Perineum Male and Female Flashcards
perineum boundaries
general
pubic symphisis
R and L IT’s
coccyx
diamond shape
divide in half for urogenital triangle and anal triangle
anal canal
pectinate line where endo and exoderm meet
-above line = endoderm feel stretch, pressure
-below line = exoderm, feel pain
anorectal juction in ampulla
anal sphincters
internal = involuntary
external = voluntary
external sphincter divisions
subcutaneous
superficial
deep (continuos w/ levator ani)
inn: inferior rectal N
levator ani
muscle that holds pelvic bowl contents in place
ishioanal fossa
fat filled triangle for packing levator ani in place
bound by levator ani (medial) + obturator internus (lateral) + skin (inferior)
pudendal canal
aka Alcock’s
contains pudendal nerve + internal pudendal artery + internal pudendal vein
aka nerve of shame
scrotum
testes
epididymsis
part of spermatic cord
penis -root
physically attached to body
has bulb w/ R and L crus on either side, all erectile tissue
penis - body
continuation from root
1. corpus spongiosum- from bulb, has urethra, expands to glans
2. corpora cavernosa- from R and L crura, bounded by deep penile fascia
internal urethral sphincter
distal side of bladder/proximal side of prostate aka b/t bladder and prostate
prevents retrograde ejaculation aka no semen in the bladder
anal canal arteries
collateral circulation from hindgut and internal iliac arteries
middle and inferior rectal a.s (from internal iliac) anastomose w/ superior rectal from IMA
anal canal veins
inferior mesenteric vein and superior rectal > hepatic portal
middle rectal and inferior rectal > IVC
prostatic plexus
parasympathetic nerves S2-4
somatic also
surrounds prostate
responsible for erection
superficial perineal pouch
both
- bulbospongiosus (covers bulb)
-tightens to keep blood in erect
-cleans urethra before and during ejaculation
-can weakly contract vagina - ischiocavernosus (covers crura)
-keep blood in during erection - perineal body - CT that holds entire perineum together
-shorter b/t vagina and anus for females - superficial transverse perineals- keep pelvic floor taught
all innervated by nerineal nerve from pudendal
perineal nerve
both
from pudendal
motor to:
bulbospongiosus
ischiocavernosus
levator ani
superficial and deep transverse perineal
external urethral sphincter
sensory to:
posterior skin of scrotum OR
skin of labia majora/minora
deep pouch
male
- membranous/intermediate urethra
(shortest of the 3 parts) - external urethral sphincter/sphincter urethrae @ below prostate
- bulbourethral/cowpers glands- cleans urethra of residues, duct to penile urethra
deep pouch innervation
both
dorsal nerve of penis or clitoris
sensory:
skin of penis or clitoris
responsible for sensory orgasm
sensory is the main type for females
deep pouch blood supply
from internal pudendal artery
- dorsal a. of penis to corpus spongiosum
- deep a. of penis to corpora cavernosa
need both for full erection but mainly deep A
same for female just clitoris
erection steps
- parasympathetic stimulation by cavernous nerves (S2-4) shuts down anastomoses
- smooth muscle in coiled arteries relaxes > helicine arteries straighten = cavernous sinuses fill w/ blood
- bulbospongiosus and ischiocavernosus contract = block off deep dorsal vein so sinuses can’t drain, somatic
emission steps
- semen delivered to prostatic urethra thru ejaculatory ducts and seminal vesicles, prostatic fluid added
sympathetic response aka L1-2
ejaculation steps
- internal urethral sphincter closes so no retrograde ejaculation sympathetic L1-2
- urethral muscle contracts parasymp S2-4
- bulbospongiosus muscles contract somatic S2-4
remission steps
- penis return to flacid state from sympathetic resp = constriction of smooth muscle in helicine arteries
- bulbospongiosus and ischiocavernosus relax = blood drains back into deep dorsal vein somatic
erection process
general
- erection
- emission
- ejaculation
- remission
prostate surgery
clinical correlate
damage to prostatic plexus (leads to cavernous nerves of penis aka resp for erection) so impotence
treat w/ prosthesis semirigid or inflatable NOT viagra bc problem is not arterial
UG triangle
female
aka vulva
prepuce covers clitoris
frenulum
labium majus and minus
vestibule aka vagina
clitoris
R and L crus/crura w/ erectile tissue > body > glans
bulb of vestibule of erectile tissue to maintain clitoral erection
no corpus spongiosum, bulb instead
superficial pouch
female
crus
bulb of the vestibule
paraurethral gland/lesser vestibular- prostate in men, no specific known function in female but maybe g spot?
greater vestibular gland- lubricate vaginal opening
deep pouch
female
urethra
sphincter urethrae/external
vagina
perineal membrane over deep transverse perineal muscle
females have internal sphincter but weaker than male and doesn’t usually work
dorsal nerve of clitoris
clinical correlate
cut or damanged w/
episiotomy, cancer removal, labioplasty
no orgasms
perineal body damage
uterine prolapse
childbirth- if baby head/shoulders too big then tear or destroy
why?? bc multiple muscles attachment point
uterine prolapse types
1st degree- slight descent, uterus just slips down
2nd degree- cervix at entrance of vagina
4th degree- complete prolapse, exit the body, no control over urinary bladder
prolapse treatments
- PT is best to strengthen muscles
- gellhorn pessary, only temporary, holds uterus up, can be removed to clean
- surgery to hold up uterus if no more kids
episiotomy
only done if
1. baby’s shoulder is stuck behind pelvic bone (shoulder dystocia)
2. baby has abnormal heart rate in delivery
3. operative vaginal delivery w/ forceps or vacuum
either midline or mediolateral incision
doesn’t actually prevent tearing but does heal cleaner
chronic perineal injury
males
from bicycle seats, motorcycles, horse back riding, constipation =
urinary incontinence, bowel incontinence, ED
can also be acute from trauma
pelvis and perineum SOMATICS
both-sensory
-voluntary control SOMATICS
-pudendal nerve S2-4
-external sphincters prevent leakage w/ stress, strain, sleep
-tonically active so inhibition = relax
-sensory from external anal and urethral sphincters, pelvic floor muscles, anal canal, urethra aka will let you know when bladder infection
pelvis and perineum SYMPATHETICS
both-sensory
involuntary
T11-L2
-contract internal anal sphincter and urethral for males
-contract ductus deferens, seminal vesicles, prostatic muslces during emission and remission
-poorly localized sensory but most sensitive to distension
pelvis and perineum PARASYMPATHETICS
both-sensory
-involuntary
-S2-4 (same as somatic)
-smooth muscle in organ walls
-begins erection to relax helicine arteries
-contract urethral muscle during ejaculation
-contracts detrusor/bladder and rectal muscles
-conveys normal sensation of bladder and rectal distension
