Anatomy of female external genitalia

In this note, we will consider the anatomy of female external genitalia.

These include:

1. Mons pubis (mons pubis)

2. Labia majora (labia majora pudendi)

3. Labia minora (labia minora pudendi)

4. Greater vestibular glands (glandulae vestibulares majores)

5. Lesser vestibular glands (glandulae vestibulares minores)

6. Bulb of the vestibule (bulbus vestibuli)

7. Clitoris (clitoris)

8. Hymen (hymen)

Let’s consider them in greater detail.

The mons pubis (mons pubis) is skin covered with hair.

It is located in the region of the pubic symphysis and the superior branches of the pubis bones.

The mons pubis has a triangular shape with its base directed superiorly with the following borders:

The pubic sulcus (sulcus pubicus), which delimits it from the abdominal region
The pelvifemoral sulci (sulci pelviofemorales), which are the lateral borders

Labia majora (labia majora pudendi) are paired skin folds.

The skin of the external surface of the labia is covered with hair, and it contains a large amount of sweat and sebaceous glands. The thickness of the labia majora is formed by accumulations of subcutaneous fat, inside which venous plexuses and connective tissue septa lie.

Anterior commissure of the labia (commissura labiorum anterior), which is the junction of the labia majora in front.

Posterior commissure of the labia (commissura labiorum posterior), which is the junction of the labia majora from behind.

Posterior commissure of the labia (commissura labiorum posterior)

Rima pudendi (rima pudendi)

It has the following borders:

Anterior commissure of the labia, which is the anterior border
Posterior commissure of the labia, which is the posterior border
Medial surfaces of the labia majora, which are the lateral borders.

The main function of the labia majora is to serve as a barrier between the tissues of the vestibule of the vagina, as well as the vagina and urethra, which open into this vestibule, and the external environment.

In most cases, the labia majora are not a pronounced erogenous zone, unlike the more nerve-rich labia minora.

Labia minora (labia minora pudendi) are paired thin longitudinal skin folds.

They are located interiorly to the labia majora. Their lateral surface adheres to the medial surface of the labia majora. Connective non-adipose tissue with a large number of elastic fibers and venous plexuses form the base of the labia minora.

There are a number of anatomical structures in this region:

The frenulum of the labia minora (frenulum labiorum pudendi), which is a transverse fold that forms when the posterior ends of the labia minora are joined along the median line.

Frenulum of the labia minora (frenulum labiorum pudendi)

The frenulum of the clitoris (frenulum clitoridis), which is the junction of the medial folds of the anterior border of the labia minora attached to the crura of the clitoris.

Frenulum of the clitoris (frenulum clitoridis)

The vestibular fossa of the vagina (fossa vestibuli vaginae), which is a small recess in the posterior part of the vestibule of the vagina.

Vestibular fossa of the vagina (fossa vestibuli vaginae)

The clitoral hood or prepuce of the clitoris (preputium clitoridis), which is the junction of the lateral folds of the anterior border of the labia minora covering the clitoris from above.

Clitoral hood or prepuce of the clitoris (preputium clitoridis)

During childbirth, the labia minora participate in the formation of the outermost portion of the birth canal.

The vestibule of the vagina (vestibulum vaginae), which is a space located anteriorly to the vagina. It has the following borders:

the medial surfaces of the labia minora are the lateral borders;
the clitoris is the anterior border;
the vestibular fossa is the posterior border.

The following orifices open into the vestibule:

1. Vaginal orifice (ostium vaginae)

2. External urethral orifice (ostium urethrae externum), which is located between the vaginal orifice and the clitoris.

3. The ducts of the greater vestibular glands open at the border of the middle and lower thirds of the labia minora.

4. The ducts of the greater vestibular glands open at the border of the middle and lower thirds of the labia minora.

The greater vestibular glands (glandulae vestibulares majores), which are similar to the bulbourethral glands in men. They are also called Bartholin’s glands.

They lie at the base of the labia minora, in the region of their posterior third, 1 cm away from the surface of the mucous membrane. They are paired, pea-sized, and have a tubuloalveolar structure. These glands have their proper excretory duct, which opens on the internal surface of the labia minora, at the border of their middle and inferior thirds.

Their main function is to ensure sexual intercourse that would be painless for a woman. During sexual arousal and sexual intercourse, Bartholin’s glands secrete a brackish viscous mucin-containing and protein-rich liquid, which is transparent with a grayish shade. It maintains normal moisture of the mucous membrane of the vaginal orifice and acts as a lubricant.

The lesser vestibular glands (glandulae vestibulares minores), which are located in the thickness of the labia minora along their medial surface. Their excretory ducts also open there.

They perform the same function as the greater glands.

The bulb of the vestibule (bulbus vestibuli), which is similar to the corpus spongiosum of the penis.

The bulb of the vestibule consists of a dense plexus of veins, which occasionally form cavernous extensions.
The veins are surrounded by connective tissue and bundles of smooth muscle fibers. The middle part is thinned and is located between the external urethral orifice and the clitoris, connecting with the veins of the latter. The lateral part of the bulb is located in the thickness of the labia majora, and its posterior ends adhere to the greater vestibular glands.

The clitoris (clitoris), which is an unpaired organ of the female reproductive system.

It has the following parts:

The corpus cavernosum of the clitoris (corpus cavernosum clitoridis), which is paired and consists of cavernous tissue with small caverns. Externally, they are covered with the tunica albuginea.

Сrura of the clitoris (crus clitoridis), which arise from the periosteum of the inferior pubic rami.

Сrura of the clitoris (singular - crus clitoridis)

They have a cylindrical shape and connect inferiorly to the pubic symphysis, forming the body of the clitoris (corpus clitoridis)

The head of the clitoris (glans clitoridis), which is the anterior free end of the clitoris

The body of the clitoris (corpus clitoridis),

which is covered with the proper fascia of the clitoris (fascia clitoridis)

Proper fascia of the clitoris (fascia clitoridis)

The suspensory ligament of the clitoris (lig. suspensorium clitoridis) is directed from the pubic symphysis to the body of the clitoris

Suspensory ligament of the clitoris (lig. suspensorium clitoridis)

The clitoral hood or prepuce of the clitoris (preputium clitoridis), which is a fold of skin covering the clitoris superiorly. It is a derivative of the labia minora.

The frenulum of the clitoris (frenulum clitoridis), which is located inferiorly to the head and is also a derivative of the labia minora.

The clitoris acts as the main sensitive erogenous zone.

The hymen (hymen) is a thin connective tissue plate covered with a stratified squamous epithelium located between the vagina and its vestibule. It protects the vagina from the environmental microbial flora.

It may have the following shapes:

A semilunar hymen (hymen semilunaris), which is the most common.
An imperforate hymen (hymen imperforatus), which is a rare shape.
A semicircular hymen (hymen semicircularis).

After the first sexual intercourse, the hymen ruptures, and its remnants are known as hymenal caruncles (carunculae hymenales).

Blood supply

1. the internal pudendal artery (a. pudenda interior), which arises from the internal iliac artery, goes down, exits the pelvic cavity, gives off branches going to the external genitalia, perineum, vagina, and rectum;

The posterior labial branches (rr. labiales posteriores)

2. External pudendal arteries (aa. pudendae externae), which are the branches of the femoral artery (2 or 3 thin trunks). One of these arteries goes superiorly and reaches the suprapubic region, branching in the skin; the others approach the labia.

Anterior labial branches (rr. labiales anteriores)

Venous drainage

Blood drains through the eponymous veins.

Anterior labial veins (vv. labiales anteriores), which drain blood into the internal iliac vein.

Posterior labial veins (vv. labiales posteriores), which drain blood into the femoral vein.

Lymph drainage

The lymph mainly drains into the superficial inguinal lymph nodes nodi lymphatici inguinalessuperficiales – nodi lymphatici inguinales profundi – nodi lymphatici iliaci externi – nodilymphatici iliaci communes – nodi lymphatici lumbales – truncus lumbales – cisterna chyli – ductus thoracicus – left venous angle.

Innervation

Afferent innervation is carried out by the pudendal nerve and the nerves of the sacral and lumbar plexuses.
Sympathetic innervation is carried out by branches from the inferior hypogastric plexus.
Parasympathetic innervation is provided by the pelvic splanchnic nerve.

Dictionary