Lecture 5- The pelvic floor Flashcards
what resides within the pelvic cavity
The pelvic viscera (bladder, rectum, pelvic genital organs and terminal part of the urethra)
gross structure of the pelvic floor- which muscles make ip the lateral walls?
obturator internus and piriformis
The pelvic floor is a …………..structure.
funnel-shaped
where does the pelvic floor attach to and what does it separated
It attaches to the walls of the lesser pelvis, separating the pelvic cavity from the perineum inferiorly (region which includes the genitalia and anus).
In order to allow for urination and defecation, there are a few gaps in the pelvic floor. There are two ‘holes’ that have significance:
Urogenital hiatus
Rectal hiatus
Urogenital hiatus –
an anteriorly situated gap, which allows passage of the urethra (and the vagina in females).
Rectal hiatus –
a centrally positioned gap, which allows passage of the anal canal.
Between the urogenital hiatus and the anal canal lies a fibrous node known as the ………………, which joins the pelvic floor to the perineum
perineal body
functions of the pelvic floor
- Support of abdominopelvic viscera (bladder, intestines, uterus etc.) through their tonic contraction.
- Resistance to increases in intra-pelvic/abdominal pressure during activities such as coughing or lifting heavy objects.
- Urinary and faecal continence/defaecation/ micturition. The muscle fibres have a sphincter action on the rectum and urethra. They relax to allow urination and defecation.
- Faciliatate child birth
3 main components of the pelvic floor (muscles)
Levator ani muscles (largest component).
Coccygeus muscle.
Fascia coverings of the muscles.
Levator Ani Muscles- Innervated by
the anterior ramus of S4 and branches of the pudendal nerve (roots S2, S3 and S4).
what sort of muscles are the leavtor ani muscles
broad sheet of muscle
Levator Ani Muscles composed of
three spearate paired muscles
- pubococcygeys
- puborectalis
- iliococcygeus
Levator Ani Muscles attachments : anteior
pubic bodies of the pelvic bones
Levator Ani Muscles attachments: laterally
thickened fascia of the obturator internus muscle, known as the tendinous arch.
levator ani muscle attachments: posteriorly
the puborectalis muscle is a
U-shaped sling
where does the puborectalis muscle extend
from the bodies of the pubic bones, past the urogenital hiatus, around the anal canal.
tonic contraction of the puborectalis
bends the canal anteriorly, creating the anorectal angle (90 degrees) at the anorectal junction(where the rectum meets the anus).
if tonic cotnraction bends the canal anteriorly (creating an anorectal angle of 90 degrees) what is the main function of the puborectalis
The main function of this thick muscle is to maintain faecal continence – during defecation this muscle relaxes.
puborectalis also includes
pre-rectal fibres
Some fibers of the puborectalis muscle (pre-rectal fibers) form another U-shaped sling that flank the urethra in the male and the urethra and vagina in the female (in some textbooks they appear as pubovaginalis or sphincter urethrae / vaginae).
pre-rectal firbes of the puborectalis are important in
These fibers are very important in preserving urinary continence, especially during abrupt increase of the intra-abdominal pressure i.e. during sneezing.
Pubococcygeus
The muscle fibres of the pubococcygeus are the main constituent of the levator ani.
where does rhe pubococcygeus muscle arise from
arise from the body of the pubic bone and the anterior aspect of the tendinous arch.
The fibres travel around the margin of the urogenital hiatus and run posteromedially, attaching at the coccyx and anococcygeal ligament.
iliococygeus muscle fibres
thin muscle fibres,
Iliococcygeus muscles fibres arise from
which start anteriorly at the ischial spines and posterior aspect of the tendinous arch. They attach posteriorly to the coccyx and the anococcygeal ligament.
which levator ani muscle is the actual “levator” of the three
illiococcygeus: : its action elevates the pelvic floor and the anorectal canal.
Coccygeus muscle innervated by
Innervated by the anterior rami of S4 and S5.
The coccygeus compared to levator ani muscles
is the smaller, and most posterior pelvic floor component – as the levator ani muscles are situated anteriorly.
coccygeus oriignates from the
ischial spine and travels to the lateral aspect of the sacrum and coccyx, along the sacrospinous ligament
(saggital cut throguh the pelvic, showing lateral view of the pelvic floor and muscles)
Pelvic Floor Dysfunctions (2)
- incontinence
- prolapse
- Posterior compartment pelvic floor dysfunction
- Obstetric trauma inc episiotomy (cut made to the pelvic floor to help baby be delivered)
- Female genital mutilation
- Vaginismus
- Vulval pain syndrome
role of leavtor ani muscles during preganancy
levator ani muscles are involved in supporting the foetal head during cervix dilation in childbirth
During the second phase of childbirth, the levator ani muscles and/or the pudendal nerve are at
high risk of damage.
Label this diagram
A- pubococcygeus
B- puborectalis
C- coccygeus
D- illiococcygeus muscle
saggital view of the pelvic floor
looks like a hammock
looking at pelvic floor muscles from aove
Bone and Levator ani muscles (power stance)
- Iliococcygeus m.
- From illium to the coccyx
- Pubococcygeus m.
- From pubis to coccyx
- Puborectalis m.
looking at the pelvic floor from below
- Orifices maintained
- Rectum
- Urethra
- Vagina
the perineal body
everything attaches to it
- Occupies a centra position (and role) on the pelvic floor, between the vagina and rectum
- Point of insertion of the levator ani muscles
- Attaches posteriorly to the external anal sphincter (EAS) and the coccyx
- Support of the perineal structures rely on it
perineal muscles of note
- Transverse perineal muscles
- Superficial
- Deep
- Bulbospongiosus
2 diagrams which summarise pelvic floor musculature
- Stars= levator ani
- Arrow- transverse perineal muscle (deep and superficial)
- In the centre- perineal body
Anterior compartment prolapse
- The bladder prolapses- cystocele
- The urethra prolapses- urethrocoele
- Cystourethrocoele- prolapse of both bladder and urethra
posterior compartment pOP
sterior compartment
- Rectum may prolapse into the posterior part of the vagina- rectocele
- Loops of bowel may prolapse into the rectovaginal space (pouch of douglas)- enterocele
Middle compartment
- In middle part or vaginal apex, the uterus may prolapse= uterine prolapse
- If entire uterus= procidentia
- Following hysterectomy, apex may still prolapse= post hysterectomy vault prolapse
prevention of Obstetric Anal sphincter injuries (OASIS)
- Episiotomy (for at risk groups and correct angle) i.e. restrictive use
- For every 6 degree the episiotomy is made away from the midline, there is a 50% reduction in third-degree tears
- Perineal protection at crowning can be protective
- Encouraging mothers not to push when the head is crowning
the vulva
Vaginismus-
pain on vaginal penetration due to involuntary muscle spasm
Female genital mutilation (FGM)
*
All procedures involving partial or total removal of the external female genitalia or other injury to the female genital organs, whether for cultural or other non-therapeutic reasons
causes of posteiror compartment pelvic floor dysfunction
- Structural e.g. rectocele, rectal prolapse
- Drugs e.g. opiates, iron supplements
- Dehydration
- Immobility
- Pregnancy
- Postoperative pain
Anal/ faecal incontinence
- Involuntary loss of flatus, liquid or solid stools that is a social or hygienic problem
- Causes both physical and psychological distress- leads to signif impairment of QoL
- Commonest cause of faecal incontinence in women= obstetric and sphincter injury
