Vulva

Pudendum femininum (vulva)

Also known as: external female genitalia, pudendum, labia majora, labia minora, vestibule, mons pubis, hymen

The external female genitalia — mons pubis, labia majora and minora, clitoris, vestibule with the urethral and vaginal openings, vestibular bulbs and glands — which protect the urogenital openings and function in sexual arousal.

Overview

The mons pubis is a fat pad over the pubic symphysis, hair-bearing after puberty. The labia majora are two fat-filled, hair-bearing skin folds (homologous to the scrotum) that meet in front at the anterior commissure; the round ligaments end in them. Inside lie the hairless labia minora, rich in sebaceous glands and vessels, which divide anteriorly to form the prepuce and frenulum of the clitoris and join posteriorly at the fourchette.

The space between the labia minora is the vestibule. It contains the external urethral orifice (≈2–3 cm behind the glans clitoridis), flanked by the openings of the paraurethral (Skene) glands (homologue of the prostate); the vaginal orifice with the hymen; and the openings of the greater vestibular (Bartholin) and lesser vestibular glands. Deep to the labia minora on each side of the vaginal orifice lie the bulbs of the vestibule (erectile tissue, homologue of the penile bulb), covered by bulbospongiosus. The perineal body lies behind the vestibule, between vagina and anus.

Location

Female perineum (urogenital triangle), below the pubic symphysis.

Parts & subdivisions

Mons pubis

Fat pad over the pubic symphysis.

Labia majora

Hair-bearing folds; homologue of the scrotum.

Labia minora

Hairless folds enclosing the vestibule; form the clitoral hood and frenulum.

Clitoris

Erectile organ at the anterior junction of the labia minora.

Vestibule

Contains the urethral and vaginal openings and gland ducts.

Bulbs of the vestibule

Paired erectile masses beside the vaginal orifice.

Greater vestibular glands

Mucous glands opening beside the vaginal orifice.

Anatomy

Innervation

Anterior: ilioinguinal nerve and genital branch of the genitofemoral nerve (L1). Posterior: pudendal nerve (posterior labial and perineal branches, dorsal nerve of the clitoris; S2–S4) and perineal branch of the posterior femoral cutaneous nerve.

Arterial supply

External pudendal arteries (from the femoral artery) anteriorly and internal pudendal arteries (labial, perineal and clitoral branches) posteriorly.

Lymphatic drainage

Superficial inguinal nodes (bilaterally for midline structures), then deep inguinal and external iliac nodes.

Development

Genital tubercle (clitoris), urethral folds (labia minora), labioscrotal swellings (labia majora), urogenital sinus (vestibule).

Clinical significance

Vulval conditions

Lichen sclerosus (white, atrophic, itchy skin; small risk of squamous-cell carcinoma), vulval cancer (usually squamous; HPV-related in younger women; spreads to inguinal nodes), genital warts and herpes, Bartholin cyst/abscess.

Pudendal nerve block

Local anaesthetic infiltrated near the ischial spine anaesthetises most of the perineum for instrumental delivery and perineal repair.

Female genital mutilation

Partial or total removal or injury of the external genitalia for non-medical reasons (WHO types 1–4); causes pain, infection, urinary and menstrual obstruction, sexual dysfunction and obstetric complications, and is illegal in many countries.

Test yourself

The greater vestibular (Bartholin) glands open into the vestibule at approximately which positions?

12 o’clock, beside the clitoris
4 and 8 o’clock, between the hymen and labia minora
On the lateral walls of the upper vagina
Directly into the urethra

Answer: 4 and 8 o’clock, between the hymen and labia minora

Bartholin ducts open posterolaterally (≈4 and 8 o'clock) into the vestibule. Blockage gives a Bartholin cyst; infection gives a painful abscess.