Book 4 - Self Instructional Manual for Cancer Registrars - SEER ...

VaginaThe vagina is situated posterior to the bladder and anterior to the rectum. It extends upward andbackward from the vaginal orifice to the uterus. The vagina is a collapsible tube, capable of greatdistension, composed mostly of smooth muscle lined with a mucous membrane of stratified squamousepithelium and connective tissue (stroma) arranged in rugaek It is about 3 inches (7.5 cm) in length.A fold of mucous membrane, the hymen, forms a border around its external opening in the virginalstate. The functions of the vagina include: 1) receiving semen from the male; 2) serving as the lowerpart of the birth canal; and 3) acting as the excretory duct for uterine secretions and the menstrualflow.The region betweenthe vaginal orifice and the anus is called the perineum.VulvaThe external female genitalia (or vulva) consist of the following structures:• The mons pubis (mons veneris) is a skin-covered pad of fat over the symphysispubis (pubic bone).• Labia majora (large lips) are covered with pigmented skin and hair on the outersurface, smooth and free from hair on the inner surface, and composed mainly offat and glands.• Labia minora (small lips) are Iocated within the labia majora and are covered witha modified skin. (These labia come together anteriorly in the midline, and the areabetween them is called the vestibule of the vagina.)• The clitoris, a small organ composed of erectile tissue located just behind the upperjunction of the labia minora, corresponds in structure to the corpora cavernosa andglans of the penis in the male. The prepuce or foreskin covers the clitoris as itdoes the glans penis in the male.• The urinary (urethral) meatus, the small opening of the urethra located betweenthe clitoris and the vaginal orifice.• The vaginal orifice, the opening into the vagina, located posterior to the urinarymeatus.• Bartholin's glands (greater vestibular glands), two bean-shaped glands, one on eitherside of the vaginal orifice. Each gland opens by means of a single, long duct intothe space between the hymen and the labia minora and corresponds to thebulbourethral glands in the male. They secrete a lubricating fluid.• Skene's glands (lesser vestibular glands) open into the vestibule of the vagina nearthe urinary meatus through two small ducts. They are a group of tiny mucousglands.lrugae--ridges,wrinkles, or folds of mucous membrane.289