Perineum Flashcards
Boundaries of perineum
coccyx
IT
pubis
THe anal canal is divided into upper and lower halves by what?
pectinate line
Upper half of anal canal
derived from hindgut endoderm
lined by columnar epithelium
contains anal columnes
innervated by autonomics
Arteries of upper anal canal
superior rectal (off IMA) middle rectal (off internal iliac)
vein of upper anal canal
superior rectal (drains into IMV)
lymphatics of upper anal canal
travel superiorly to inferior mesenteric nodes
lower half of anal canal
dervied from extoderm of proctoderm
lined by stratifed squamous epithelium
somatic innervation
arteries of lower anal canal
inferior rectal
vein of lower anal canal
inferior rectal
lymphatics of lower anal canal
travel inferiorly to superficial inguinal nodes
Internal anal sphnicter
smooth muscle
thickening of inner circular muscular at proximal end
involuntary
external anal sphicter
skeletal muscle
coluntary
innervated by inferior rectal
ischiorectal fossa
fat filled spaces lateral to anal canal
boundaries of ischiorectal fossa
skin levator ani obturator internus sacrotuberous and sacrospinus ligaments deep transverse perineal muscles
contests of ischiorectal fossa
fat and connective tissue
pudendal canal
pudendal canal
fascial canal on lateral wall of fossa
contents of pudendal canal
pudendal nerve
internal pudenal a
internal pudenal v
pudendal n
exits pelvis via greater sciatic formane
enters perineum via lesser sciatic formation
branches of pudendal nerve
inferior rectal
dorsal nerve of penis of clitoris
perineal nerves
branches of internal pudenal a
inferior rectal
branches of penis or labia and clitoris
Superficial fascia (fatty layer) of urogenital triangle
continues with ischorectal fat
inabdomen called camper’s fascia
superficial fascia (fatty layer) of urogenital triangle in males
diminished fat in scrotum and penis
replaced by dartos muscle in skin of scrotum
superficial fascia (fatty layer) of urogenital triangle in females
makes up substances of fat in mons pubis and lavia majora
superficial fascia (membranous layer) (colles) of urogenital triangle
in abdomin called scarpa’s fascia
forms tuular sheath around penis and clitoris
superficial fascia (membranous layer) (colles) of urogenital triangle in males
attached to dartos muscle in scrotum
deep fascia of urogenital triangle
envelops muscles of peritnum
fused to suspensory ligament of penis or clitoris
in adbomen continous with fascia of external abdominal olbique and rectus sheath
continous with deep penile fascia (buck’s fasa)
male superficial perineal pouch
potential space between membranous/.colles fascia and perineal membrane
male deep perineal pouch
space between superior fascia of urogintal diagphram and perineal membrane (inferior fascia of UG diagphram)
easily ruptured
Contents of scrotum
testes
epididymis
spermatic cord
Membranous fascia (colles) attaches to and contains ______
dartos muscle
dartos muscle
elevates testes a little (mostly by cremaster)
wrinkles/expands skin of scrotum
changes surface area
innervated by genital branch of genitofemoral
in males tunic albuginea surrounds ____ and _____
corpora caverosa
corpus spongiosum
Function of deep penile fascia
binds eretile bodies togheter
root of penis
attached part of penis, located in superfical perineal puch `
erectile tissue in males
bulb
right and left crura
bulb
corpus spongioum
attached to perineal membrane
right and left crura
corpus cavernosum
attaches to ischiopubic rami
proximal spongy urethra
opens at extended urethra
Muscles that cover bulb and crura
bulbospongiosus muscles
ischiocavernosus muscles
bulbospongiosus muscles in males
paired muscles
attached via median tendinous raphe
cover bulb of penis
compress bulb when contracted
What does bulbospongiosus aid with by compressing bulb
empty spongy urethra of residual urine/semen
erection
ischiocavernosus muscles in males
paired muscles
cover right and left crura
how does ischiocavernosus muscles help with erection
compression of crura and retarding venous return
superficial transverse perineal muscles
arise from IT
insert into perineal body
fix the perineal body
perineal
small fibrous mass inc enter of perineum
What attaches at perineal
external anal sphincter
bulbospongiosus
transverse perineal muscles
Membranous urethra
smallest/narrowest part
external sphincter urethrae
muscle surround membranous urethra
voluntary
innervated by perineal branch of pudendal n
bulborectal glands
ducts extend into superficial perineal pouch to enter spongy urethra
produce a few drops that cleanse urethra and provide lubricating fluids for sexual activity
deep transverse perineal muscle
posterior to sphicter urethrae
extends from ischial rami to perineal body
dorsal nerve of penis
from pudendal n
supplies skin of penis and glands penis
branches internal pudendal a to the penis
deep a of penis
helicine branches
helicine branches
open into cavernous spaces
coiled in flaccid penis
What is inside labia
fat, smooth muscle and terminal part of round ligament
What does the labia minor form
prepuse and frenulum
vestibule
space between labia minora
What does the vestibule contain
external meati of urethra
vagina
ducts of greater and lesser vestibular glands
Root of clitoris
attached portion in superficial perineal pouch
masses of erectile tissue in root of clitoris
bulb of vestibule
2 parts of bulb of vestivule
surrounding vaginal orifice
urethral orifice
Body of clitoris
proximal detached portion of clitoris
corpora cavernosa
bulbospongiosus muscles in female
cover bulb of vestibule
compress deep dorsal vein of clit
ischiocavernosus muscles in females
cover clitoris
assist in erection of clitoris
greater vesticular glands
open into vestibule, posterolateral to vaginal opening
secreting lubricating mucus during sexual acitvity
lesser vestibular glands
corresponds to prostate
open into vestibule, lateral to urethral orfice
secrete mucus into vesticule for distribution to labia and vestibule
phimosis
foreskin can’t fully be retracted
can cause difficulity urinating and sex
pudendal nerve blood
used during childbirth and vaginal sx
internal urethral sphincter
only in males
smooth muscle at neck of bladder
prevents retrograde ejaculation into bladder
sympathetic
external urethral sphincter
striated muscle, voluntary
prevents incontinence
erection
parasymphatetic
pelic splanic nerves (S2-S4)
dilate helicine a, fill cavernous tissues w/ blood
bulbospongiosus and ischiocavernosus muscles help by compressing venous plesux
emission
sympathetic (L1-L2)
move semen to prostatic urethra
peristalisis of ductus defens and seminal vesicles
prostatic contraction adds prostatic fluid
involves glands
Glands involved in emission
seminal vesicles
prostate
bulbourethral gland
Ejaculation
somatic (also autonomic)
expulsion of secretions and spermatozoa
effected by rythmic contractions of bulbospongious and ischiocavernosus muscles
pudental (S2-4)
function of autonomics during ejaculation
parasympathetics contract urethral muscle
close internal urethral sphincter