Session 5a : Reproduction - Pelvic Floor & Perineum Flashcards
What are the ideal features for child birth (of the pelvis) ?
Round inlet Ischial spines not to prominent Sacral pomontry not to prominent Su- pubic arch of greater than 90º Well rounded greater sciatic notch Straight sided walls
What is measured when clinically assessing the pelvis?
Pelvic inlet - anterior posterior Diameter
Mid pelvis- bispinous diameter (distance between ischial spines) and the straight side walls
Pelvic outlet - transverse diameter of the region check between the ischial tuberosities (fist should sit here) & the infrapubic angle
How do you measure the anterior posterior diameter in females ?
You can check the different conjugates :
Anatomical : from the sacral pomontry to the superior border of the pubic symphysis
Obstetric : from the sacral pomontry to the midpoint of the pubic symphysis
Diagonal : from the sacral Pomontry to the inferior border of the pubic symphysis.
What are the features of a male pelvis?
Heart shaped inlet Narrow infapubic angle (50-60º) Medially prominent ischial spines Prominent sacral promontory Narrow and sharp ended greater sciatic notch Tip of coccyx faces more inward
What are the boundaries of the pelvic outlet?
Posteriorly : coccyx
Anteriorly : pubic symphysis
Posterolaterally : sacrotuberous ligaments
Anteriolaterally : ischiopubic rami
What are the boundaries of the pelvic inlet ?
Posteriorly : sacroiliac joints, sacral promontory
Anteriorly : pubic symphysis and the pubic crests
Laterally : arcuate line , ileopectineal line
What is the difference between the True and fake pelvis?
The pelvic inlet/ brim Seperates the pelvis into true (below it) and false (above it).
The false pelvis is a continuation of the posterior abdominal wall which contains no pelvic organs, its mainly made up of the iliac fossa.
The true pelvis is below the brim and contains the pelvic and reproductive organs.
Which two ligaments are important in the formation of the different foramen in the pelvis?
Sacrotuberous - triangle ligament the base of which is attached to the sacrum and coccyx and will run to the ischial tuberosity.
Sacrospinous - runs from the sacrum to the ischial spines.
These will help form the greater and lesser sciatic foramen.
Where are the greater and lesser sciatic notch found?
In lateral view :
The greater notch runs from the posterior inferior iliac spine to the ischial spine.
The lesser notch runs from the ischial spine to the ischial tuberosity.
Where is the perineal region located?
This is located below the pelvic outlet.
What is the perineal body?
This is a connective tissue mass located in the centre of the perineum , between the ischial tuberosities.
It is a condensation of the superficial perineal muscles, the fibres of the external anal sphincter, levator ani and the fascia of the rectum and vagina .
What are the layers of enodervical fascia which support the vagina ? And the pelvic organs ?
- The uterosacral ligament which attaches the uterus to the sacrum holding it up and in position .
- The fascia surrounding the vagina posterior and Anteriorly , this will help place the vagina laterally against the lateral pelvic wall. This means that normally the vagina is flattened laterally. This can be felt upon examination (lateral sulcus)
- The perineal region and superficial muscles
What are the key functions of the pelvic floor?
Helps stabilise the trunk - truncal stability
Aids in childbirth
Supports the pelvic viscera from rises in the interabdominal pressure
Prevents incontinence both urinary and foecal
How does the pelvic floor prevent foecal incontinence ?
The muscles of the levator ani - the puborectalis will hold the anorectal junction at a 90 degree flexure and Anteriorly , this will close the anal canal until the muscle tone relaxes and the canal can become open to defecate.
How does the pelvic floor relate to the urinary incontinence?
It will help position the urethra Anteriorly
The levator ani and the superficial muscles and ligaments will then absorb the rise in the abdominal pressure so that the bladder pressure will remain lower than external sphincter pressure, to prevent the bladder from emptying.
How does the pelvic floor aid in childbirth ?
The shape of the pelvic floor is the shape of a bowl which will push the baby’s head (rotate it) toward the urogenital hiatus.
How does the pelvic floor aid in truncal stability?
It will support the abodminal cavity inferiorly.
Note : when the abdomen contracts so does the pelvic floor.
What is an episiotomy ?
Episiotomy - is when you deliberately cut the perineum in either a midline plane (toward the anal sphincter) or in a mediolateral plane.
This is done then to limit the damage that can occur with tearing.
What is the function of the perineal body ?
Anchors the perineal muscle Anchors the vagina and the rectum Central fulcrum of pelvic support Acts as a tear resistance in the region Anchors the posterior wall of the vagina
Where is the perineum located?
Located most inferior point of the pelvic outlet
Inferior to the levator ani and above the skin of the vulva.
Which space is the perineal space continous with ?
The ischiorectal fossa
What is the ischiorectal fossa ?
This region is laterally placed to the anal canal in the deep perineal pouch, it is bordered by the obturator internus and the levator ani muscles.
It is continous with the space below the levator ani and the gluteal muscle fat, in the buttocks.
What is in the ischiorectal fossa?
Fat - this allows the distension of the anal canal
Pudendal canal - the pudenal nerve and vessels run through here.
What is the subperitoneal space in the perineum?
This is the region above the levator ani which has the uterine artery , relative lymphatics and the ureter.
What muscles make up the pelvic floor?
The lateral wall of the pelvic floor : obturator internus and piriformis (and coccygeal)
Floor : the muscles of the levator ani , puborectalis, pubococcygeus and illiococcygeus
What are the borders of the perineum ?
Diamond shaped region on the inferior side of pelvic outlet :
Posterior : coccyx Anterior : pubic symphysis Laterally : ischiooubic rami and the sacrotuberous ligaments Roof : levator ani muscles Floor : skin
How can the regions of the perineum be separated ?
They can be separated by a theoretical line drawn between the ischial tuberosities, this will separate the region into a :
Urogenital triangle Anteriorly - urethra & (vagina)
Anorectal triangle posteriorly - anus
If the urethra is pierced below the perineal membrane where is the urine collected ?
In the superficial perineal pouch
