Week 5.1 - The Pelvic floor

Question 1

How does the pelvic floor contribute to continence?

Answer 1

-Exerts a sphincter action on rectum and vagina

Question 2

What is the pelvic floor composed of?

Answer 2

• Pelvic diaphragm -> levator ani, coccygeus and fascial coverings
• Superficial muscles -> anterior and posterior perineum

Question 3

Describe levator ani

Answer 3

-Paired muscles extending from posterior pubis, obturator internus fascia and ischial spines consisiting of puborectalis, pubococcygeus and iliococcygeus

Question 4

What structures pierce the perineal membrane?

Answer 4

-Urethra/vagina

Question 5

What is the anterior perineum? What does it contain?

Answer 5

• Anterior triangle of the perineum bounded by the pubic symphysis, ischiopubic rami and an imaginary line between the ischial tuberosities
• Contains the deep perineal pouch, perineal membrane, superficial perineal pouch and deep and superficial perineal fascia

Question 6

Where in the perineum are the bulbourethral glands?

Answer 6

-Within the urogenital diaphragm

Question 7

What is the perineal body?

Answer 7

• Fibromuscular junction between anterior and posterior perineum
• Site of attachment for anal sphincter, bulbospongiosus, transverse perineal muscles, levator ani and external urethral sphincter

Question 8

What is the result of damage to the perineal body in women?

Answer 8

-Vaginal prolapse

Question 9

What is the posterior perineum? What does it contain?

Answer 9

• Posterior triangle of the perineum bounded by the coccyx, sacrotuberous ligament and imaginary line between the ischial tuberosities
• Contains the anal apeture, external anal sphincter and ischioanal fossa

Question 10

What is the ischiorectal fossa? What is its clinical significance?

Answer 10

• Fat filled space lateral to anal canal and inferior to pelvic diaphragm which allow expansion of anal canal during defecation
• Infection can track back to the glutes

Question 11

What is the perineum?

Answer 11

-Diamond shaped area below the pelvic diaphragm which is divided into the anterior and posterior triangles by an imaginary line between the ischial tuberosities

Question 12

Name the ‘gaps’ which are present in the pelvic floor

Answer 12

• Urogenital hiatus

- Rectal hiatus

Question 13

What are the functions of the pelvic floor?

Answer 13

• Support the pelvic viscera
• Resistance to increasing intra-abdominal pressures such as coughing
• Urinary and fecal continance

Question 14

What innervates levator ani?

Answer 14

-Pudendal nerve (S2-S4)

Question 15

Describe puborectalis

What is its main function

Answer 15

• U shaped muscle extending from posterior pubis, past urogenital hiatus, around the anal canal
• Maintain position of rectoanal junction and fecal continence (relaxes during defecation

Question 16

Describe pubococcygeus

Answer 16

• Main constituent of levator ani
• Arise from posterior pubis and obturator internus fascia to coccyx and anococcygeal body
• Also surround the vagina or prostate

Question 17

Describe iliococcygeus

Answer 17

-From the ischial spines and obturator internus fascia to coccyx and anococcygeal body

Question 18

Describe coccygeus

Answer 18

• Smallest and most posterior muscle of pelvic diaphragm

- From ischial spines to lateral coccyx/sacrum along sacrospinous ligament

Question 19

What innervates coccygeus?

Answer 19

-S4/S5

Question 20

Primary damage to the pelvic diaphragm leads to what problems?

Answer 20

-Urinary and fecal incontinence

Question 21

What is an episiotomy?

Answer 21

• Mediolateral cut to the perineum to widen the vestibule during childbirth
• Mediolateral cut is more painful in short term but better in ling term -> midline cut risks fecal incontinence

Question 22

State the boundaries of the perineum

Answer 22

• Anterior = pubic symphysis
• Posterior = tip of coccyx
• Lateral = ischial tuberosities
• Roof = pelvic diaphragm
• Floor = skin and fascia

Question 23

What is the purpose of the perineal membrane?

Answer 23

• Site of attachment for superficial external genitalia muscles
• Support the pelvic viscera

Question 24

What is the deep perineal pouch?

Answer 24

-Potential space between the pelvic diaphragm superiorly and perineal membrane inferiorly
(contains the urogenital diaphragm)

Question 25

What is the superficial perineal pouch? What does it contain?

Answer 25

• Located in the anterior perineum
• Potential space between the perineal membrane superiorly and perineal fascia inferiorly
• Contains erectile tissue of penis/clitoris, ischiocavenosis, bulbospongiosus and superficial transverse perineum, and bartholin glands

Question 26

Where is the deep perineal fascia?

Answer 26

-Fascia covering the superficial perineal muscles in the anterior perineum

Question 27

Describe the innervation of the perineum

Answer 27

-Pudendal nerve

-S2,3 and 4 keeps your guts off the floor

Question 28

Describe the levels of endopelvic fascia in women

Answer 28

• Level 1 -> uterosacral ligament supports uterus from above
• Level 2 -> Sheets of fascia at either side of the vagina keep the vagina attached to the side walls
• Level 3 -> Perineal membrane and Perineal body

Question 29

Describe how a weak pelvic floor leads to urinary incontinence

Answer 29

• Normally pressure is exerted on internal urethral sphincter by the pelvic floor muscles in such a way that an increase in intraabdominal pressure is matched by an increase in sphincter pressure = continence
• When the pelvic floor is weak, increase in intraabdominal pressure is not matched by the sphincter and the bladder neck falls through the hiatus -> pressure is not matched by the sphincter = incontinence

Question 30

Describe the effects of childbirth on the pelvic floor

Answer 30

• Stretches/damage to pelvic floor and perineal muscles -> muscle weakness
• Stretches pudendal nerve -> neuropraxia and muscle weakness
• Stretch/rupture of supporting ligaments

Question 32

What is the urogenital diaphragm?

Answer 32

• Located in the deep perineal pouch
• Consists of the deep transverse perineum and sphincter urethrae (external urethral sphincter) between two layers of fascia
• The inferior layer of fascia is the perineal membrane