4. Clinical anatomy of the pelvic floor Flashcards
What are the functions of the pelvic floor?
- Support pelvic organs
- Continence
- Passing of urine and faeces
- Breathing
- Sexual function
- Pregnancy and Childbirth
- Maintain intraabdominal pressure
What are the 3 mechanisms of support?
Suspension, attachment, fusion
What is suspension support?
Strong vertical support working against gravity, mainly by 3 ligaments.
Which 3 ligaments are involved in suspension support?
Cardinal, uterosacral and round ligament
What is the function of the cardinal ligaments?
Attach the cervix and upper vagina to the lateral pelvic wall, at the level of the ischial spines, to hold it in place
What is the function of the uterosacral ligaments?
Attach the cervix and upper vagina to the sacrum, to hold it in place
What is the function of the Pubocervical Ligaments?
Attach the cervix to the posterior surface of the pubic symphysis. They function to support the uterus within the pelvic cavity.
What is the functions of the round ligament?
Maintain the anteverted position of the uterus
What is attachment support?
Support that comes from attachments on the pelvic
organs
What is attachment support provided by? (4)
Arcus tendinous fascia pelvis (white line), endopelvic fascia, levator ani muscles, perineal body
What is the arcus tendinous fascia and what is its function?
Thickening of the lateral parts of the pubocervical fascia (part of the ednopelvic fascia), attaches from pubic tubercle to ischial spine. Provides supportive attachment for visceral pelvic fascia, lining the urogenital organs.
What is the endopelvic fascia and what is its function?
Fascia which sits inferiorly to the pelvic peritoneum. Support urogenital organs and maintains their positions.
How does endopelvic fascia help to maintain urinary continence?
Urethra lies anterior and above it, and so gets compressed during increased intra-abdominal pressure
What is fusion support?
Support that arises from fusion of different tissues
What structures are involved in fusion support?
Involves fusion of the urogenital diaphragm and the perineal body etc.
What is the lower half of the vagina supported by?
By fusion of the vaginal endopelvic fascia with the perineal body posteriorly, levator ani muscles laterally and the urethra anteriorly.
What is the pelvic floor composed of?
Deep muscles (Levator ani), superficial muscles (perineal muscles), perineal body, urogenital diaphragm,
What are the levator ani muscles and what are their functions?
These deep muscles are a U-shaped set of muscles that act like a sling, to encircle the urethra, vagina and rectum, and provide support for these organs.
What are the different levator ani muscles?
Puborectalis, Pubococcygeus, iliococcygeus muscles
What structures do the levator ani muscles encircle?
The urethra, vagina and the rectum
What are the origins of the levator ani muscles?
Posterior surface of body of pubis, tendinous arch of levator ani and medial aspect of ischial spines
What is the tendinous arch of levator ani?
A thickening of the fascia of the obturator internus that attaches from pubis bone to ischial spine
What are the insertions of the levator ani muscles?
Some fibres insert into the perineal body as they encircle the urethra, vagina and the rectum. The rest of the fibres insert into the lower part of the coccyx
What are the perineal muscles?
Next layer after the levator ani
Transverse perineal muscles (superficial and deep), Bulbospongiosus, ischicavernosus
What is the urogenital diaphragm?
Tringular sheet of dense fibrous tissue that arises from the ischiopubic ramus which spans the anterior half of the pelvic floor. Attaches to the vagina, urethra and perineal body thereby supporting the pelvic floor
What is the perineal body and what is its function?
Occupies a central position (and role) on the pelvic
floor, between the vagina and rectum
Point of insertion of the levator ani muscles
Attached posteriorly to the external anal sphincter
(EAS) and the coccyx
Support of the perineal structures rely on it