External female genitalia
The components of the external female genitalia occupy a large part of the female perineum and collectively form what's known as the vulva. The functions of the external female genitalia are many, such as reproduction and sexual pleasure, parturition and the protection of the internal genital organs.
|Blood supply||Internal pudendal artery|
Anterior labial nerves
Dorsal nerve of the clitoris
This article will take each component separately and provide you with its most significant anatomical aspects.
- Blood supply
- Lymphatic drainage
The mons pubis consists of a mass of subcutaneous adipose tissue anterior to the pubic symphysis, and bears most of the pubic hair.
The labia majora (singular, labium majus) are a pair of thick folds of skin and adipose tissue found inferior to the mons. The fissure between the folds is called the pudendal cleft. Pubic hair can be found on the lateral surfaces of the labia majora once puberty occurs, while the medial/internal surfaces will remain hairless. The round ligament of the uterus passes through the inguinal canal and continues into the labia majora, where the nerve fibers spread and intersperse with the tissue of the mons pubis. The labia majora are thicker in the front where they form by joining the anterior commisure, located inferior to the mons pubis. The posterior commisure of the labia majora is the more inferior joining of the labia majora, and is located above the perineum.
Found medial to the labia majora are the labia minora (singular, labium minus), which are much thinner, devoid of fat and entirely hairless. Their frontal ends split to form upper and lower layers. The upper layer goes superior to the clitoris and forms a fold called prepuce. The lower layer passes inferior to clitoris and forms the frenulum of the clitoris.
The clitoris is an erectile structure, homologue to the male penis, located inferior to the mons pubis at the anterior end of the vulva. Similar to the penis, it is composed of paired crura, a body and glans. Unlike its male counterpart. however, the clitoris is not circumscribed by a foreskin nor is it perforated by the urethra. In addition, most of the clitoris is internal; only its glans is externally positioned.
The clitoris arises as a pair of crura, two erectile structures which attach to the ischiopubic rami. Anteriorly, each crus converges to form the paired corpora cavernosa of the clitoris, which are collectively known as its body and are enclosed in a layer of dense fibrous connective tissue (known as the tunica albuginea). At its distal extremity, the body is surmounted by the glans (head) of the clitoris, which is a small tubercle of erectile tissue that arises from the junction of the vestibular bulbs (mentioned below). Externally, the glans is located between the frenulum of the clitoris anteriorly, and the prepuce of the clitoris posteriorly, which are folds formed by the division of the labia minora. Finally, the clitoris is supported by the suspensory ligament of the clitoris, a fibrous band that connects the clitoris to the pubic symphysis.
In females, the corpus spongiosum is represented as two bodies of erectile tissue in each of the labia minora, referred to as the bulbs of the vestibule or clitoral bulbs.
The labia minora enclose an area called the vestibule, which contains the urinary and vaginal orifices along with the openings of the greater and lesser vestibular glands. The prepuce is found at the anterior margin of the vestibule.
Most females (but not all) are born with a hymen, which is generally in the form of an elliptical/oval-shaped membranous ring around the vaginal orifice (It is generally perforated to some degree, most often in the centre, kind of like a 'donut' shape). The remnants of this membranous ring in adult females in known as hymenal caruncles, which appear as small thin elevations of mucous membrane around the vaginal opening. When the hymen completely covers the vaginal orifice, it is known as an imperforate hymen. An imperforate hymen may rupture naturally during various types of physical activity (aside from intercourse).
Some females may undergo a hymenotomy, which involves the surgical removal, or opening of the hymen, most often to facilitate menstruation, or relieve discomfort during intercourse. This procedure may also be undertaken in the instance when the hymen is abnormally thick, and/or when the opening is small, limiting access to the vaginal orifice.
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Vestibular bulbs are located on each side of the vestibule. They consist of a pair of subcutaneous erectile tissues which correspond to the penile bulb and corpus spongiosum. Both bulbs join in front of urethral orifices under the vestibule of the vagina. Each one is covered with bulbospongiosus muscles.
Bartholin’s (greater vestibular) glands are pea-sized with a short duct that opens into the vestibule or lower vagina. One is found on each side of the vagina. Bartholin’s glands are homologous to the bulbourethral glands in the male, and function to keep the vulva moist, providing lubrication for sexual intercourse during sexual excitement. Additionally, lesser vestibular glands lubricate the vestibule. Finally, a pair of Skene’s (paraurethral) glands, homologous to the male prostate, open into the vestibule nears the external urethral orifice.
More details about the external female genitalia and a clinical case about female genital mutilation are provided below:
Vasculature of the external female genitalia is primarily supplied by the internal pudendal arteries, which are branches of the anterior division of the internal iliac artery.
Lymphatic drainage of the external female genitalia is via the superficial and deep inguinal lymph nodes. Lymph from the clitoris, vestibular bulb and anterior labia minora can alternatively drain into the internal iliac lymph nodes.
The vulva is innervated from a variety of sources. The mons pubis and anterior labia is innervated via the anterior labial nerves, which derive from the lumbar plexus. The posterior aspect of the vulva is innervated via the pudendal nerve and its branches (posterior labial nerves), together with branches from the posterior cutaneous nerve of the thigh. Sensitive innervation to the clitoris is provided by the dorsal nerve of the clitoris.
External female genitalia are part of the female reproductive system, and include:
- mons pubis
- labia majora
- labia minora
- vestibular bulb
- vestibular glands
Vasculature of the external female genitalia is primarily supplied by the internal pudendal arteries, while lymphatic drainage is via the superficial and deep inguinal lymph nodes.
Innervation comes via a variety of sources, such as the anterior and posterior labial arteries and branches of the posterior cutaneous nerve of the thigh.