St A - Perineum and Urogenital Triangle Flashcards
What is the perineum?
- A component of the body wall positioned between the inferior surface of the pelvic diaphragm and skin. It is divided by a horizontal like between the ischial tuberosity into the UG triangle and anal triangle. It allows for the passage of GI, repro and urinary systems
Describe the fascia of the perineum
1) Superficial fatty layer (continuous with Camper’s fascia of the abdomen).
2) Deep membranous layer (colles’/perineal fascia) which is continuous with scarpa’s fascia
In males what are the fascia layers of the perineum continuous with?
Fatty layer fuses with membranous later of superficial fascia of penis and scrotum to become dartos fascia. It is also continuous posteriorly with ischio-anal fat pad.
Membranous layer is continuous with dartos fascia and fuses with facia lata.
In females what are the fascia layers of the perineum continuous with?
Fatty layer makes up the substance of the labia majora and is continuous posteriorly with ischio-anal fat pad.
Membranous layer is attached to posterior margin of perineal membrane and fused with fascia lata.
What is the perineal membrnae?
A layer of fibrous tissue that spans the urogenital triangle between the ischiopubic rami and attaches posteriorly to perineal body. Anterior aperture allows for passage of neurovascular bundles. The function is to provide major support for urogenital organs.
What is the urogenital triangle divided by?
The perineal membrane into a deep and superficial perineal compartment
What are the boundaries of the perineal pouches?
The superficial perineal pouch - Floor is the perineal fascia and the roof is the perineal membrane, bound laterally by ischiopubic rami.
Deep perineal pouch - floor is perineal membrane and roof is the inferior fascia of the pelvic diaphragm and inferior portion of the obturator fascia.
What structures are present in the male deep perineal pouch?
- Membranous urethra,
- External urethral sphincter,
- Bulbo-urethral glands,
- Deep transverse perineal muscles,
- Dorsal neurovascular structures of the penis,
- Anterior recess of ischio-anal fossa.
What structures are present in the female deep perineal pouch?
- Proximal part of the urethra,
- Inferior part of the external urethral sphincter muscle,
- Urethrovaginal sphincter,
- Deep transverse perineal muscle,
- Dorsal neurovascular structures of the clitoris,
- Anterior recess of ischio-anal fossa
Describe the contents of the superficial perineal pouch
- Ischiocavernosus muscle, bulbospongiosus and superficial transverse perineal muscle.
What are the contents of the deep perineal pouch
- external urethral gland, deep transverse perineal muscle muscle and the bulbourethral gland
What are the contents of the superficial perineal pouch of the male
- Root (bulb and crura) of the penis and associated muscles (ischiocavernosus and bulbospongiosus)
- Proximal (bulbous) part of the spongy urethra,
- Superficial transverse perineal muscles,
- Deep perineal branches of the internal pudendal vessels and pudendal nerves.
Describe the functions of ischiocavernosus and bulbospongiosus muscles in the males
I - Covers the crus of penis,
B - Encloses bulb of penis, compresses bulb of penis to expel last drop of urine/semen and it assists erection
Describe the contents of superficial perineal pouch in females?
- Crus of the clitoris and the ischiocavernosus muscle,
- Bulbs of the vestibule and bulbospongiosus muscle,
- Greater vestibular glands,
- Superficial transverse perineal muscles,
- Deep perineal branches of the internal pudendal vessels
Describe the function of the ischiocavernosus and bulbospongiosus muscles in the females
Ischiocavernosus - Covers the crus of clitoris and maintains the erection of the clitoris.
Bulbospongiosus - Encloses bulb and greater vestibular gland,
- Sphincter of vagina,
- Assists in erection of the clitoris,
- Compresses greater vestibular glands
