Wilkinson, EJ; Massoll, NA; ,
The external female genitalia include the mons pubis, labia majora and minora, prepuce, frenulum, clitoris, and vestibule. The orifices of the paraurethral (Skene) and Bartholin glands, as well as those of the minor vestibular glands and the urethral meatus, open into the vestibule (Fig.1.1). After menarche, the mons pubis and lateral aspects of the labia majora acquire increased amounts of subcutaneous fat and develop the coarse, curly pubic hair. During adolescence, the labia develop pigmentation and the clitoris undergoes some enlargement. Histologically, the entire vulva, with the exception of the vulvar vestibule, is covered by keratinized, stratified squamous epithelium [245]. The labia majora contain both smooth muscle and fat, whereas the labia minora are devoid of adipose tissue but are rich in elastic fibers and blood vessels [167]. Within the lateral aspects of the labia majora, sebaceous glands are associated with hair follicles but open directly to the surface epithelium toward the medial aspect. Similar sebaceous glands are seen on the perineum posterior to the vestibule. The labia minora typically do not contain glandular elements, except sebaceous glands near the junction with the interlabial sulcus and near the inferior and lateral aspects. The apocrine glands of the labia majora, prepuce, posterior vestibule, and perineal body, like the apocrine glands of the axilla, are activated at menarche, whereas the eccrine sweat glands, primarily involved in heat regulation, function before puberty [189]. The vestibule is bounded medially by the external portion of the hymen ring, posteriorly and laterally by the line of Hart, and anteriorly by the frenulum of the clitoris. The mucosa of the vestibule is glycogenated in women of reproductive age, or under estrogen influence, and resembles vaginal mucosa. The linea vestibularis, seen in approximately one quarter of newborn female infants, is located in the posterior portion of the vestibule, and is a white streak or spot in the midline of the posterior vestibule extending nearly to the posterior commissure [109]. The squamous epithelium of the vestibule merges with the transitional epithelium at the urethral meatus, and with the duct openings of the paraurethral glands (Skene), the major vestibular (Bartholin) glands, and the minor vestibular glands.