The labia are the major externally visible structures of the vulva. In humans and other primates, there are two pairs of labia: the labia majora (outer lips) are large and thick folds of skin that cover the vulva's other parts, while the labia minora (inner lips) are the folds of skin between the outer labia that surround and protect the urethral and vaginal openings, as well as the glans clitoridis.
In other mammals, the labia majora are not present and the labia minora are instead referred to as the labia vulvae.
Etymology
Labium (plural labia) is a Latin-derived term meaning "lip". Labium and its derivatives (including labial, labrum) are used to describe any lip-like structure, but in the English language, labia often specifically refers to parts of the vulva.
Structure
thumb|upright=1.4|Left: In their resting state, the labia protect the inner areas of the vulva. <br />Right: Spreading the labia apart exposes inner areas of the vulva.<br /> A) [[Labia majora#Commissures|Anterior commissure of labia majora<br /> B) Clitoral hood<br /> C) Labia minora<br /> D) Labia majora<br /> E) Posterior commissure of labia majora<br /> F) Clitoral glans<br /> G) Inner surface of labia majora<br /> H) Vulvar vestibule<br /> I) External urethral orifice<br /> J) Vaginal orifice<br /> K) Fourchette]]
The labia majora are lip-like structures consisting mostly of skin and adipose (fatty) tissue, which extend on either side of the vulva to form the pudendal cleft through the middle. They enclose and protect the other tissues of the vulva. The labia majora often have a plump appearance, and are thicker towards the anterior. The internal surface of the labia minora is a thin moist skin, with the appearance of a mucous membrane. They contain many sebaceous glands, and occasionally have eccrine sweat glands. The labia minora have many sensory nerve endings, and have a core of erectile tissue.thumb|upright=1.8|Labia minora are pronounced differently in different women. This natural variation is completely normal. Depending on the length, the labia minora are visible or completely covered in a standing posture.
Diversity
The color, size, length, and shape of the inner labia can vary extensively from woman to woman. and texturally can vary between smooth and very rugose.
Embryonic development and changes over time
The urogenital folds form the labia minora while the labioscrotal swellings become the labia majora. and sensitivity varies greatly. In some, they are so sensitive that anything other than light touch may be uncomfortable, whereas stimulation may elicit no sexual response in others. The labia may be sexually stimulated as part of masturbation or with a sex partner, such as by fingering or oral sex. Moving the labia minora can also stimulate the extremely sensitive clitoris.
During sexual arousal, the labia majora swell due to increased blood flow to the region, and slightly draw back, revealing the inner labia. The labia minora become engorged with blood, causing them to expand in diameter by two to three times, and darken or redden in color. In those who have had children, the labia majora may also swell significantly during this period, becoming dark red. Continued stimulation can result in an orgasm, and the orgasmic contractions help remove blood trapped in the inner and outer labia, as well as the clitoris and other parts of the vulva, which causes pleasurable orgasmic sensations.
Following orgasm or when no longer sexually aroused, the labia gradually return to their unaroused state.
thumb|Vulva with asymmetric labia minora
thumb|Left: Vulva with pubic hair. Right: Vulva with hair removed by waxing.Views on pubic hair differ between people and between cultures. Some women prefer the look or feel of pubic hair, while others may choose to remove some or all of it. Temporary methods of removal include shaving, trimming, waxing, sugaring and depilatory products while permanent hair removal can be accomplished using electrolysis or laser hair removal. so pornographic images do not depict the full range of natural variations of the vulva. This can lead viewers of pornography to have unrealistic expectations about how the labia should look. Similar to how some women develop self-esteem issues from comparing their faces and bodies to airbrushed models in magazines, women who compare their vulvas to idealized pornographic images may believe their own labia are abnormal. This can have a negative impact on a woman's life, since genital self-consciousness makes it more difficult to enjoy sexual activity, see a gynecologist, or perform a genital self-examination. FGM is mostly outlawed around the world, even in countries where the practice is widespread.
Labiaplasty is a controversial plastic surgery procedure that involves the creation or reshaping of the labia. Labia piercing is a cosmetic piercing, usually with a special needle under sterile conditions, of the inner or outer labia. Jewelry is worn in the resulting opening.
Additional images
<gallery perrow="5">
File:Clitoris outer anatomy.gif|Outer anatomy of clitoris.
File:Close-up of a human female vulva.jpg|Labia majora with partially shaved pubic hair
File:Illu repdt female.jpg|Organs of the female reproductive system.
File:Gray1230.png|Median sagittal section of female pelvis.
File:Labiaminora.jpg|Labia minora visible (with pubic hair)
File:Close Up of a Vagina with Labia Minora open and Clitoris.jpg|Labia minora visible (without pubic hair)
File:Mons, labia and perineum.jpg|Labia with visible mons, perineum and anus (with pubic hair)
File:Vagina collage 14.jpg|Panel showing labia diversity.
File:Differences of vagina with open and closed legs.jpg|Panel showing the same labia with different legs position.
File:Closed Vagina and trimmed public hair.jpg|Closed vagina but one of inner lips visible outside
File:Trimmed and carefully shaved.jpg|Inner lips more visible after trimming / shaving
File:Labia visible from behind.jpg|Longer labia minora are visible from behind when kneeling
</gallery>
See also
- Femalia
- Labia stretching
- Vulva activism