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Welcome to the middle.

The little yellow dot below represents the perineum, or perineal body. I like to think of as Grand Central Station - lots of things park here from many different places (bulbo, STP and EAS…as well as DPT which we’ll talk about next post). Because of this, the perineal body has fibers arranged in many different areas which makes it super strong and a perfect place for the pressures pelvic and abdominal cavities to bounce on as we inhale and exhale. It is the keystone of the dome of the pelvic floor.

As with layer one, these muscles are innervated by branches of the pudendal nerve that exit the spine from S2 - S4.

 
 
This is a schematic of the female pelvic floor.  View from Above (looking down, from the diaphragm into the pelvic outlet)  The blue circles represent (from top to bottom), the anus, the vaginal opening and the urethra.

This is a schematic of the female pelvic floor.

View from Above (looking down, from the diaphragm into the pelvic outlet)

The blue circles represent (from top to bottom), the anus, the vaginal opening and the urethra.

 
 

Deep Transverse Perineum

  • Originates from the inner rim of the inferior ischial ramus

  • Inserts at a midline tendinous raphe and the perineal body

  • It stabilizes the perineal body, stabilizes the pelvic floor

Sphincter Urethrovaginalis (Women)

  • Originates from the perineal body

  • Inserts in a loop around the anterior vagina

  • Helps to close the vagina and the urethra

External Urethral Sphincter

  • Originates from the ischiopubic ramus

  • Inserts in a loop around the urethra

  • Helps close the urethra

Female Pelvic Floor Diagram - Middle Layer

Female Pelvic Floor Diagram - Middle Layer

Male Pelvic Floor Diagram - Middle Layer

Male Pelvic Floor Diagram - Middle Layer

 
 

Pelvic Floor Layers, Side View

 
 

Pelvic Floor Layers, View from Above (looking down, from the diaphragm into the pelvic outlet)

 
 

Pelvic Floor Layers, View from Below (looking up at the pelvic floor, from between the legs)