DIAPHRAGMS AND LIGAMENTS

PELVIC DIAPHRAGM- Wide but thin muscular layer of tissue that forms the inferior border of the abdomino-pelvic

cavity. - Broad, funnel-shaped sling of fascia and muscle- Extends from the symphysis pubis to the coccyx and from one lateral sidewall to the other. - Primary muscles of the pelvic diaphragm are the levator ani and the coccygeus- A continuous muscle layer encircles the terminal portions of the urethra, vagina, and rectum. - The paired levator ani muscles act as a single muscle and functionally are important in the

control of urination, in parturition, and in maintaining fecal continence. - The pelvic diaphragm is important in supporting both abdominal and pelvic viscera and

facilitates equal distribution of intraabdominal pressure during activities such as coughing.

UROGENITAL DIAPHRAGM (TRIANGULAR LIGAMENT)- Strong, muscular membrane occupying area between the symphysis pubis and ischial

tuberosities and stretches across the triangular anterior portion of the pelvic outlet. - External and inferior to the pelvic diaphragm. - The continuous fascial layer suspend the urethra anteriorly from the pubic bone.- Its free edge is strengthened by the superficial transverse perineal muscle.- Insert posteriorly into the central point of the perineum.- It has two layers that enfold and cover the deep transverse perineal muscle which surrounds

both the vagina and the urethra.- Urogenital diaphragm support the urethra and maintain the urethrovesical junction.- Posteriorly lies the ischiorectal fossa, while superficially lie the bulbocavernosus and

ischiocavernosus muscles.- Found within the diaphragm are the pudendal vessels and nerves, the external

sphincter of the membranous urethra, and the dorsal nerve to the clitoris.

LIGAMENTS- The pelvic ligaments are thickenings of retroperitoneal fascia and consist primarily

of blood and lymphatic vessels, nerves, and fatty connective tissue. - Anatomically called the retroperitoneal fascia subserous fascia, while surgically

called endopelvic fascia.

1. Broad Ligaments- Thin, mesenteric-like double reflection of peritoneum. - Stretching from the lateral pelvic sidewalls and become contiguous with the uterine

serosa.- Though giving minor support to the uterus, within the broad ligaments are found the

following structures: Oviducts; Ovarian and round ligaments; Ureters; Ovarian and uterine arteries and veins; Parametrial tissue; Embryonic remnants of the mesonephric duct, Wolffian body, The mesovarium; and the mesosalpinx.

2. Round ligament- Composed of fibrous tissue and muscle fibers. - It attaches to the superoanterior aspect of the uterus, anterior and caudal to the

oviduct, and runs via the broad ligament to the lateral pelvic wall.

- Crosses the external iliac vessels and enters the inguinal canal, ending by inserting into the labiamajora in a fanlike fashion.

3. Cardinal Ligaments (Mackenrodt’s, ligaments)- Extend from the lateral aspects of the upper part of the cervix and the vagina to the

pelvic wall. - They are a thickened condensation of the subserosal fascia and parametria between

the interior portion of the two folds of peritoneum. - They form the base of the broad ligaments, laterally attaching to the fascia over the

pelvic diaphragm and medially merging with fibers of the endopelvic fascia.- Within these ligaments are found blood vessels and smooth muscle. - The cardinal ligaments help to maintain the anatomic position of the cervix and the

upper part of the vagina and provide the major support of the uterus and cervix.

4. Uterosacral Ligaments- Extend from the upper portion of the cervix posteriorly to the third sacral vertebra. - Thickened near the cervix, they run a curved course around each side of the rectum

and subsequently thin out posteriorly. - The external surface is formed by an inferoposterior fold of peritoneum at the base

of the broad ligaments.- The middle of the uterosacral ligaments is composed primarily of nerve bundles. - Serve a minor role in the anatomic support of the cervix.

CLINICAL CORRELATIONS- The posterior fibers of the levator ani muscles encircle the rectum at its junction

with the anal canal, thereby producing an abrupt angle that reinforces fecal continence. Surgical repair of a displacement or tear of the rectovaginal fascia and levator ani muscles resulting from childbirth is important during posterior colporrhaphy.

- The round ligament is an important surgical landmark in making the initial incision into the parietal peritoneum to gain access to the retroperitoneal space. Direct visualization of the retroperitoneal course of the ureter is an important step in many pelvic operations, including dissections in women with endometriosis, pelvic inflammatory disease, large adnexal masses, broad ligament masses, and pelvic malignancies.

- During pelvic surgery, traction on the uterus makes the uterosacral and cardinal ligaments more prominent. There is a free avasvular space approximately 2 to 4 cm below the superior edge of the broad ligament, and the two sides of the broad ligament are in close proximity. Often gynecologic surgeons utilize this area to facilitate clamping of the anastomosis between the uterine and ovarian arteries