Repro - Perineum Flashcards
Where is the perineum found?
Inf to the pelvic diaphragm, being the most inferior portion of the trunk
What structures are within the boundaries of the perineum?
- external Genitalia
- Perineal Muscles
- Anal Canal
How do we divide the peroneum up ?
Into two triangles:
- Anterior or Urogenital (Inf to Pubic symphisis)
- Posterior or Anal (Ant/inf to coccyx)
What is the peritoneal membrane?
A thin sheet of deep fascia stretching between the right and left pubic arch below the symphisis
Ext genitalia are affixed to it
Your’e looking at the perineum from underneath with the skin etc cut away. Name the 4 major perineal muscles?
Ischiocaverosus
Bulbospongiosus
Superficial & deep Transverse Perineal Muscles
Ext Anal Sphincter
What nerve innervates the perineal muscles?
Muscular branch of the perineal nerve, itself a branch of the pudendal nerve (S2-4)
Function of the Ischiocavernosus?
Stabilizes erect penis
Tenses Vagina during orgasm
Flexes Anus in both genders
Function of the Bulbospongiosus?
Erection (penile & clitoral)
Contractures of orgasm
Function of the superficial perineal muscle?
FIxes the perineal body in place
Function of the deep perineal muscle?
Fixes perineal body
Supports pelvic floor
Expels semen and last drops of urine (both genders)
What is the perineal body?
Central tendon of the perineum. Its found between the vagina/penis and anus.
The Ext Anal sphincter, Bulbospongiosus, Superficial/deep transverse perineal muscles and Ant fibres of levator ani all converge here
How is the perineal body clinically significant as part of reproduction ?
It can tear during vaginal birth which predisposes to prolapse of the uterus, rectum or bladder
How do we avoid the perineal body and surrounding tisuses tearing during birth?
Episiotomy, ideally mediolateral or lateral rather than midline
We have two pouches or potential spaces in our perineum, what are they called and what traverses them?
Superifical and Deep Perineal Pouch/space
The Urethra
What space is the ext urinery sphincter found?
Deep Perineal Space
Where is the Int Urinary SPhincter found?
In the Subperitoneal space
What muscle is found in the deep perineal space?
Deep Transverse perineal muscle
What are the widest and narrowest parts of the urethra?
Widest is the prostatic
Narrowest is the membranous (as it passes through the ext urethral sphincter)
Penile or spongy is somewhere in between
What “structure” allows the anal canal to expand when you defecate?
The Ischio-anal or Ischio-rectal fossae
Where are the ischio-anal fossae found?
Inferior to the pelvic floor and lateral to the anal canal
What is found in the ischio-anal fossae?
Adipose tissue, this along with proximity to bowel makes it vulnerable to infections
Pudendal Canal contents
What is included in the pudendal canal and how does it enter the ischio-anal canal?
Internal Pudendal Art
Internal Pudenal Vein
Pudendal Nerve
It’s the site of a pudendal nerve block and enteres the ischio-anal fossae through the Lesser Sciatic Foramen
