What is the pelvic diaphragm and what does it do?

The pelvic diaphragm is a muscular floor in the pelvis that separates the true pelvis from the perineum. Its main functions are to support pelvic organs (like the bladder and uterus), provide sphincteric control for the rectum and vagina, and assist in increasing intra-abdominal pressure during activities like defecation or childbirth.

What muscles make up the pelvic diaphragm?

The pelvic diaphragm is primarily composed of two muscles: Levator ani (the major component) and Coccygeus (ischiococcygeus). These muscles are covered by superior and inferior fasciae to form the complete structure.

What openings are found in the pelvic diaphragm?

The pelvic diaphragm has two main openings: Hiatus urogenitalis (an anterior gap for the urethra and vagina) and Hiatus rectalis (a posterior opening for the anorectal junction). These allow passage for organs while maintaining support.

How does the pelvic fascia relate to the pelvic diaphragm?

The pelvic fascia includes layers that cover and support the pelvic diaphragm, such as the superior fascia covering the muscles and a visceral layer around organs. This fascia helps anchor and protect pelvic structures.

What are common clinical issues related to the pelvic diaphragm?

Injuries to the pelvic diaphragm, often from events like difficult childbirth, can lead to problems such as uterine or rectal prolapse and compromised continence. These issues highlight its role in maintaining pelvic stability.

Why is the pelvic diaphragm incomplete anteriorly?

The pelvic diaphragm is incomplete anteriorly to allow passage for essential structures, such as the urethra and vagina, ensuring these organs can function properly while the diaphragm provides surrounding support.

How did the pelvic diaphragm evolve in humans?

In quadrupeds, the muscles of the pelvic diaphragm originally controlled tail movements. In humans, due to upright posture, these muscles have been repurposed to primarily support pelvic organs, adapting to bipedal locomotion.

Pelvic Diaphragm & Fascia – Support of Pelvic Organs

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