S external genitalia

The female external genitalia consist of the following parts, which are collectively referred to as the vulva and have a stratified squamous epithelium:

• Mons pubis. The mons pubis is the rounded prominence over the pubic symphysis, formed by subcutaneous adipose tissue.

• Labia majora. The labia majora are two large longitudinal folds of skin, homologous to the skin of the scrotum, that extend from the mons pubis and form the lateral boundaries of the urogenital cleft. They contain a thin layer of smooth muscle that resembles the dartos muscle of the scrotum and a large amount of subcutaneous adipose tissue. The outer surface, like that of the mons pubis, is covered with pubic hair. The inner surface is smooth and devoid of hair. Sebaceous and sweat glands are present on both surfaces (Fig. 22.30).

• Labia minora. The labia minora are paired, hairless folds of skin that border the vestibule and are homologous to the skin of the penis. Abundant melanin pigment is present in the deep cells of the epithelium. The core of connective tissue within each fold is devoid of fat but does contain numerous blood vessels and fine elastic fibers. Large sebaceous glands are present in the stroma.

• Clitoris. The clitoris is an erectile structure that is homologous to the penis. Its body is composed of two small erectile bodies, the corpora cavernosa; the glans clitoris is a small, rounded tubercle of erectile tissue. The skin over the glans is very thin, forms the prepuce of the clitoris, and contains numerous sensory nerve endings.

• Vestibule. The vestibule is lined with stratified squamous epithelium. Numerous small mucous glands, the lesser

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