We have used penile foreskin (in continuity with the glans flap for clitoral reconstruction – see below) in order to construct the labia minora and the clitoral hood.

The first person to describe the construction of a neoclitoris was Brown, in 1976. He reported the creation of a functional clitoris using the reduced glans, which remained attached to its dorsal penile neurovascular pedicle (Brown, 1976, 1978). At present, most surgeons performing a clitoroplasty in transsexual patients use the dorsal portion of the glans penis in a horseshoe or W-pattern with the dorsal neurovascular pedicle (Selvaggi et al., 2005; Karim et al., 1995) Dissection of the pedicle can be performed in a plane just above the tunica albuginea of the corpora cavernosa, or in a plane just posterior to this tunica. The latter is a more rapid dissection, but may result in a bulky pedicle and thus an elevated mons pubis.

The clitoral hood and the labia minora can be constructed using a thin inner layer of penile foreskin, which is harvested in continuity with the glans flap. This is the only manner in which the very delicate features of the anterior commissure of the vulva, where the clitoris is located and where the labia minora start from the clitoral hood, can be reconstructed in a natural way (Figs. 9 and 10).

Fig. 9.

Fig. 9. Vaginoplasty—result after 3 months with a detail of the clitoral hood.

Fig. 10.

Fig. 10. Long-term result vagino-clitoroplasty.

The neoclitoris has the ability to swell and cause a climax on erogenous stimulation. In order to achieve swelling of the labia minora as well, we have designed an extended clitoroplasty in which two lateral extensions of the glans penis are placed in the base of the labia minora (unpublished data). Anatomically, this extended neoclitoris mimics better the female clitoral apparatus. The extensions simulate the female corpora cavernosa; cylindrical organs, made of cavernous erectile tissue who are the "hidden" part of the clitoris (Puppo, 2011).

Selvaggi et al. (2005) described the use of the penile urethra to construct the region between the urethral opening and the neoclitoris. The urethra is incised longitudinally along its ventral aspect, folded open, and sutured just inferior to the neoclitoris. This produces a natural appearance, in both color and texture (Fig. 11).

Fig. 11.

Fig. 11. Long-term result vagino-clitoroplasty: labia minora and clitoris.

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Vulva, Vagina, and Anus

Fadi W. Abdul-Karim , ... Bin Yang , in Comprehensive Cytopathology (Third Edition), 2008

Melanomas

These are uncommon malignant tumors of the vulva. 43,44 The most frequent sites of involvement include the labia majora and labia minora. The peak incidence occurs in the sixth through eighth decades of life. The most frequent complaint is that of a mass in the vulvar region accompanied by bleeding or pruritus. Two-thirds of the lesions are pigmented. The superficial spreading type has been reported to be most frequent; however, some have reported that those occurring in mucous membranes were commonly of the lentiginous type. The prognosis correlates with Clark's level and Breslow's depth of invasion. 43 Histologically, atypical melanocytes are noted migrating through the squamous epithelium or into the dermis. The cells occur in loose aggregates that have a nevoid or epithelioid appearance. Nuclear pleomorphism is prominent, with prominent macronuclei. Variable amounts of melanin pigment may be noted. The cytologic appearance of melanoma reveals large pleomorphic cells with varying amounts of isolated or loosely aggregated cytoplasm. The nuclei are enlarged and round to oval. Binucleation and multinucleation are often noted. Macronucleoli are frequent. Intracytoplasmic melanin may be found in the pigmented lesions.

Key features of melanoma in vulvar scrape

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Loose aggregates or isolated cells;

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Cellular and nuclear pleomorphism;

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Enlarged nuclei with macronucleoli;

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Binucleation and multinucleation common; and

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Intracytoplasmic melanin possibly present.

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Newborn Ambiguous Genitalia Management

Charles Sultan , ... Serge Lumbroso , in Encyclopedia of Endocrine Diseases, 2004

Complete Androgen Insensitivity

Complete androgen insensitivity is characterized by an unambiguous female phenotype with a blind vagina pouch and no uterus. Underdevelopment of the clitoris and labia minora may also be observed. The development of an inguinal hernia signals the possibility of complete androgen insensitivity during infancy, whereas this diagnosis is evoked by primary amenorrhea during puberty. However, pubertal breast development is normal or augmented in the majority of cases, in contrast to absent or scanty axillary and pubic hair. Patients with complete androgen insensitivity develop female habitus. The major treatment decision for complete androgen insensitivity syndrome primarily concerns the optional timing of gonadectomy. Our group performs gonadectomy before puberty and prescribes estrogens during puberty.

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Abdomen

S. Jacob MBBS MS (Anatomy) , in Human Anatomy, 2008

Female urethra

The female urethra (Fig. 4.80 ) is about 4cm long, lies on the anterior wall of the vagina and opens in the vestibule between the anterior ends of the labia minora and the clitoris (see Fig. 4.95).

The female urethra is more elastic and more easily distensible than that of the male. Hence catheterisation and instrumentation of the bladder and urethra in the female are more easily performed. As the short urethra opens into the vestibule urinary infection is more common in the female. The sphincter mechanism extends down the whole length of the urethra. Structurally the sphincter is similar to the external sphincter in the male with lissosphincter and rhabdosphincter components which are innervated by the pudendal and autonomic nerves. The sphincter is most well developed in the middle third of the urethra. Unlike in the male the female urethra does not have a well-defined sphincter at the bladder neck.

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Sexual Dysfunction

Lisa Regev , ... William O'donohue , in Encyclopedia of the Human Brain, 2002

III.A.1.b Neurophysiology of the Female

Erectile tissues in females include the vulva, vagina, surrounding vasculature, and the clitoris. During the excitement phase, the clitoris, hidden by the anterior ends of the labia minora, undergoes a vasocongestive response and the labia minora increases in diameter. The dorsal artery of the clitoris is a terminal branch of the internal pudendal artery. The dorsal artery provides the clitoris with its blood supply. Nerves originating from T12–L1 supply the labia majora. The pudental nerve originating from S2–S3 terminates in branches to the glans, corona, and prepuce and is responsible for the innervation of the clitoris. Pelvic vasocongestion results in lubrication, a clear viscuous fluid from the circumvaginal vasculature, and any malfunction in this area results in disorder. Reflex vasodilation, labia and circumvaginal tissue swelling, heightened labial coloring, and lubrication accompany the arousal phase in women.

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Physical Assessment Skills

Karen J. Tietze PharmD , in Clinical Skills for Pharmacists (Third Edition), 2012

Inspection

Inspect sacrococcygeal and perianal areas for lumps, ulcerations, rashes, swelling, external hemorrhoids, and excoriations. Inspect the female external genitalia (mons pubis, labia, perineum, labia minora, clitoris, urethral orifice, and introitus) for abnormalities, including lumps, ulcerations, rashes, swelling, excoriations, and discharge. Inspect the male external genitalia (penis and scrotum) for contour and abnormalities, including lumps, ulcerations, inflammation, excoriations, and swelling.

The female pelvic examination consists of an inspection and palpation (see later discussion). Inspect the vaginal wall and cervix for color, lesions, and the shape of the cervix and cervical os. Note the position of the cervix. Cervical cells may be collected for cytologic evaluation (Papanicolaou [Pap] test).

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Development of the Reproductive System

In Reference Module in Biomedical Sciences, 2014

External Genitalia of Females

In females, the pattern of the external genitalia is similar to the pattern of the indifferent stage (see Figure 16 ). The genital tubercle becomes the clitoris, the genital folds become the labia minora , and the genital swellings develop into the labia majora. The urogenital sinus remains open as the vestibule, into which the urethra and the vagina open. The female urethra, developing from the more cranial part of the urogenital sinus, is equivalent to the prostatic urethra of the male, which has a similar origin. The lack of outgrowth of the clitoris was traditionally considered to result solely from the absence of a dihydrotestosterone influence, but more recent research has also implicated an inhibitory influence of estrogen receptors.

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Androgen Insensitivity Syndrome

Yuan-Shan Zhu , Julianne Imperato-McGinley , in Encyclopedia of Endocrine Diseases, 2004

Clinical Syndrome

Androgen unresponsiveness in utero causes a 46,XY fetus with testes and normal androgen secretion to be born with female genitalia and an absent or severely hypoplastic Wolffian ductal system. The labia, especially the labia minora, may be underdeveloped. The clitoris is normal or small. The vagina ends blindly. Due to normal secretion of anti-Müllerian hormone by the testes in utero, Müllerian-derived structures are absent or rudimentary, and thus the uterus and cervix are absent or rudimentary.

During puberty, there is normal or augmented breast development due to the unopposed estrogenic action by androgens. Pubic and axillary hair is scant or absent.

The testes of patients with complete androgen insensitivity syndrome (CAIS) are usually located in the abdomen or inguinal canal. They cannot be distinguished histologically from those of normal males before puberty. However, postpubertal histologic studies reveal immature tubular development with Sertoli cells, spermatogenia, and no spermatogenesis. There is frequent clumping of tubules with formation of tubular adenomas. Leydig cells are hyperplastic and electron microscopy reveals ample smooth endoplasmic reticulum and mitochondria with tubular cristae. This correlates well with the usually elevated plasma testosterone levels, although in some respects Leydig cells have been reported to resemble fetal Leydig cells with absent crystals of Reinke.

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