Anatomy- Female Internal Genitalia

Peritoneum - Broad ligament *Mesometrium *Mesosalpinx *Mesovarium

-The broad ligament is the mesentery extending from the lateral sides of the uterus to the medial pelvic cavity wall. It envelops the round ligament, ligament of the ovary, uterine tube, and extends to the ovary. *mesometrium is the part of the broad ligament extending laterally from the body of the uterus. *mesosalpinx is the part that extends superiorly over the uterine tube. *mesovarium is the part that projects posteriorly toward the ovary.

Position of uterus relative to vagina and bladder

-The normal postion is ANTEFLEXED and ANTEVERTED such that it lays on the body of the empty bladder. *anteflexed refers to the anterior curve of the body relative to the cervix. *anteverted refers to the angle between the axis of the cervix and the axis of the vagina.

Veins and Lymph -Veins

A plexus of veins surrounds the uterus and vagina, which drains through uterine/vaginal veins to the internal iliac vein. The lower part of the vagina drains to the perineum to the internal pudendal vein.

Arteries - Anastamoses

Abundant anastamoses exist between uterine, vaginal, and internal pudendal arteries.

Uterus - Body

Body: three layers: endometrium, myometrium, and perimetrium (serosa); and three parts: • FUNDUS- the part of the body "above" the uterine tube. • main part of the body - the majority of the organ; note ligament of the ovary and round ligament of uterus attached near uterine tube. • ISTHMUS - narrow/constricted section inferiorly near the cervix.

Uterus - Cervix

Cervix: conceptually analogous to a sphincter • supravaginal part - subperitoneal, thus no perimetrium but uterovagianal fascia layer; attachment site for fascia (ligament) support of uterus. • vaginal part - projects into lumen of vagina.

Uterus - Internal spaces

Internal spaces (listed from uterine ostium to vagina) • uterine horns (left and right) • uterine cavity (unpaired) • internal os (within isthmus) • cervical canal • external os

Ovaries - Held in place by: *Ligament of the Ovary

LIGAMENT OF THE OVARY - dense connective tissue from the tapered medial border of the ovary to the lateral border of the superior part of the uterus; this is one adult remnant of the embrylogical gubernaculum (the round ligament of the uterus is also).

Veins and Lymph - Lymph overview

Lymphatic drainage is not as might be expected, thus predicting the spread of infection and metastasis from cervical/ovarian cancer is not usually possible.

Uterus - Overview

Note the transition from paired (left and right) structures and single midline organs. An inverted pear-shaped organ that varies in size among individuals and with sexual maturity, pregnancies, and menopause (see figure B3.19 in Moore).

Ovaries - Held in place by: *Suspensory ligament of the ovary

SUSPENSORY LIGAMENT OF THE OVARY - connective tissue covered by fold of peritoneum superio-laterally from ovary to posterior abdominal; contains the ovarian artery and vein as well as autonomics.

Ovaries - overview

Small oval organs suspended in the pelvic cavity near the lateral and posterior walls of the lesser pelvis. The outer surface is the simple cuboidal OVARIAN MESOTHELIUM and is NOT covered by peritoneum; but the ovarian mesothelium is essentially continuous with the peritoneum. (See the Peritoneum section below for details of mesenteries.) Held in place by the following two structures:

Anesthesia for childbirth -Spinal anesthesia -Epidural anesthesia -Pudendal nerve block

The clinical significance: anesthesia for childbirth can be administered in three regions with different effects: • Spinal anesthesia can be injected into the subarachnoid space in lower lumbar regions to anesthetize from the waist down. • Epidural anesthesia can be injected epidurally in the sacral canal to target lower sacral spinal nerve roots. This allows the patient to feel uterine contractions, but anesthetizes the cervix and lower parts of the birth canal with minimal lower limb effects. *Recall that the dural sac encloses the cauda equina only to the S1 vertebral level. • Pudendal nerve block can be targeted (near the ischial spine) to anesthetize only the lower vagina and perineal area. (The pelvic pain line is present on the urinary bladder/ureters, but clinical applications relevant to this pelvic pain line are rarely utilized. The pelvic pain line is NOT present on the rectum.)

Ovaries - Uterine tube

The distal part is the INFUNDIBULUM with fimbriae that envelop the ovary. The opening to the pelvic cavity is the ABDOMINAL OSTIUM. The majority of the uterine tube is the AMPULLA, which narrows proximally as the ISTHMUS. The UTERINE PART of the uterine tube (intramural part) is within the wall of the uterus and opens at the UTERINE OSTIUM. Recall from Histology that there are no clear borders between each part of the uterine tube.

Innervation - Pelvic pain line

The pelvic pain line refers to the border on the uterus where pain either ascends with sympathetics or follows the parasympathetics. This line happens to be where the uterus becomes subperitoneal at the isthmus/cervix.

Innervation -Visceral pain pathway

Visceral pain pathways are slightly different than other organs in a clinically important way: • Pain from ONLY the body and fundus of the uterus follows the sympathetic route to spinal cord levels T12 to L2. Thus the pain of uterine contractions is referred to the low back region. • Pain from the cervix and vagina follow the parasympathetic route to spinal cord levels S2 to S4. • Pain (and general sensation) from the lower ~1/4th of the vagina follows somatic routes via the pudendal nerve, which also arises from S2 to S4. Red=sympathetics Blue=parasympathetics Green= somatic motor (pudendal to skeletal muscle Black=pain sensation

Position of uterus relative to vagina and bladder - Retroflexed and retroverted - Uterine prolapse

• In some females, the uterus can be retroflexed and/or retroverted. A retroverted uterus is more prone to uterine prolapse. • UTERINE PROLAPSE the disposition of the cervix/uterus into the vaginal lumen. The main cause can be defects/trauma to the cardinal ligament (below); but can also be trauma to the pelvic diaphragm or perineal body.

Veins and Lymph -Lymph drainage directions

• Lymph from the fundus, uterine tube, and ovaries drain with the ovarian vein SUPERIORLY TO LUMBAR NODES. • From the fundus/body near the round ligament, lymph flows to SUPERFICIAL INGUINAL NODES (does NOT follow venous drainage!). • From the body of the uterus and cervix, lymph drains to EXTERNAL ILIAC NODES (does NOT follow venous drainage!). • From the cervix and most of vagina lymph drains to INTERNAL ILIAC NODES. Internal and external nodes eventually drain to the lumbar system of nodes/vessels around the aorta/IVC; NOT to the mesenteric system.

Peritoneum - VesicouterinE pouch - Rectouterine pouch

• Other minor folds of peritoneum are present over the uterosacral ligament, ureter, and lateral to the bladder. • vesicouterine pouch - pelvic cavity recess between bladder and uterus; extends inferiorly to isthmus such that the cervix is opposed to the bladder subperitoneally. • rectouterine pouch - pelvic cavity recess between uterus and rectum; extends inferiorly to the FORNIX OF THE VAGINA (an uncommon site for clinical access to the lower pelvic cavity).

Ovaries - Vasculature of ovaries *Ovarian artery *Ovarian vein

• Ovarian artery: from aorta inferior to renal arteries; courses retroperitoneally across psoas to pelvic brim; then through suspensory ligament of the ovary. • Ovarian vein: follows same course to IVC (right) or renal vein (left). • Note ovarian vessels supply/drain distal uterine tube and anastomose with branches of uterine vessels.

Innervation - Sympathetic -Parasympathetic

• Preganglionic sympathetics arise from T12 to L2 and travel down the sympathetic chain to lumbar splanchnics to synapse on small unnamed ganglia in the hypogastric plexus. Postganglionic axons follow the inferior hypogastric plexus to the uterus and vagina as part of the UTEROVAGINAL NERVE PLEXUS along the uterine artery in the cardinal ligament. • Preganglionic parasympathetics arise from S2 to S4 and leave sacral ventral rami as pelvic splanchnics to join the inferior hypogastric plexus and follow the UTEROVAGINAL NERVE PLEXUS to the uterus and vagina. Red=sympathetics Blue=parasympathetics Green= somatic motor (pudendal to skeletal muscle Black=pain sensation

Arteries - Paired structures from left and right internal iliac arteries to the unpaired organs. *Uterine artery

• Uterine artery from internal iliac passes through cardinal ligament at the base of the broad ligament. IMPORTANT CONSIDERATION IN SURGERY- IT PASSES OVER THE URETER. It supplies the fornix region of the vagina, the cervix/uterus and has terminal tubal/ovarian branches. Within the mesosalpinx and mesovarium there are ABUNDANT ANASTOMOSES W/ THE OVARIAN ARTERY. Thus the blood supply to the ovary and uterine tube is redundant.

Arteries - Paired structures from left and right internal iliac arteries to the unpaired organs. *vaGINAL ARTERY *Internal pudendal artery

• Vaginal artery typically arises from the internal iliac, but often from the uterine artery. It runs deep to the ureter, and gives rise to the inferior vesical artery before branching to the vagina. • Internal pudendal artery supplies the inferior vagina/vestibule (as well as other perineal structures).

Vagina 2

• extends through UROGENITAL HIATUS of pelvic diaphragm, where several minor skeletal muscles surround it (medial to the puborectalis muscle); these are superior to the bulbospongiosus and compressor urethrae muscles of the perineum. • VAGINAL ORIFICE is the inferior opening into the vestibule.

Peritoneum - pararectal fossa -paravasical fossa

• pararectal fossa - continuous with the rectouterine pouch in the region of the sacrouterine ligament. • paravesical fossa - lateral to the urinary bladder.

Fascia and Ligment support for uterus -Round ligament of uterus

• round ligament of uterus - remnant of embrylogical gubernaculum; continuous with ligament of ovary; embedded in wall of the body of the utreus; extends to the anterior abdominal wall (through inguinal canal to labia majora).

Vagina

• thin walled structure of smooth muscle/elastic connective tissue. • subperitoneal - surrounded by fascia. • FORNIX is the superior part that surrounds the vaginal part of the cervix; thus the fornix has anterior, lateral and superior parts.

Fascia and Ligment support for uterus -Uterosacral ligament - Cardinal ligament -Broad ligament

• uterosacral ligament - posterior thickening of parietal fascia; from sacrum to cervix. • cardinal ligament (transverse cervical ligament) - lateral thickening of endopelvic fascia; from cervix to tendinous arch of pelvic fascia. *note that the uterosacral ligament is slightly deeper in the lesser pelvis than the cardinal ligament. • broad ligament - pertoneum described below.