Normal Anatomy and Physiology of the Female Pelvis

Mons pubis

The rounded mass of fatty tissue lying over the pubic bone.

Labia majora

The larger outer folds of skin that protect the external genitalia.

Labia minora

The smaller inner folds of skin that protect the vaginal opening.

Clitoris

A small, sensitive organ located at the top of the vulva.

Urethral opening

The external opening through which urine is expelled from the body.

Vestibule of vagina

The area surrounding the vaginal opening.

Bony pelvis

Consists of four bones: two innominate (coxal) bones, sacrum, and coccyx.

True pelvis

The compartment situated inferior to the caudal portion of the parietal peritoneum.

Pelvic cavity

The space within the true pelvis, occupied by various organs.

Perineum

The area below the pelvic floor.

Pelvic diaphragm

The lower margin of the pelvic cavity formed by levator ani and coccygeus muscles.

Rectum

The posterior part of the pelvic cavity occupied by the rectum.

Bladder

An organ that stores urine, located anterior to the vagina and superior to the uterus.

Ureters

Tubes that carry urine from the kidneys to the bladder.

Vagina

A collapsed muscular tube that extends from external genitalia to the cervix of the uterus.

Psoas major

A muscle located in the pelvic sidewall.

Iliacus

A muscle located in the pelvic sidewall.

Piriformis

A muscle forming the posterolateral wall of the pelvis.

Obturator internus

A muscle forming the anterolateral pelvic sidewall.

Levator ani

A muscle forming the pelvic floor (diaphragm).

Coccygeus

A muscle forming the posterior pelvic floor (diaphragm).

Iliopsoas

A muscle formed by the joining of psoas major and iliacus muscles in the false pelvis.

Pubococcygeus

A muscle that is part of the levator ani.

Iliococcygeus

A muscle that is part of the levator ani.

Puborectalis

A muscle that is part of the levator ani.

Vagina

Normally directed upward and backward, forming 90-degree angle with uterine cervix.

Vagina Length

Measures approximately 9 cm in length; is longest along posterior wall.

Vagina Structure

Extends upward and backward from vulva; upper half lies above pelvic floor, lower half lies within perineum.

Vaginal Fornices

Area of vaginal lumen surrounding cervix divided into four fornices.

Vaginal Blood Supply

Arterial supply from vaginal and uterine arteries; drains into internal iliac vein.

Cervix

Projects into vaginal canal.

Endocervix

Cervical canal; communicates with uterine cavity by internal os; vagina by external os.

Exocervix

Continuous with vagina.

Cervical Fornices

Protrudes into upper portion of vaginal canal forming four archlike recesses called fornices.

Cervical Anatomy

Posterior vaginal wall attaches higher on cervix, and fornices are blind pockets formed by inner surface of vaginal walls and outer surface of cervix.

Cervical Space

Is a continuous ring-shaped space with posterior fornix running deeper than its anterior counterpart.

Uterus

Hollow, pear-shaped organ divided into fundus, body, cervix.

Uterine Position

Usually anteflexed and anteverted.

Uterine Support

Supported by levator ani muscles, cardinal ligaments, uterosacral ligaments.

Round Ligaments

Hold uterus in anteverted position.

Uterine Size Premenarchal

1.0 to 3.0 cm long by 0.5 to 1.0 cm wide.

Uterine Size Menarchal

6.0 to 8.0 cm long by 3.0 to 5.0 cm wide.

Uterine Size Multiparity

Increases size by 1.0 to 2.0 cm.

Uterine Size Postmenopausal

3.5 to 5.5 cm long by 2.0 to 3.0 cm wide.

Body of the Uterus

Posterior to vesicouterine pouch and superior surface of bladder; anterior to rectouterine pouch (of Douglas), ilium, colon.

Uterine Cavity Shape

Uterine cavity is funnel-shaped in coronal plane; 'slitlike' in sagittal plane.

Perimetrium

Serous outer layer of uterus; serosa.

Myometrium

Muscular middle layer of uterus composed of thick, smooth muscle supported by connective tissue.

Endometrium

Inner mucous membrane, glandular portion of uterine body.

Broad Ligament

Lateral aspect of uterus to pelvic sidewall.

Mesovarium

Posterior fold of broad ligament; encloses ovary.

Mesosalpinx

Upper fold of broad ligament; encloses fallopian tube.

Round Ligament

Fundus to anterior pelvic sidewalls; holds uterus forward.

Cardinal Ligament

Extend across pelvic floor laterally; firmly supports cervix.

Uterosacral Ligament

Extend from uterine isthmus downward, along side rectum to sacrum; firmly supports cervix.

Suspensory Ligament

Extends from lateral aspect of ovary to pelvic sidewall.

Ovarian Ligament

Extends medially from ovary to uterine cornua.

Anteversion

Most common position; fundus and body bent forward toward cervix.

Dextroversion or Levoversion

Normal variant in absence of pelvic masses.

Retroversion

Entire uterus tilted posteriorly.

Retroflexion

Fundus and body bent backward towards cervix.

Fallopian Tubes

Infundibulum: Funnel-shaped lateral tube projects beyond broad ligament to overlie ovaries; 'free edge' of the funnel has fimbriae.

Ampulla

Widest part of tube where fertilization occurs.

Isthmus

Hardest part; lies lateral to uterus.

Interstitial Portion

Pierces uterine wall at cornua.

Length of Fallopian Tubes

12 cm; blood is supplied by ovarian arteries and veins.

Infundibulum

Funnel-shaped lateral tube that projects beyond broad ligament to overlie ovaries; the 'free edge' of the funnel has fimbriae.

Ampulla

Widest part of the fallopian tube where fertilization occurs.

Isthmus

Hardest part of the fallopian tube; lies lateral to the uterus.

Interstitial portion

Part of the fallopian tube that pierces the uterine wall at cornua.

Ovaries

Almond-shaped structures attached at the posterior aspect of the broad ligament by mesovarium.

Ovarian fossa

The location where the ovaries lie, bounded by external iliac vessels, ureter, and obturator nerve.

Dual blood supply of Ovaries

Receives blood from ovarian artery and uterine artery.

Ovarian vein drainage

Blood drained by ovarian vein into IVC on the right and into renal vein on the left.

Variable Positions of the Ovaries

Ovaries are anterior to internal iliac artery and vein, medial to external iliac artery and vein, and their location is highly variable as ligaments loosen, especially after pregnancy.

Normal Anatomy of Ovaries

Consist of outer layer, or cortex, which surrounds central medulla.

Cortex of Ovaries

Consists primarily of follicles in varying stages of development and is covered by a layer of dense connective tissue, tunica albuginea.

Tunica albuginea

Surrounded by a single, thin layer of cells known as germinal epithelium.

Central medulla of Ovaries

Composed of connective tissue containing blood, nerves, lymphatic vessels, and some smooth muscle at the region of hilum.

Ovarian Hormones

Produce reproductive cell—ovum, and two known hormones: estrogen, secreted by follicles, and progesterone, secreted by corpus luteum.

Functions of Ovarian Hormones

Responsible for producing and maintaining secondary gender characteristics, preparing uterus for implantation of fertilized ovum, and development of mammary glands in females.

Ovarian Ligaments

Ovaries supported medially by ovarian ligaments, originating bilaterally at cornua of uterus.

Suspensory Ligament

Extends from infundibulum of fallopian tube and ovary to sidewall of pelvis.

Pelvic Vasculature

Includes external iliac arteries, external iliac veins, internal iliac arteries, internal iliac veins, uterine arteries, and veins.

Arcuate arteries

Arclike arteries that encircle the uterus in the outer third of myometrium.

Radial arteries

Branches of arcuate arteries that extend from myometrium to the base of endometrium.

Straight and spiral arteries

Branches of radial arteries that supply the zona basalis of endometrium.

Ovarian arteries

Branch laterally off aorta, run within suspensory ligaments and anastomose with uterine arteries.

Ovarian veins drainage

Right vein drains into IVC directly; left drains into left renal vein.

Menstrual Cycle

Female reproductive years begin around 11 to 13 years of age at onset of menses (menstruation) and end around age 50, when menses ceases.

Length of Menstrual Cycle

Approximately 28 days in length, beginning with the first day of menstrual bleeding.

Polymenorrheic Cycle

When the menstrual cycle occurs at intervals of less than 21 days.

Oligomenorrheic Cycle

When the menstrual cycle is prolonged to more than 35 days.

Premenarche

prepuberty

Menarche

menstruating approximately every 28 days

Menopause

cessation of menses

Ovulation

during menarchal years, ovum released once a month by one of two ovaries

Ovulation timing

normally occurs midcycle on about day 14 of 28-day cycle

Ovum release alternation

speculated that ovum release alternates between the two ovaries; one month from right, next month from left

Oocyte development

all ova begin development during embryonic life