Pelvic Diaphragm and Perineum M1 Perineum SDV

Summary

This video provides an in-depth explanation of the pelvic diaphragm and perineum, two crucial areas of the pelvic floor. It outlines the pelvic diaphragm's key muscle groups, including the levator ani and coccygeus muscles, which support the pelvic organs and resist abdominal pressure. Additionally, it explores the perineum's boundaries and structure, highlighting the urogenital and anal triangles, as well as muscles like the bulbospongiosus and external anal sphincter. Together, these structures support the pelvic region, facilitating bodily functions like urination and defecation while contributing to the support of external genitalia.

Takeaways

• 😀 The pelvic diaphragm consists of muscles that support the pelvic viscera and resist intra-abdominal pressure.
• 😀 The two major muscles of the pelvic diaphragm are the levator ani and the coccygeus muscles.
• 😀 The levator ani muscle extends from the anterior and lateral aspects of the bony pelvis to the posterior and lateral aspects.
• 😀 The puborectalis muscles form a sling around the anorectal junction, causing the rectum to face anteriorly and the anal canal to face posteriorly.
• 😀 The coccygeus muscles run from the ischial spines and connect to the coccyx and the anococcygeal raphe.
• 😀 The iliococcygeus muscles originate from the tendonous arc of levator ani and insert on the coccyx and anococcygeal raphe.
• 😀 The ischiococcygeus muscles are wedge-shaped and attach to the sacrum and coccyx.
• 😀 The perineum is bounded by the ischiopubic rami anterior-laterally and the sacrotuberous ligaments posterior-laterally.
• 😀 The perineum is divided into two triangles: the urogenital triangle (anterior) and the anal triangle (posterior).
• 😀 The urogenital hiatus in the urogenital triangle allows passage for the urethra and vagina, surrounded by the bulbospongiosus muscle.
• 😀 The anal triangle contains the external anal sphincter and is a site where muscles like the bulbospongiosus and transverse perineal muscles converge to form the perineal body.

Q & A

What are the two major components of the pelvic diaphragm?

The two major components of the pelvic diaphragm are the levator ani muscle and the coccygeus muscle.

Where does the levator ani muscle extend from and to?

The levator ani muscle extends from the anterior and lateral aspects of the bony pelvis to the posterior and lateral aspects of the bony pelvis.

Why are some parts of the levator ani muscle not visible?

Some parts of the levator ani muscle are not visible because they are obscured by features of the urogenital triangle, such as the perineal membrane and various muscles like the ischiocavernosus and transverse perineal muscles.

What is the function of the puborectalis muscle?

The puborectalis muscle forms a sling around the anorectal junction, helping to maintain the rectum’s anterior-facing position while the anal canal is posteriorly positioned.

Where do the pubococcygeus muscles originate and insert?

The pubococcygeus muscles originate from the posterior portions of the pubic bones and the ischiopubic rami. They insert into the coccyx and the anococcygeal raphe.

What is the iliococcygeus muscle's origin and insertion?

The iliococcygeus muscle originates from the tendinous arc of the levator ani and inserts into the coccyx and anococcygeal raphe.

What is the role of the coccygeus muscles in the pelvic diaphragm?

The coccygeus muscles are wedge-shaped and extend from the ischial spines to the coccyx, contributing to the support of the pelvic diaphragm.

What defines the boundaries of the perineum?

The boundaries of the perineum include the ischiopubic rami anteriorly, the sacrotuberous ligaments posteriorly, and the coccyx, which separates the urogenital and anal triangles.

What structures are found in the urogenital triangle?

The urogenital triangle contains the urogenital hiatus, through which the urethra and vagina pass. Surrounding this space are muscles like the bulbospongiosus.

What is the perineal body and where is it located?

The perineal body is a site of central support where the muscles of the urogenital and anal triangles converge. It is located between the urogenital and anal triangles and is crucial for structural support.