Vulva

The vulva refers to the external female genitalia, encompassing the structures visible outside the body. It includes the mons pubis, labia majora, labia minora, clitoris, vestibule, and the external openings of the urethra and vagina. Located in the lower pelvic region, the vulva sits between the thighs and is bounded by the mons pubis at the top and the perineum at the bottom. The vulva forms the outermost part of the female reproductive system and is essential in protecting the internal genital organs. The appearance, shape, and size of the vulva can vary significantly between individuals.

Structure and Anatomy

The vulva is a complex structure that includes various external genital organs, each with distinct anatomical features. Below is a detailed description of the anatomy of the vulva, focusing on its key components.

Mons Pubis

The mons pubis is the rounded, fatty area located at the top of the vulva, covering the pubic bone (pubic symphysis). It sits above the labia majora and clitoris and is covered with pubic hair after puberty. The primary composition of the mons pubis is adipose (fatty) tissue, which provides cushioning and protection to the underlying bone and surrounding structures.

Labia Majora

The labia majora are the larger, outer folds of skin that run down from the mons pubis to the perineum. These folds enclose and protect the inner structures of the vulva. The outer surface of the labia majora is covered with hair and contains sebaceous (oil) and sweat glands, while the inner surface is hairless and smoother. Beneath the skin, the labia majora contain fatty tissue and some smooth muscle fibers, giving them structure and flexibility.

Labia Minora

The labia minora are smaller, thinner folds of skin located just inside the labia majora. Unlike the labia majora, the labia minora do not contain hair and are made up of soft, highly vascularized connective tissue. The inner surfaces of the labia minora are continuous with the mucosal lining of the vaginal opening. These folds vary greatly in size, shape, and color among individuals and converge at the clitoris in the anterior part of the vulva, forming the clitoral hood or prepuce.

Clitoris

The clitoris is a small, highly sensitive organ located at the uppermost part of the vulva, where the labia minora meet. It consists of erectile tissue that becomes engorged with blood during sexual arousal. The external part of the clitoris is called the glans clitoris, which is covered by the clitoral hood (prepuce). Internally, the clitoris extends into the body as the crura and vestibular bulbs, forming a larger structure than what is visible externally.

• Glans Clitoris: The visible, sensitive part of the clitoris, located at the top of the vulva beneath the clitoral hood.
• Clitoral Hood: A fold of skin formed by the convergence of the labia minora, covering and protecting the glans.

Vestibule

The vestibule is the area within the labia minora, extending from the clitoris to the vaginal opening and urethral meatus. This space contains several important structures:

• Urethral Opening (Meatus): Located just below the clitoris within the vestibule, this is the opening through which urine exits the body.
• Vaginal Opening (Introitus): The entrance to the vagina, located just below the urethral opening.
• Bartholin’s Glands: These glands, situated near the vaginal opening, secrete mucus to lubricate the vulva, especially during sexual arousal. The ducts of these glands open into the vestibule near the vaginal entrance.
• Skene’s Glands: Located on either side of the urethral opening, these glands are also involved in lubrication and open into the vestibule near the urethral meatus.

Hymen

The hymen is a thin, membranous tissue that partially covers the vaginal opening in some individuals, especially prior to sexual activity or childbirth. The hymen can vary greatly in appearance and may be present in various shapes, such as crescentic or annular. After rupture or stretching, remnants of the hymen may persist, referred to as the carunculae myrtiformes.

Perineum

The perineum is the area of skin and tissue between the vaginal opening and the anus. This region forms the lower boundary of the vulva and plays a role in supporting the pelvic floor muscles. The perineum is involved in childbirth and is sometimes the site of incisions (episiotomies) to prevent tearing during delivery.

Vestibular Bulbs

The vestibular bulbs are paired masses of erectile tissue located on either side of the vaginal opening, beneath the skin of the vestibule. These bulbs are part of the clitoral complex and swell with blood during sexual arousal, contributing to the engorgement of the vulva.

Blood Supply

The vulva has a rich blood supply, primarily from the internal pudendal arteries, which branch from the internal iliac arteries. These vessels supply the labia, clitoris, and other vulvar structures with oxygenated blood. The veins of the vulva drain into the internal pudendal veins.

Nerve Supply

The vulva is innervated by several nerves, making it highly sensitive to touch, pressure, and temperature. The primary nerves supplying the vulva include:

• Pudendal Nerve: Provides most of the sensory innervation to the vulva, including the clitoris, labia, and perineum.
• Ilioinguinal and Genitofemoral Nerves: Provide additional sensory innervation to the skin of the mons pubis and labia majora.

Lymphatic Drainage

Lymphatic drainage from the vulva is primarily directed to the superficial inguinal lymph nodes, which are located in the groin area. These lymph nodes play a crucial role in filtering lymphatic fluid and are part of the immune defense system of the vulvar region.

Embryological Development

The vulva develops from the genital tubercle and labioscrotal folds during fetal development. These structures form the clitoris, labia, and other external genital components. The development of the vulva is closely linked to the same embryonic tissues that form the male external genitalia, which explains certain structural similarities between male and female external genitalia.

Function

The vulva performs several essential functions related to protection, sexual pleasure, reproduction, and urinary excretion. Below is a detailed explanation of its functions.

Protection of Internal Genitalia

The vulva serves as the outermost barrier, protecting the delicate internal genital structures from external damage, contamination, and infection.

• Labia Majora: The labia majora act as a shield, enclosing the more sensitive structures such as the labia minora, clitoris, and vaginal opening. By covering these areas, they protect the internal genital organs from external irritants, physical trauma, and microbial infections.
• Labia Minora: The labia minora surround the vaginal and urethral openings, providing additional protection by reducing the risk of foreign particles entering these openings. The folds of the labia minora also help retain moisture and provide a natural barrier against bacteria.
• Pubic Hair: The hair on the mons pubis and labia majora helps trap debris and microorganisms, acting as an extra layer of defense against infection and irritation. Pubic hair also reduces friction during movement or sexual activity, helping to protect the sensitive skin of the vulva.

Facilitation of Sexual Pleasure

The vulva plays a central role in sexual pleasure, thanks to its rich supply of nerve endings, especially in the clitoral region.

• Clitoris: The clitoris is the most sensitive part of the vulva, containing thousands of nerve endings that respond to sexual stimulation. Its sole function is to provide sexual pleasure, and during arousal, the erectile tissues in the clitoris swell with blood, enhancing sensitivity and contributing to orgasm. The vestibular bulbs, which are part of the clitoral complex, also swell and contribute to increased sensation.
• Labia Minora: The labia minora contain numerous nerve endings and contribute to sexual pleasure through tactile stimulation. During arousal, the labia minora become engorged with blood, enhancing their sensitivity. The friction or touch on these structures during sexual activity can increase pleasure.
• Vaginal Introitus: The entrance to the vagina, located within the vestibule, plays a role in sexual pleasure by providing sensitivity during penetration. The vestibule’s glands also secrete mucus that helps lubricate the area during arousal, making sexual activity more comfortable and pleasurable.

Lubrication

The vulva is involved in natural lubrication, which is crucial for both sexual activity and maintaining overall genital health.

• Bartholin’s Glands: These glands, located near the vaginal opening, secrete mucus that helps lubricate the vaginal entrance, especially during sexual arousal. This lubrication reduces friction during intercourse, preventing discomfort and potential injury.
• Skene’s Glands: Located near the urethral opening, these glands also contribute to lubrication, particularly around the vestibule. The secretions help keep the urethral area moist and protected from irritation or infection, especially during sexual activity.
• Vaginal Moisture: The mucosal surface of the labia minora and vestibule helps maintain moisture levels, preventing dryness and irritation. This moisture is important for the health of the vulvar skin and reduces the risk of abrasions and infections.

Urination

The vulva includes the external opening of the urethra (urethral meatus), which is involved in the excretion of urine.

• Urethral Opening: The urethral meatus is situated within the vestibule, just below the clitoris. It allows urine to exit the body from the bladder. The proximity of the urethral opening to the clitoris and other structures of the vulva ensures that it remains protected from external contaminants, while still being easily accessible for urination.
• Directing Urine Flow: The anatomy of the vestibule helps guide the flow of urine out of the body and away from the sensitive skin of the vulva. This prevents urine from pooling around the vaginal orifice, reducing the risk of infections and irritation.

Support for Reproductive Functions

The vulva is essential for reproduction, facilitating vaginal penetration, and childbirth.

• Vaginal Opening (Introitus): The vaginal opening provides the entry point for the penis during sexual intercourse, facilitating sperm deposition close to the cervix for potential fertilization. It also serves as the exit point for menstrual blood and, during childbirth, the passage through which the baby is delivered.
• Elasticity and Flexibility: The labia minora and vaginal introitus are highly elastic, allowing them to stretch significantly during sexual intercourse and childbirth. This flexibility is crucial for ensuring comfort during intercourse and for accommodating the passage of a baby through the birth canal.
• Stretch and Engorgement: During sexual arousal, the labia minora and vestibular bulbs become engorged with blood, which increases the elasticity of the tissues. This swelling enhances comfort during vaginal penetration and helps protect the vaginal entrance from tearing.

Menstrual Functions

The vulva plays a role in menstruation, allowing for the exit of menstrual blood from the body.

• Vaginal Opening: The menstrual flow passes through the vaginal canal and exits via the vaginal opening. The labia minora and labia majora help guide the blood away from the body while keeping the area relatively clean and protected.
• Protection During Menstruation: The vulva’s external structure, including the labia, provides some protection to the vaginal opening during menstruation by reducing the risk of contaminants entering the vagina. The pubic hair also helps trap menstrual fluids and provides a barrier against bacteria.

Facilitating Hygiene

The vulva’s anatomical structure aids in hygiene by providing protection to the internal genitalia and helping to direct bodily fluids away from the body.

• Labial Protection: The labia majora and minora protect the openings to the vagina and urethra from dirt, bacteria, and other external contaminants. This protection is important for maintaining hygiene and preventing infections.
• Moisture Regulation: The vulva’s natural lubrication and the presence of glands that secrete protective fluids help regulate moisture levels. This moisture balance prevents the area from becoming too dry, which can lead to cracking or infection, and also helps flush out minor contaminants.

Sensory Function and Tactile Feedback

The vulva is richly innervated, providing tactile feedback and sensory information related to touch, pressure, and temperature.

• Nerve Supply: The vulva contains an extensive network of sensory nerves, primarily the pudendal nerve. This nerve supply makes the vulva highly sensitive to touch, enabling it to respond to physical stimuli. This sensitivity is crucial for sexual pleasure and can also alert an individual to irritation, injury, or infection.
• Tactile Sensation: The vulva’s sensitivity enhances tactile sensations, providing feedback during various activities such as intercourse, urination, or movement. The vulva’s tactile responses help protect it from injury and ensure its proper function in sexual and non-sexual activities.

Thermoregulation

The vulva plays a role in maintaining the temperature of the genital area, protecting the internal reproductive organs.

• Fatty Tissue in Mons Pubis: The adipose tissue in the mons pubis acts as an insulating layer, protecting the underlying pubic bone and internal organs from external temperature changes. This helps regulate the temperature around the genital area, ensuring that the internal reproductive organs remain at an optimal temperature for their functions.
• Pubic Hair: Pubic hair also contributes to temperature regulation by trapping heat in colder environments and providing a barrier against excessive heat or moisture in warmer conditions.

Clinical Significance

The vulva is clinically significant due to its role in various health conditions, including infections, dermatological issues, and sexual dysfunction. Common conditions affecting the vulva include vulvovaginitis, which is inflammation of the vulva and vagina caused by bacterial, fungal, or viral infections. Sexually transmitted infections (STIs) can also affect the vulvar area, leading to symptoms such as itching, pain, and discharge.

Conditions like vulvar vestibulitis or vulvodynia cause chronic pain or discomfort in the vulvar region, impacting sexual activity and quality of life. Additionally, Bartholin’s cysts can form when the ducts of the Bartholin’s glands become blocked, causing swelling and pain near the vaginal opening. Vulvar cancer, though rare, is another significant concern and can present as lesions or unusual growths on the vulva.