Lecture 3 - The Pelvic Floor

Question 1

What are the primary functions of the pelvic floor?

Answer 1

1) Support the pelvic organs - vagina, uterus, ovaries, bladder & rectum
2) Maintaining intra-abdominal pressure during coughing, vomiting, sneezing & laughing
3) Facilitate micturition and defection
4) Maintain urinary and faecal continence
5) Facilitate childbirth

Question 2

Where do the pelvic floor run to and from?

What structures run through the pelvic floor?

Answer 2

• Pelvic floor and its muscles runs from the coccyx (posterior) all the way to the pubic bone (anterior)
• Urethra, vagina & anus

Question 3

By what 3 mechanisms do the pelvic floor provide support to the pelvic organs and structures?

Answer 3

1) Suspension
2) Attachment
3) Fusion

Question 4

What is suspension, attachment and fusion provided by?

Answer 4

Suspension = providing vertical support against gravity (like a hammock), via cardinal ligaments (holding cervix & upper vagina in place), uterosacral ligaments (holding back of cervix and upper vagina laterally) & round ligament (maintaining anteverted position)

Attachment = Endopelvic fascia stretches like a hammock, urethra lies anterior and above it and gets compressed against it during increased intra-abdominal pressure, maintaining urinary continence.

Fusion = Involves urogenital diaphragm and perineal body. Vaginal endopelvic fascia fused to perineal body posteriorly, the levator ani laterally and urethra anteriorly

Question 5

What are the main components of the pelvic floor?

Answer 5

1) Levator ani muscles (predominantly)
2) Perineal membrane
3) Perineal body
4) Perineal muscles
5) Posterior compartment

Question 6

Identify & name the 3 levator ani muscles

Describe their origin/insertions and their structure

Answer 6

1) Iliococcygeus (posterior)
2) Pubococcygeus
3) Puborectalis (anterior)

• Originate from the back of the body of the pubic bone, some of the fibres insert to encircle the urethra, some of the fibres insert to circle the vagina, where they take part in forming the perineal body. Some of the final fibres encircle the rectum as well. Overall they form a broad U-shaped sheet.

Question 7

What are the 2 main perineal muscles? The next layer after levator ani (more superficial)

Answer 7

1) Transverse perineal muscles - superficial & deep

2) Bulbospongiosus

Question 8

What is the perineal body?

What is its role?

Answer 8

• In a central position on pelvic floor, between vagina & rectum, point where the levator ani muscles insert.
• Attached posteriorly to external anal sphincter (EAS) and the coccyx, therefore responsible for keeping anus closed.

Question 9

What is the blood supply, innervation and lymphatic drainage

Answer 9

• Blood supply from internal + external pudendal arteries, drainage through corresponding veins
• Nerve supply from branches of pudendal nerve
• Lymphatic drainage via inguinal lymph nodes

Question 10

What is a pelvic organ prolapse (POP) and its consequences?

Answer 10

• Loss of support for uterus, bladder, colon or rectum, leading to prolapse of one or more of these organs into the vagina. Common, upto 40% of women will experience it to a degree in their life.
• Has significant impacts on quality of life, with disturbances on anorectal, urinary and sexual functions.

Question 11

What is POP of the anterior compartment?

Answer 11

• Known as a cystocele or urethrocoele

- Wall between bladder and vagina weakens, causing bladder to drop or sag into the vagina

Question 12

What occurs in a middle compartment POP?

What is the name for this?

Answer 12

• Uterus prolapse or the vaginal apex/vault prolapse

- If entire uterus = procidentia

Question 13

What occurs in a posterior POP?

What is this called?

Answer 13

• The rectum may prolapse into the posterior part of the vagina - Rectocele
• Loops of bowel may prolapse into the rectovaginal space (pouch of douglas) - Enterocele

Question 14

What are the common risk factors for POP’s?

Answer 14

1) Age = due to weakening of muscles over time
2) Pregnancy
3) Vaginal delivery (4x increased risk after 1st child)
4) Obesity & causes of chronic raised intra-abdominal pressure

Question 15

What is perineal trauma and obstretric anal spinchter injuries (OASIS)?
How are these prevented during pregnancy?
What are other risk factors involved for these problems?

Answer 15

• Perineal trauma = involvement of any perineal muscle
• OASIS = involvement of the anal sphincter complex
• Epiostomy, cutting of perineal space between vagina + anus and provide some extra space + make opening of vagina wider/and encouraging mother not to push when head is crowning
• Postmenopausal oestrogen deficiency, neurological disorders (e.g.: spina bifida) & genetic tissue disorders.

Question 16

What are the symptoms & management of POP?

Answer 16

• Dragging sensation, lump, feeling of incomplete emptying of bladder
• Non-surgical = pessary ring which essentially adds extra layer of support