What do we call the area of the body inferior to the pelvic diaphragm and within the pelvic outlet?
the perineum
In general, what does the perineum contain?
the external genitalia and terminal portions of the urogenital system and GI tract
What’s another term for the pelvic outlet?
the inferior pelvic aperture
What is the anterior boudnary of the pelvic outlet?
the pubic arch
What’s the posterior boundary of the pelvic outlet?
the tip of the coccyx
What are the lateral boudnaries of the pelvic outlet?
the inferior rami of the pubis and ischium and sacrotuberous ligaments
What forms the two divisions of the perineum?
an imaginary line drawn between the anteiror margin of the ischial tuberositis
What are the two divisions?
urogenital triangle - located anterior tot he transverse line
anal triangle - located posterior to the transverse line
The midpoint of the imaginary transverse line goes through the central point of the perinum which overlies what?
the perineal body, also called the central tendom of the perineum
What is the superficial perineal fascia called?
dartos fascia
What are the two layers of the superficial perineal (dartos) fascia?
the superficial fatty layer - continuous with Camper’s in the abdomen
the membranous (deep layer) and Colle’s fascia - continuous with Scarpa’s in the abdomen
What does the superficial fatty layer continue into in the female?
into the labia majora to insert near the perineal body
Describe what happens to the superficial fatty layer in males?
it’s greatly diminished in the UG triangle and cotninues around the penis into the scrotum where the fat is replaced by smooth muscle called the dartos muscle
What are the two layers of the deep perineal fascia?
the deep perineal fascia and the perineal membrane.
What are the specific layers of the deep perineal fascia?
investing layer = Gallaudet’s fascia
deep fascial layer = Buck’s fascia
Describe the perineal membrane.
it’s a thin sheet of deep fascia that is attached to the isciopubic rami laterally but doesn’t reach the pubic anteriorly
What pierces the perineal membrane in males?
the urethra
What pierces the perineal membrane in females?
urethra and vagina
What are the two spaces or pouches in the urogenital triangle?
superficial perineal space (pouch)
deep perineal space (pouch)
What layers is the superficial perineal space located between?
the membranous layer of the superficial perineal fascia (Colle’s) and the perineal membrane?
What is the deep perineal space bounded by?
by the perineal membrane - it’s open superiorly so it’s no actually an enclosed space
What are the contents of the superficial perineal pouch?
erectile bodies
superficial transverse perineal muscle
vessels and nerves of the muscles
greater vestibular glands in the female
What are the erectile bodies?
crura and bulb of the penis in males
bulb of the clitoris in females
isiocavernosus muscles covering the crura and bulbospongiosus muscle covering the bulb
What does the superficial transvers perineal muscle do?
stabilizes the perineal body
What are the vessels and nerves of the erectile body muscles branches of?
the internal pudendal artery and pudendal nerve
What’s another name for the greater vestibular gland in the female?
Bartholin’s gland
What are the contents of the deep perineal pouch?
- deep transver perineal muscle
- sphincter urethrae muscle
- compressor urethrae
- urethra
- opening for vagina in females
- bulbourethral glands in males
- internal pudendal vessels, pudendal nerves and branches
What’s anther name for the bulbourethral glands in the male?
cowper’s
What’s another name for the perineal pouch and its contents?
the urogenital diaphragm
What are the three cylindrical bodies of erectile tissue in the penis?
two corpora cavernosa found dorsally (starts at crura)
one corpus spongiosum located ventrally (starts at the bulb)
What are the three sections of the urethra in the male?
the prostatic portin (penetrates prostate)
membranbous portion (traversese deep perineal pouch surroudned by sphincter urethrae)
spongy or penile (found in the corpus spongiosum)
How does the erectile tissue of the clitorus differ from that of the penis?
clit has two crura, a body and a glans, but no corpus spongiosum because the clit isn’t traversed by the urethra like the penis is
What part of the labia minora passes posterior to the clitoris?anterior to the clitoris?
posterior = frenulum anterior = prepuce
What’s the area posterior to the clitoris - the opening of vagina, urethra and greater vestibular glands?
vestibule
What membrane partly blocks the vaginal orifice?
hymen
What are the two masses of erectile tissue that lie along the vaginal orifice covered with bulbospongiosus muscles?
the bulbs of the vestibule
What’s the wedge-shaped area on either side of the rectum loccated between the skin and the pelvic diaphragm?
the ischioanal fossae
What is the ischioanal fossae filled with?
fat - permits distention
What canal is located within the ischioanal fossae and what forms it?
the pudendal (Alcock’s) canal formed by the obturator internus fascia
lies along the lateral wall
What is contained in the pudendal canal?
easy 0 the internal pudendal artery and pudendal nerve
What branches from this neurovascular bundle go to the anal canal?
the inferior rectal artery and nerve
Besides the inferior rectal artery, what is the main branch of the internal pudendal artery?
the perineal artery and it’s various branches
What foramen does the pudendal enrve pass thorugh before crossing the ischial spine and entering the perineum?
passes through the greater sciatic foramen first
then through the lesser sciatic foramen with the internal pudendal artery into the pudendal canal
What does the inferior rectal nerve supply?
external anal sphincter
What are the two terminal branches of the pudendal nerve?
the perineal nerve and dorsal nerve of the penis
In terms of extravasation of urine…if the rupture of the urethra doesn’t penetrate BUck’s fascia, where will the urine go?
it will be confined to the penis
If the rupture of the urethra perforates Buck’s fascia, where will urine spread?
beneath Colle’s fascia (the superficial perineal fascia) in the penis, scrotum, and anterior abdominal wall, but NOT into the thigh
What is an episiotomy?
a midline relaxing incision made in the perineum to help in delivering a fetus
WHat nerve block is done for obstetric anesthesia/
pudendal nerve block
How is a pudendal nerve block done?
you can use a transvaginal or transcutaneous approach - just feel for the ischial spine to locate the pudendal nerve