Anatomical Relations
The superior fascia of the pelvic diaphragm covers the deep/pelvic surface of the levator ani and coccygeus muscles. It arises from the tendinous arch of levator ani, a thickening on the obturator fascia. Anteriorly, it is attached to the posterior surface of the pubis and extends laterally across the superior pubic ramus. It runs posteriorly along the tendinous arch of levator ani to a point superior to the ischial spine, and blends with the piriformis fascia and anococcygeal ligament.
Medially the superior fascia of pelvic diaphragm blends with the visceral fascia of the pelvic organs, runs in the crura between the organs and contributes to the structures of the endopelvic fascia. Thickenings of the superficial fascia of levator ani at the neck of the bladder make up the medial pubovesical ligament in females and medial puboprosatic ligament in males, which run posteriorly in a slight curve to form the tendinous arch of the pelvic fascia.
Structure
The superior and inferior fasciae of the musculofascial pelvic diaphragm are a part of the two-layered parietal pelvic fascia that separates the pelvic cavity from the perineal structures below. The pelvic diaphragm is concave and made up of elastic fibers which run in the anteroposterior axis; it is thicker than the inferior fascia of the pelvic diaphragm.
Function
The concave superior surface of the pelvic diaphragm is known as the floor of the true pelvic cavity. It supports the pelvic organs, contributes to the reduction intra-abdominal pressure and the regulation of pressure during micturition and defecation.
