pelvic floor -topic 3

7/30/2019 Pelvic Floor -Topic 3

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PELVIC MUSCULATURE AND

PERINEUM


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Objectives

At the end of this topic, you should be

able to :

1. Name the muscle that make up the pelvic floor and perineum

2. Describe the muscle of the :

- Levator ani muscle- Superficial perineal muscle

- Perineum

3. State the functions of the pelvic floor muscle

4. Name the muscles that are cut when performing an episiotomy

5. Describe the changes of the pelvic floor during :-- Pregnancy

- Labour

- pueperium


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General description

Pelvic floor :

- Soft tissue

- Cover pelvic outlet- Strong sheet of muscles

- Shaped like a hammock

- Perforated by urethra, vagina and anus


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structures

Made up of 2 layers :

1. Deeper layer this is

the levator ani muscles

2. Superficial layer thisis the outer layer and

is called the superficial

perineal muscles


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Levator ani muscles

The levator ani muscles are a pair of strong

muscles about 3.5 mm in thickness. They

consist of 3 pairs of muscles namely ;

- Pubo-coccygeus

- Ilio-coccygeus

- Ischio-coccygeus


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Pubo-coccygeus

This pair of muscles arise from the pubic bone

infront, pass backwards and under the

bladder, surround the urethra and vagina in a

figure of 8 manner, pass through the perineal

body and get inserted into coccyx.


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Ischio-coccygeus

This part of muscles arise from the ischial

spines ( this sheet of muscle lie infront of the

sacro-spinous ligament) pass backwards and

get into coccyx and sacrum


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Summarise

Pelvic floor 2 layers

Deeper layer is levator ani

Superficial layer is superficial perineal muscles Pubo-coccygeus from pubic bone to coccyx

Ilio-coccygeus from the ilium to the coccyx

also Ischio-coccygeus from ischial spines to coccyx

and sacrum


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Assessment

What is pelvic floor?

Name the 3 structures that perforate the

pelvic floor.?

Name the 2 layers of muscles that make up

the pelvic floor


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Superficial perineal muscles

This muscle lies below the levator ani muscle.

They consist of 4 small pairs of muscles. The

muscles are :

a. External sphincter of the naus

b. Transverse perineal muscles

c. Bulbo-carvenosus

d. Ischio-carvenosus


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Superficial perineal muscles


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Description

External sphinter of the anus

- This muscle surrounds the anus. Some longer

fibres get inserted into the perineal body and

some get attached to the coccyx

- Function of this muscles : assist in the act of

defaecation


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Cont,

Transverse perineal muscles

- They arise from both sides of the ischialtuberosities and meet at the centre of the

perineal body Bulbo carvenosus

- These muscle arise from the centre points of

the perineum, surround the vagina and passupwards and get inserted into the corporacarvenosa ( body of clitoris )


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Cont,

Ischio-carvenosus

- The muscles arise from the ischial tuberosities

and they pass upwards along the inferior ramii

and get inserted into the corpora carvenosa of

the clitoris.

- The triangular ligament fills the triangular

space left behind.


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Functions of the pelvic floor

Covers the pelvic outlet

Supports the pelvic organs like the uterus,

vagina, bladder and rectum

Assists in the control of the intra-pelvic

pressure during coughing, laughing and

starining

Assists in the act of defaecation and birth of

the baby


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Cont,

Blood supply

- Comes from the pudendal arteries

Venous return- Venous blood returns to the heart via the

pudendal veins

Lymphatic drainage- The lymph drains into the inguinal and external

iliac glands.


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The perineal body

It is a fibre-muscular structure situated

between the lowest third of the vagina

infront, the anal canal behind and the ischial

tuberosity laterally

Shape triangular

Size 4 cm x 4 cm

Function assist the head to rotate forward

during the birth process


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Muscle of the perineal body

Pubo-coccygeus

Bulbo-carenosus

Transverse perineal muscles External sphincter of the anus


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Cont,

Blood supply to perineal body

- Comes from the pudendal arteries

Venous return

- Returns to the heart via the pudendal veins

Nerve supply

- Pudendal nerves


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Pelvic floor changes

Pregnancy

- The muscle are softerned by the action of hormonerelaxine and it allows the uterus to sink down thuscreating a situation called lightening.

Labour

- In the 2nd stage as the baby descends, the pelvic floormuscle parts like a swing whereby the muscles aredisplaced upwards, backwards and laterally

- The perineal body stretches to its full capacity as themothers bears down to push out the babys head


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Cont,

Pueperium

- At the end of labour the pelvic floor becomes laxedbecause it has been stretched during labour andremains so up to the 3rd week of pueperium. It takes

6/52 for the muscle to regain back its tone.- By the end of the pueperium the muscles have

regained back its tone but it will not return it to its pre-gravid tone.

- Infection of the perineal wound may result in weakness

of the muscles or scar tissue formation, weakness of

the muscles may result in prolapse of pelvic organs


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Complications that can occur to the

pelvic floor

1. Labour

a) Loss of muscle tone

cause :

the mother bears down prematurely or toolong resulting in overstreching

of the muscles.

b) Tears of varying degrees1 st degree tear ( 1 tear )

( skin of the fourchetted is torn )


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2 nd degree tear ( 2 )

( fourchette , perineal skin, perineal muscles,vaginal

mucosa and the external anal sphincter are torn )

3 rd degree tear ( 3 )( the fourchette, perineal skin,perineal muscles,

vaginal mucosa and the external anal urethral area

resulting in profuse bleeding )

c) Lacerations big or small around the clitoris and urethralarea resulting in profuse bleeding


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Causes of perineal tears

Rapid and sudden expulsion of the babys head

Persistent occipito posterior position in which alarger diameter stretches the vagina

Big babies Difficult forceps delivery

Misapplied perineal support

Poor technique in the delivery of the baby Rapid perineum

Old scar tissue gave way


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Prevention of tears and other injuries

1. Seek medical aid if labour is prolonged

2. Practise correct technique in the delivery of the baby by

a) maintaining flexion on the head during crowning toprevent rapid expulsion of the babys head

b) Instruct mother to pant when the head is crowned andallow the contraction to slowly expel the head

3. Do a timely episiotomy to enlarge the vaginal

orifice

4. Wait till shoulders are in the antero-posterior diameter of

outlet before delivering the shoulders. Deliver the anterior

shoulder first then the posterior shoulder.


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Effects of injuries to the pelvic floor

1. Loss of muscle tone if the lacerated muscle

are not repaired

2. Infection will set in

3. Prolapse of pelvic organs due to weakness of

the pelvic floor muscles


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Changes during pueperium

The falling level of progesterone allows themuscles to regain back its tone

This process of recovery is gradual. It is also

aided by early ambulation, post partumexercises and avoidance of constipation

If there is edema in the tissues of the

perineum after the birth of the baby, theexcess fluid will be reabsorbed by the third orfourth day of puerperium

pelvic floor -topic 3

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