THE FEMALE REPRODUCTIVE TRACT
April 5, 2010
OBJECTIVES Review the anatomy of the external and
internal female reproductive tract with descriptive illustrations
Provide some clinical correlations, i.e. physiologic changes and implications
THE EXTERNAL FEMALE GENITALIA
VULVA OR PUDENDA
from the mons pubis anteriorly to the rectum posteriorly and from one lateral genitocrural fold to the other
keratinized, stratified squamous epithelium; becomes thicker, more pigmented, and more keratinized as the distance from the vagina increases
Mons Pubis (mons veneris) fat-filled cushion; directly anterior and superior
to the symphysis pubis rounded eminence that becomes hairy after
puberty; escutcheon is triangular, but may vary due to genetic and racial differences A diamond (male) pattern can be found in one of four
women
Labia Majora two large, longitudinal,
cutaneous folds of adipose and fibrous tissue.
approximately 7 to 8 cm in length and 2 to 3 cm in width; extend from the mons pubis anteriorly to become lost in the skin between the vagina and the anus in the area of the posterior fourchette
Skin: pigmented and covered with hair follicles - inner surface does not have hair follicles but has many sebaceous glands.
Usually the labia atrophy after menopause. The labia majora are homologous to the scrotum in the male.
Labia Minora (nymphae) small, red cutaneous folds
situated between the labia majora and the vaginal orifice
more delicate, shorter, and thinner than the labia majora
Divide anteriorly at the clitoris to form the prepuce superiorly and inferiorly the frenulum of the clitoris
Histologically composed of dense connective tissue with erectile tissue and elastic fibers, rather than adipose tissue.
Skin: less cornified and has many sebaceous glands but no hair follicles or sweat glands
relatively more prominent in children and postmenopausal women
homologous to the penile urethra and part of the skin of the penis in males.
Clitoris short, cylindrical, erectile
organ at the superior portion of the vestibule
normal adult glans clitoris has a width less than 1 cm, with an average length of 1.5 to 2 cm
Size affected by previous childbearing NOT age, weight, and oral contraceptive
glans: distal one third; has many nerve endings
consists of a base of two crura, attached to the periosteum of the symphysis pubis;
Body: has two cylindrical corpora cavernosa composed of thin-walled, vascular channels that function as erectile tissue
The clitoris is the female homologue of the penis in the male.
Vestibule the lowest portion of the
embryonic urogenital sinus; the cleft between the labia minora visualized when the labia are held apart
extends from the clitoris to the posterior fourchette
Fossa navicularis posterior portion of the
vestibule between the fourchette and the vaginal opening
Urethra membranous conduit for
urine In females: measures
3.5 to 5 cm in length; distal orifice: 4-6mm in
diameter proximal two thirds:
mucosa composed of stratified transitional epithelium
distal one third: stratified squamous epithelium and the mucosal edges grossly appear everted.
Skene's Glands (paraurethral glands) branched, tubular glands adjacent to the distal
urethra; usually run parallel to the long axis of the
urethra for approximately 1 cm before opening into the distal urethra, or may open into the area just outside the urethral orifice
the largest of the <paraurethral> glands; many smaller glands are also present
homologous to the prostate in the male.
Bartholin's Glands vulvovaginal glands located
beneath the fascia at about 4 and 8 o'clock, on the posterolateral aspect of the vaginal orifice
about the size of a pea; open into a groove between the hymen and the labia minora
Histologically composed of cuboidal epithelium, with ducts lined by transitional epithelium approximately 2 cm in length.
Homologous to Cowper's glands in the male
Vestibular Bulbs two elongated masses of erectile tissue on either
side of the vaginal orifice immediately below the bulbocavernosus muscle;
the distal ends of the vestibular bulbs are adjacent to Bartholin's glands
homologous to the bulb of the penis in the male
Hymen a thin, usually perforated membrane at the
entrance of the vagina variations in the structure and shape of the
hymen
histologically covered by stratified squamous epithelium on both sides, with fibrous tissue and a few small blood vessels
carunculae myrtiformes: tags, or nodules, of firm fibrous material; remnants of the hymen identified in adult females.
Vagina a thin-walled, distensible,
fibromuscular tube that extends from the vestibule of the vulva to the uterus.
The walls of the vagina are normally in apposition and flattened in the anteroposterior diameter; but the potential space of the vagina is larger in the middle and upper thirds.
held in position by the surrounding endopelvic fascia and ligaments
Upper portion close to the horizontal plane
when a woman is standing supported by the upper
portions of the cardinal ligaments and the parametria
Middle portion supported by the levator ani
muscles and the lower portion of the cardinal ligaments
Lower portion in close relationship with
the urogenital and pelvic diaphragms
Rugae numerous transverse folds,
prominent in the lower third, in reproductive age women; provide accordion-like distensibility
Fornices spaces between the cervix and
attachment of the vagina; the posterior fornix is considerably larger than the anterior fornix, thusa anterior vaginal length ~6 to 9 cm posterior vaginal length ~8 to 12
cm
Histology: composed of four distinct layers:
Mucosa: stratified, nonkeratinized squamous epithelium May become keratinized Similar to the exocervix, but has larger and more
numerous papillae does not normally have glands
Lamina propria (tunica): fibrous connective tissue collagen and elastic tissue, with a rich supply of
vascular and lymphatic channels The muscular layer: many interlacing fibers; with an
inner circular layer and an outer longitudinal layer Cellular areolar connective tissue: large plexus of
blood vessels.
VASCULAR SUPPLY Arterial supply: extensive
anastomotic network throughout the vaginal length vaginal artery: originates
either directly from the uterine artery or as a branch of the internal iliac artery
may be multiple on each side of the pelvis
with an anastomosis with the cervical branch of the uterine arteries azygos arteries
Also has contributions from the internal pudendal, inferior vesical, and middle hemorrhoidal
Venous drainage: complex, accompanies the arterial system
Pudendal veins: principal drainage below the pelvic floor
Vaginal, uterine, vesical veins, as well as those around the rectosigmoid, provide drainage of the venous plexuses surrounding the middle and upper vagina
Lymphatics characterized by wide distribution
and frequent crossovers between the right and left sides of the pelvis
Upper third of the vagina: external iliac nodes
Middle third of the vagina: common and internal iliac nodes
Lower third: complex and variable distribution, including the common iliac, superficial inguinal, and perirectal nodes
NERVE SUPPLY The nerve supply of the vagina comes from
the autonomic nervous system's vaginal plexus, and sensory fibers come from the pudendal nerve.
Pain fibers: enter the spinal cord in sacral segments two to four;
With a paucity of free nerve endings in the upper two thirds of the vagina
PERINEUM Pelvic diaphragm
forms the inferior border of the abdominopelvic cavity; composed of a broad, funnel-shaped sling of fascia and muscle
it extends from the symphysis pubis to the coccyx and from one lateral sidewall to the other
the primary muscles of the pelvic diaphragm are the levator ani and the coccygeus
Urogenital Diaphragm also called the triangular ligament; a strong, muscular
membrane that occupies the area between the symphysis pubis and ischial tuberosities
external and inferior to the pelvic diaphragm
suspends the urethra from the pubic bone by continuations of the fascial layers
the free edge of the diaphragm is strengthened by the superficial transverse perineal muscle
inserts posteriorly into the central point of the perineum
Perineal Body the median raphe of the levator ani, between the
anus and the vagina, reinforced by the central tendon of the perineum.
the bulbocavernosus, superficial transverse perineal, and external anal sphincter muscles also converge on the central tendon
CLINICAL CORRELATIONS Susceptibility to infection, especially along the
intertriginous areas
Changes post-menopause
Bartholin’s duct cyst – most common enlarged cyst of the vulva; abscess and urethral diverticula formation
Vulvar trauma, i.e. due to saddle injuries or childbirth and the blood supply
Continuity between the labia majora, mons pubis, and anterior abdominal wall via the subcutaneous tissue
CLINICAL CORRELATIONS The posterior fornix as an important surgical landmark
The distal course of the ureter as an important consideration in vaginal surgery, and the anatomic proximity and interrelationships of the vascular and lymphatic networks of the bladder and vagina
Gartner's duct cyst (cystic dilation of the embryonic mesonephros) vs. large urethral diverticula
Vaginal lubrication during intercourse and the rich vascularization of the organ
The anatomic relationship between the long axis of the vagina and other pelvic organs when altered by pelvic relaxation, i.e. from the trauma of childbirth
Atrophy or weakness of the endopelvic fascia and the development of a cystocele, rectocele, or enterocele. rare complication : massive hemorrhage from the inferior gluteal or pudendal
arteries
REFERENCES Katz et al. (2007). Comprehensive
Gynecology, 5th ed.
Cunningham et al. Williams Obstetrics, 22nd edition.
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