Vulval anatomy

Accompanies the illustrations:

– Vulval Anatomy

– Detailed vulval anatomy

– Detailed vulval anatomy: periclitoral and vestibular structures

What are the structures of the vulva and vulvar vestibule? 

The vulva is the external genitalia and includes the area from mons pubis to buttock, out as far the leg folds / groin, and in as far as the hymen. The vestibule is the area that contains the urethral and vaginal openings, with an outer boundary of Hart’s line.  Hart’s line is the transition from squamous mucosa (non-keratinised squamous epithelium) of vagina and vestibule to hairless skin of labia minora and posterior fourchette.  In some people Hart’s line can be seen and in others it is invisible.

Vulval and vestibular anatomy, from top to bottom

Mons pubis – area of hair bearing skin with fat pad underneath, in front of the pubic bone

Anterior commissure – where the labia majora meet in the midline at the top

Labia majora / outer labia (singular = labium majus) – two folds of hair bearing skin with fat pads underneath that extend from the mons pubis to the buttock, they meet at the anterior commissure at the top and the perineum (also called the posterior commissure) at the bottom

Interlabial fold / sulcus (plural = interlabial sulci) – area between the labia majora and labia minora, a transition from hairless skin to hair bearing skin

Labia minora / inner labia (singular = labium minus) – 2 folds of hairless skin with connective and erectile tissue underneath that protect the vaginal and urethral openings, they divide at the top to form the clitoral hood and the clitoral frenulum

Clitoral hood – a fold of hairless skin that surrounds and protects the glans clitoris, it is formed by the upper division of the labia minora

Glans clitoris – the tip of the body of the clitoris, the only visible part of a much larger structure made up of erectile tissue and nerves covered in hairless skin

Clitoral frenulum – where the lower division of the labia minora join together under the glans clitoris

Urethral meatus / opening – the end of a short muscular tube that carries urine from the bladder to the outside

Skene’s gland openings – also known as paraurethral glands, they produce fluid that helps lubricant the vestibule and urethral meatus

Vaginal opening / distal vagina – the vagina is a muscular canal that extends from the hymen to the cervix (neck of the womb) and is covered in squamous mucosa (non-keratinised squamous epithelium)

Free edge of hymen – soft stretchy tissue that forms a ‘fringe’ and sticks out from the surrounding vestibule and vagina, may become flattened in some places due to trauma or childbirth

Base of hymen – the bottom of the hymen where it connects to the vestibule, an area with many gland openings, nerves, and immune system activity

Minor vestibular glands – small glands that open at the base of the hymen and produce fluid to lubricate the vestibule

Bartholin’s gland openings – also known as major vestibular glands, they open at the base of the hymen at 4 o’clock and 8 o’clock and produce mucinous fluid; if the opening is blocked they can produce a cyst at the lower labia minora

Fossa navicularis – a small triangle between the base of the hymen and the posterior fourchette, often looks shiny and pink-red

Posterior fourchette – the meeting point of the bottom of the labia minora, can be raised or flat, made of hairless skin

Perineum – the area between the vagina and anus where the labia majora meet at the back, the centre is hairless skin and the sides are hair bearing skin

Anus – the opening of the bowel, made of hairless skin transitioning to squamous mucosa (non-keratinised squamous epithelium)

Perianus – the hair bearing skin that surrounds the anus out to 5cm

Natal cleft – the fold between the buttocks

What types of skin are on the vulva and vagina?

There are 3 types of skin that cover the vulva and vagina – 1) hair bearing skin, 2) hairless skin, and 3) squamous mucosa (also called non-keratinised epithelium).  Hair bearing skin is found on the mons pubis, labia majora, lateral perineum, perianus, and buttock.  Hairless skin is found on the clitoris, clitoral hood, clitoral frenulum, labia minora, central perineum, and anal opening.  Squamous mucosa is found at the vestibule, inside the vagina, and inside the anus.

Skin is made up of layers of squamous cells in a constant state of turnover.  Fresh cells are made at the bottom, the cells mature as they move upwards, then cells die and are shed off.  This maturation process is called ‘keratinisation’.  In hair bearing and hairless skin, there is a top layer of dead cells that provides protection to tissues underneath.  In some people the skin cell maturation process doesn’t run smoothly.  This issue contributes to conditions like psoriasis and hidradenitis suppurativa (see Vulval psoriasis and Hidradenitis suppurativa).

Squamous mucosa is different to external skin because it does not have a layer of dead cells on top.  As a result, it is more delicate and absorbs medications more easily.  It also has the most oestrogen receptors.  When there is oestrogen around, vulvovaginal squamous mucosa becomes thicker and more flexible, and the cells contain glycogen that feeds healthy lactobacilli.

Different conditions tend to occur on different skin types.  Some conditions are most common at places where one skin type changes into another skin type, like the cervix, vestibule, and anus.
Are my labia too big (or too small)?

Every person’s vulva is unique.  Just like noses and lips, the vulval structures vary in size, colour, shape, and relative position to other nearby structures.  Most people don’t get a chance to see thousands of vulvas, so they don’t realise how much they vary from person to person.

Medical textbooks, plastic surgery websites, and pornographic movies tend to show a particular type of vulva.  This type of vulva usually has no hair, very small labia minora, light skin with an even tone, and a small round vaginal opening.  Sometimes this look has been achieved with cosmetic surgery and skin bleaching.  This is just one way the vulva can look, and should not be considered ‘ideal’ or ‘normal’.

Some surgeons claim that the labia minora are ‘abnormal’ or ‘hypertrophic’ if they are visible beyond the labia majora.  This is NOT true.  More than half of people with vulvas have labia minora that can be seen outside the labia majora – so this is common, healthy, and natural.  As with any body part, the important thing is that it does its job.  The labia’s job is to protect the sensitive tissues of the clitoris and vagina and to provide pleasure during sexual activity.  If the vulva functions well, there is no need to ‘fix’ it.  If there is pain, itch, discharge, or some other issue, it is best to see doctor or nurse with an interest in vulval and sexual health to find out what might be causing the problem.

It is common for people to feel self-conscious about their vulva.  Sometimes an unsupportive partner makes a cruel comment.  Sometimes people compare themselves to friends or relatives and decide they look different.  How people feel about their vulva may relate to other worries about their body shape, face, weight, or attractiveness.  There are multiple resources available help people struggling with this, including the Labia Library, the Great Wall of Vagina, and the Vulva Gallery.

The vulva changes as people get older, have babies, and take hormonal medications.  After vaginal birth, the vaginal opening may be larger or have a different shape.  The hymen may look different, especially if there was a tear during birth.  The labia and perianus may become darker during pregnancy or with hormonal changes.  After menopause, the labia may become smaller and lighter in colour, especially if there is no oestrogen therapy.  However, menopause should not cause the labia to stick to the side and disappear completely, nor should it cause the clitoral hood to completely flatten and hide the clitoris.  If this occurs, see your doctor or nurse to check if you might have lichen sclerosus or lichen planus (see Lichen sclerosus and Vulvovaginal lichen planus).

There are lumps / bumps on my vulva and the doctor said they are nothing to worry about.  Is that OK?

There are many different lumps and bumps that occur on the skin and do not require any treatment.  Some of these are –

Angioma – small red bumps that are dilated blood vessels near the skin surface

Angiokeratoma – red to purple bumps on the labia majora that occasionally bleed, they are a cluster of tiny blood vessels close to the skin surface

Epidermal cysts or milia – collections of dead skin cells just underneath the skin surface, they are firm white-yellow bumps that sometimes form a head and empty out the contents.  Occasionally they get infected and it is best not to squeeze them.

Fibroepithelial polyp – also known as skin tags, these are soft fleshy projections that may be slightly darker than surrounding skin and sometimes have a stalk

Hymenal caruncle – areas of the hymen that ‘stick out’ a bit more than the rest of the hymen, often due to an area of hymen being displaced during birth

Inclusion cyst – in areas of previous surgery or injury, the skin may heal in a way that blocks off a gland or traps a bit of fluid, producing a small cyst

Lipoma – a smooth round or oval collection of fat cells in the fat layer under the skin, the skin covering it can be moved around

Mole or melanocytic naevus – a flat patch or protruding bump, usually a different colour to the surrounding skin, they stay the same over years and are often present since childhood

Seborrheic keratosis – a brown to grey bump that seems ‘plastered on’ like a sticker, more common as we get older

Vestibular papillomatosis – areas of tiny frond-like skin projections on the inner labia minora and vestibule

Varicosities – dilated veins under the vulval skin, they often occur during pregnancy or after childbirth and look like the ones on the legs

See your doctor if there is a lump or bump that grows, becomes painful, ulcerates, constantly bleeds, or seems to be getting firmer or deeper.  New ‘moles’ should be checked out to make sure they are not something sinister.  Likewise, if there is something that looks like a wart but does not respond to treatment or gets bigger, go see a doctor with an interest in vulval conditions.  In some situations a skin biopsy is needed to determine the diagnosis (see Biopsy).