Pelvic floor, perineum and tears

Question 1

What is the pelvic floor?

Answer 1

Base of the pelvis

Formed by the soft tissues that fill the outlet of the pelvis

Question 2

Can you describe the pelvic floor?

Answer 2

Funnel shaped

Question 3

What are the two muscle layers of the pelvic floor?

Answer 3

Superficial and deep layers of the levator ani

Question 4

What is the levator ani?

Answer 4

The pubococcygeus, the puborectalis, and the iliococcygeus
They fix the pelvic structures and give support against increased abdominal pressure dduring lifting, coughing, defecation, urination and coitus.
The ischiococcygeus and levatores ani combined form the pelvic diaphragm

Question 5

What are the deep muscle layers?

Answer 5

Ischiocavernosus- passes from ischial tuberosisties (sit down bones- bottom of ischium), along pubic arch to corpora cavernosa of clitoris

The body of clitoris consists of two corpora cavernosa covered by their ischiocavernosus muscles

Bulbocavernosus- like a bulb from perineum, around vagina to clitoris- which is just behind symphysis pubis/pubic arch

External anal sphincter - surrounds anus, attached by muscle fibres to coccyx

Transverse perineal muscles- extends from ischial tuberosities to the centre of the perinem

Membranous sphincter of urethra- the membranous sphincter of the urethra is com- posed of muscle fibres passing above and below the urethra and attached to the pubic bones. It is not a true sphincter since it is not circular, but it acts to close the urethra

Question 6

What are the superficial muscle layers?

Answer 6

Pubococcygeus from posterior inferior pubic rami to pubococcygeus passes around the rectum and continues to its insertion on the coccyx and the lower sacrum

Puborectalis from posterior inferior pubic rami and continue as fibres pass posteriorly encircling the rectum becoming part of the anorectal ring

Iliococcygeus- converges with the pubococcygeus where it inserts into the coccyx and lower sacrum. The iliococcygeus forms a hori- zontal sheet that spans the opening in the posterior region of the pelvis providing a ‘shelf’ for the pelvic organs to rest on

Ischiococcygeus originates from the ischial spine and adjacent sacroiliac fascia. It attaches to the coccyx, the lower sacrum and the median portion of the sacrotuberous ligament.

Question 7

What is the function of the pelvic floor?

Answer 7

j

Question 8

What is the perineum?

Answer 8

Area between the anus and the scrotum or the vulva

Question 9

What is the pelvic fascia?

Answer 9

Between the muscle layers, and also above and below them are layers of pelvic fascia.
Loose areolar tissue is used like packing material in the spaces

Question 10

What is the triangular ligament?

Answer 10

The tissue that fills the triangular space between the bulbocavernosus, the ischiocavernosus and the trans- verse perineal muscles

Question 11

What are the functions of the internal and external anal sphincter?

Answer 11

The combined action of the internal anal sphincter and the external anal sphincter retains fecal matter in the rectum. The ability to do this is called continence.

Involuntary parasympathetic nerves traveling over the pelvic nerve control the tone of the internal anal sphincter.
The internal anal sphincter is a circular smooth muscle layer under involuntary control and is mainly contracted in rest

Question 12

What is the blood supply to the perineal muscles?

Answer 12

The internal pudendal artery

Question 13

Which ligaments support the pelvic floor and anorectum?

Answer 13

g

Question 14

Which nerves supply the pelvic floor and surrounding structures? How may these become damaged during labour?

Answer 14

g

Question 15

Which muscles constitute the perineal body?

Answer 15

g

Question 16

What is the function of the perineal body? Why is this area so important in practice

Answer 16

f

Question 17

Why is there an increase in 3rd and 4th degree tears?

Answer 17

Rise in maternal age at first birth (thought that perhaps as you age, collagen decreases and so perineum can’t stretch as well but young women are still having OASIS)
Increase in maternal weight
Better case detection
Improved recording of OASIS (obstetric anal sphincter injuries)
Increased awareness and training
Over diagnosis
Changes in management of second stage

Question 18

Extra information from lecture

Answer 18

Combination of internal and external sphincter allows flatulence without excreting

4x more likely to have urinary incontinence if you have faecal incontinence as everything in the pelvis lie so close together and some nerves serve both the urethra and the anal sphincters
3a- less than 50% of external anal sphincter
3b- more than50% of internal anal sphincter
3c- through to internal anal sphincter
4- all the way through to the anal mucosa

Anal sphincter enlarges at time of crowning and there’s more lateral stretch than AP stretch therefore 60 degree episiotomy at crowning to avoid anal sphincter

You must do a PRexamination to assess degree of tear
Position- can determine degree of tear
Good positions- flatback all fours, left and right lateral, semi-recumbent
Bad positions- squatting positions (too much gravity-only really needed for descent + can’t get hands there), lithotomy (increased risk of 3rd/4th degree tear)
Extra pair of hands at birth
Assess perineum troughout
Communication- the amount of info you give must be proportional to the amount of risk
Hands on technique
Episiotomy (if required)
S-L-O-W-L-Y

Increased risk of tear in pool as MW can’t see and can’t put hands son - good for pain relief but for delivery probably better off outsde the pool

SOuthern Asian iat increased risk of 3rd/4th degree - shorter perineum, partucularly Sri Lankan
Perineum goes wite an dshiny when perineum is overstretched and can’t go anymore as blood vessels are compressed therefore blood supply is cut off

Assessment- does perineum look healthy?
put finger to assess at entroitus to assess how much stretch left but don’t run fingers along continuously

Episitomy should be 4cm long otherwise still risk of 3rd degree tear
Encourage mum to refrain from pushing and breathe baby out slowly
Wait for restitution to occur (still supporting perineum) + encourage mum to push gently to deliver shoulders

Don’t use downward traction excessively

Question 19

What is the follow up care?

Answer 19

Follow up care
Dedicated clinic fortnightly 
Seen at 16 weeks postnatal
physiotherapy 
Consistent care and advice 
Correct medication (no fybogel- bulks up stool) and titrate lactulose (only take as needed so not incontinent)