LEC34: Pelvis, Perineum, and Female Reproductive Anatomy Flashcards
openings in male pelvic diaphragm
urethral hiatus, anorectal hiatus
openings in female pelvic diaphragm
urethra, vagina, rectum
muscles of pelvic diaphragm
puborectalis, pubococcygeus, iliococcygeus, coccygeus (ischiococcygeus)
extremity muscles
muscles that move the lower extremity, but origins are outside pelvic diaphragm
obturator internus, piriformis
levator anai
muscles that elevate the anus; cover pelvic opening
puborectalis, pubococcygeus, iliococcygeus
clinical significance of women having wider gap between levator anai muscles
after birth, area becomes loose, more likely to have organs prolapse through this area
kegel
exercises women can do to tighten pelvic floor muscles
what does pelvic diaphragm support
organs: rectum, bladder, uterus
where is external anal sphincter
below pelvic diaphragm
muscles of anal sphincter
1) levator ani portion of pelvic diaphragm (SKELETAL)
2) external anal sphincter (SKELETAL)
3) internal anal sphincter (SMOOTH)
what innervates anal sphincter area
inferior rectal nerve, branch of pudendal n.
S2, 3, 4
what is the shape of the anal canal / why does this matter
banana shape- flexure from sigmoid colon > rectum
anything inserted into canal must be flexible, not too big for that area (i.e. re: abuse)
2 triangles inferior to pelvic bones
anal triangle of perineum, urogenital triangle of perineum
boundaries of anal triangle of perineum
point of coccyx, front of pubis, ischeal tuberosities (on side)
what structure is wider in females
urogenital triangle of perineum - can widen during childbirth
perineum meaning
“area around the newborn”
same name for men and women
what surrounds anal triangle
ischiorectal fossa, pocket filled with fat - can compress when vagina or anus expands, and is expendable
urogenital diaphragm (UGD)
aka deep perineal pouch
forms a shelf superficial to the pelvic diaphragm, has 2 layers of fascia
layers of fascia around UGD
superior and inferior (perineal) fascia layers
what does UGD’s fascia membrane contain
contains muscles of urogenital diaphragm in a pouch called deep perineal pouch
what is within deep perineal pouch
deep transverse perineal muscle
sphincter urethrae m (males)
sphincter urethrea m + spincter urethrovaginalis (females)
structures within male urogenital diaphragm/deep pouch
urethral sphincter, bulbourethral gland, deep transverse perineal muscle
what does bulbourethral gland contribute to
fluid of the ejaculate
shape of female bladder
flat top, except when very expanded, because uterus sits directly on top
urethra length in women vs. men
short in women, long in men
is cistitis more common in women or men
women because their urethra is so short, can get bacteria up tube very easily
cell type of bladder, importance
transitional epithelium
allows for massive distortion of shape of whole organ
why does bladder sometimes appear to be an abdominal organ, and is it?
transitional epithelium of bladder means bladder can change shape, go over pelvic brim, appear to go into abdominal area, although in reality it’s in peritoneum so isn’t an abdominal organ
can you work out your bladder muscles
no!
can train yourself to not react when full, but not skeletal, so not excercisable
can you work out pelvic floor muscles?
yes!
are skeletal muscles, so can work them out
sections of male urethra
1) preprostatic part
2) prostatic part- through the prostate
3) membranous part- through peritoneal membrane
4) spongy part- through penis
where do prostate fluids drain
prostatic sinuses, where prostatic utricle, opening of ejaculatory ducts are
sympathetic innervation of pelvic area
superior hypogastric plexus
comes from above
parasympathetic innervation of pelvic area
pelvics
go into inferior hypogastric plexus
> smooth muscle of pelvis, i.e. bladder, to propel things down the ureter
what controls erectile tissue
blood flow
controlled by autonomics of pelvic splanchnic nerves
prostatic plexus
cluster of nerves from inferior hypogastric plexus nerves; run on both sides of diaphragm, cluster around prostate
makes surgery difficult
glans
where fluid exits seminal vesicle
common ducts for urination and ejaculation
ejaculatory duct, prostatic urethra, membranous urethra, spongy (penile) urethra
erectile tissue made of
corpus cavernosum, corpus spongiosum
which erectile tissue is where urethra runs
corpus spongiosum
why isn’t the clitoris a male penis
the urethra doesn’t pass through it
its erectile tissues do not enclose the urethra
what structures do sperm pass through
testis, epididymis, prostate, passage through diaphragms, corpus spongiosum, glans
what surrounds corpus cavernosum
tough fibrous coat
ensures tissue is extremely stiff when erect, penetration occurs
why is it important corpus spongiosum is spongy
stays soft, even when erect, so can expand and allow ejaculate w/ sperm to travel through
os penis
most mammals have penis made of bone; humans likely don’t because ability to become erect means good cardiovascular strength; evolutionarily helpful for mate-finding
female erectile tissue function
stiffens the vaginal orifice
female erectile bodies/locations
1) corpus cavernosum (body, glans, crus of clitoris)
2) corpus spongiosum (bulb of vestibule)
greater vestibular glands function
lubricate vagina
what stiffens vaginal orifice? bulb of vestibule function
bulb of vestibule
clitoris body and glans homologous to
dorsal paired penis bodies
bulbs of vestibule homologous to
bulb of penis, ventral body, glans
where are erectile tissues located
superficial to UGD, in superficial pouch/perineal space
what covers erectile tissues
skeletal muscles
what covers crus of clitoris
ischiocavernous muscles
what covers spongy tissue, bulb of penis?
bulbospongiosus musle
skeletal muscles of superficial pouch
bulbospongiosus, ischiocavernosus, superficial transverse perineal
what does superficial pouch contain?
scrotal contents, erectile tissues, skeletal muscle covers, an outer layer of fascia
superficial pouch location re: UGD
below
is urethra inside the clitoris?
no! separate. women do not pee out of their vagina.
homologue to testis
ovaries
homologue to gubenaculum
round ligament
homologue to prostate
skene’s glands
homologue to prostatic utricle
uterus
homologue to bulbourethral glands
greater vestibular glands
skene’s glands
aka female prostate
located between urethra and vagina
has ducts, glands; make fluid, “female ejaculation,” serves antimicrobial purpose to prevent intercourse-induced cystitis
what is g-spot, why controversial
region of anterior vaginal wall
proposed to have increased sensitivity, but no anatomical data exists to support this
homologue to body of penis
shaft of clitoris
homologue to skin around scrotum
labium majus
homologue to raphe of penis
urethral opening
innervation of female external genitalia
perineal branch of pudendal nerve, inferior rectal nerve (around anus)
blood supply to external female genitalia
perineal branches of internal pudendal artery, inferior rectal artery (around anus)
bladder innervation
smooth m., so GVE fibers from lumbar splanchnics (sympathetic) and pelvic splanchnics (parasympathetic)
pelvic, UGD diaphragms, superficial pouch innervation
skeletal m., so GSE fibers from pudendal & other sacral spinal nerves (S2-4)
ovary innervation
GVA fibers; travel along ovarian artery to T10
uterus, vagina innervation
GVE fibers from lumbar splanchnics (sympathetics), pelvic splanchnics (parasympathetics); GVA back travel along same path
lymphatic drainage from ovaries goes where?
aortic lymph nodes
where do ovarian (gonadal) arteries branch from?
directly from abdominal aorta
which arteries are crucial to pregnancy?
abdominal aorta branch:ovarian a.,
internal iliac branches: uterine a., vaginal a., internal pudendal a.
all anastomose, support pregnancy
size of uterus over lifetime
grows from birth > puberty > adult > menopause, regresses to size of before changes happened during puberty
uterus position re: bladder?
uterus is in an anteverted position over bladder
what facilitates vaginal walls’ stretch?
abundance of fat in anterior recess of ischiorectal fossa
cardinal ligaments function, location
aka lateral cervical ligament/suspensory ligament
at base of broad ligament of the uterus
contains uterine artery, vein
attaches cervix to lateral pelvic wall by attachment to obturator fascia of obturator internus m.
ligaments that support uterus, ovaries
round ligament (ligamentum teres), proper ovarian ligament, uterosacral fold, suspensory ligament of ovary (contains ovarian vessels)
layers of broad ligament of uterus
covers uterus
1) mesometrium- around body of uterus
2) mesoalpinx- around tube
3) mesovarium- comes out toward us, where ovary is suspended
what surrounds cervix
fornix; have 2 fornices (anterior, posterior)
back alley abortion with straight tool can penetrate posterior fornix, go into peritoneum
what is cervical opening called
os
what/where is opening of uterine tube?
os of uterine tube
in middle of fimbriae
how do you ensure a woman can be fertilized, tubes aren’t closed?
introduce dye into uterus, it emerges from ostia of uterine tubes and enters peritoneum
what happens during ovulation that causes pain?
parietal peritoneum tears > pain
why can uterus expand for pregnancy?
transitional epithelium, smooth muscle
where does a pregnant woman feel late appendicitis pain?
anywhere that her appendix has been pushed
why do pregnant women need to pee so much and become constipated?
bladder becomes compressed, above public arch; rectum compressed also
why so much pain during childbirth?
so many different nerve fibers in this area carry pain from all different surrounding structures
epidural anesthesia mitigates pain
