Pelvic Floor Anatomy

Question 1

What is the normal position of the pelvic bone?

Answer 1

Vertical (tilted forward)

Question 2

What is the true pelvis?

Answer 2

(lesser! pelvic cavity)

-It is the space between the pelvic inlet and pelvic outlet.

Question 3

What does the pelvic diaphragm separate?

Answer 3

Separates the pelvic cavity from the perineum.

Question 4

What muscle makes up the pelvic diaphragm?

Answer 4

Levator ani

Question 5

What is the only item that goes through the pelvic diaphragm?

Answer 5

Rectum

Question 6

What muscle forms the Obturator Foramen?

Answer 6

Obturator internus

Question 7

What goes through the Obturator internus?

Answer 7

Obturator artery and vein

Question 8

What is the thickening on the wall of the Obturator internus?

Answer 8

Tendinous arch of the Obturator Internus

Question 9

What does the external sphincter consist of?

Answer 9

Fibers from the pelvic diaphragm

Question 10

What is the ischioanal fossa?

Answer 10

Surrounds the Rectum and is a fat-filled space. It is fatty to accommodate the rectum bloating and emptying

Question 11

How can you describe the pelvic diaphragm?

Answer 11

It is a funnel shaped sling

-A “shed roof” having from the tendinous arch of the obturator internus.

Question 12

What is the Tendinous arch of the Obturator Internus?

Answer 12

A thickened region of the deep fascia of the muscle.

Question 13

What does the obturator fascia form?

Answer 13

Obturator fascia also forms the pudendal canal –> pudendal nerve, artery and vein come through after exiting the sciatic foramen

Question 14

What muscles make up the pelvic diaphragm?

Answer 14

• Levator ani

- Coccygeus

Question 15

Where is the Coccygeus found?

Answer 15

On the inside of the sacrospinous ligament

Question 16

What is the order of the Vagina, Urethra and Rectum from front to back?

Answer 16

Urethra, Vagina, Rectum

Question 17

What two muscles is the Levator Ani the collective name for?

Answer 17

• Iliococcygesus muscle

- Pubococcygeus muscle

Question 18

What is the Pubococcygeus muscle often divided into?

Answer 18

1. Puborectalis muscle (puborectal sling)

2. Levator prostatae in males or Pubovaginalis in females

Question 19

Where is the Coccygeus muscle?

Answer 19

It is a slip of muscle that lies on the deep surface of the sacrospinous ligament.
-In dogs this muscle pulls the tail between the legs

Question 20

Where is the puborectal sling and what is its function?

Answer 20

(Puborectalis muscle) encircles the rectum. Normally, the muscle is contracted, kinking the rectum and contributing to sphincteric control.

Question 21

What happens to the Puborectalis muscle during defecation?

Answer 21

The muscle relaxes (parasympathetic, via S2,3,4) allowing the anorectal junction to straighten

Question 22

What is the Urogenital diaphragm?

Answer 22

A little layer of muscle that holds up and in the bladder, reproductive organs.

Question 23

What does the puborectal sling do?

Answer 23

Creates a kink in the rectum. It stops movement of feces through rectum like a kink in a garden hose

Question 24

What state is Puborectalis commonly in? What happens under parasympathetic stimulation?

Answer 24

It is tonically contracted. Under parasympathetic stimulation, during defamation, it relaxes, allowing the anorectal angle to increase (straighten)

Question 25

What does the Puborectal sling act as?

Answer 25

A sphincter itself when contracted.

Question 26

Where does the Coccygeus muscle lie?

Answer 26

Just above the Sacrospinal ligament (from sacrum to the ischial spine/sacrospinal ligament)

Question 27

What makes up the external anal sphincter?

Answer 27

Fibers of the Levator Ani (pelvic diaphragm) blend with the outer longitudinal fibers of the rectum forming a thickened band, the external anal sphincter.

Question 28

How is the internal anal sphincter controlled?

Answer 28

Parasympathetically

Question 29

How is the external anal sphincter controlled?

Answer 29

Voluntarily

Question 30

What forms the lateral muscular wall of the pelvis?

Answer 30

Obturator internus

Question 31

What forms the posterior muscular wall of the pelvis?

Answer 31

Piriformis

Question 32

What does the Ischial spine mark?

Answer 32

• Posterior edge of the levator ani
• Attachment of the coccygeus
• Marks narrowest diameter of pelvis, an important measure in OB

Question 33

What nerve location does the Ischial spine mark?

Answer 33

Pudendal nerve - where it exists the greater sciatic foramen and enters the lesser sciatic formen

Question 34

What identifies where the anesthetic should be deposited for a pudendal block?

Answer 34

Ischial spin (location of pudendal nerve block)

Question 35

What is the only thing that goes through the pelvic diaphragm without support?

Answer 35

Rectum

Question 36

What ligament attaches at the ischial spine?

Answer 36

Sacrospinous ligament

Question 37

What is the action of the pelvic diaphragm?

Answer 37

• Supports the pelvic floor and the organs that pierce it
• Resists outward thrusts accompanying increases in intra-abdominal pressure
• Assists in defecation and urination

Question 38

Portions of the pelvic diaphragm surrounding hollow organs…

Answer 38

…have specialized to become sphincter for that organ.

Question 39

When does Rectal Prolapse occur?

Answer 39

When there is a loss of tone in the muscles that normally create an angle between rectum and anal canal (puborectalis).

Question 40

What things cause Rectal Prolapse?

Answer 40

• Chronic straining to have bowel movements
• Strain during childbirth
• Some neurological disorders
• Disruption of the perineal body, as in episiotomy, may also precipitate rectal prolapse.

Question 41

What is difficult to distinguish between?

Answer 41

Prolapsed internal hemorrhoids and prolapsed rectum - but hemorrhoids are far more common.

Question 42

What two things often occur together?

Answer 42

Internal and external hemorrhoids often occur together.

Question 43

What does rectal prolapse look like?

Answer 43

It has concentric folds of rectal mucosa. It is difficult to distinguish between prolapsed internal hemorrhoids and prolapsed rectum.