IX + X: Perineum I + II Flashcards
what are the boundaries of the perineum?
coccyx
2 ischial tuberosites
pubis
derivation of upper half of anal canal
hindgut
upper half anal canal lining
columnar epithelium
anal columns?
above pectinate line
vertical fold indicating anorectal junction
semilunar folds/anal valves
inferior aspect of anal columns which indicate a bumpy pectinate line
innervation to upper half of anal canal
autonomic n.
arteries to upper half of anal canal
superior rectal (IMA) and middle rectal (internal iliac)
vein of upper half of anal canal
superior rectal (to IMV —> **portal system)
lymphatics of upper half of anal canal
inferior mesenteric nodes
derivation of lower half of anal canal
ectoderm of proctodeum
lining of lower half of anal canal
stratified squamous epithelium
innervation to lower half of anal canal
inferior rectal branch of pudendal n.
lymphatics to lower half of anal canal
superficial inguinal nodes
internal anal sphincter
involuntary smooth muscle
external anal sphincter
voluntray skeletal
what innervates external anal sphincter
inferior rectal (branch of pudendal n.)
what are ischiorectal fossa?
fat filled spaces lateral to anal canal
bost deep border of ischiorectal fossa
levator ani
what is the pudendal canal?
canal withing fascia of obturator internus in the ischiorectal fossa lateral wall
3 contents of pudendal canal
- pudendal n.
- internal pudendal a.
- internal pudendal v.
is the n. to obturator internus in the pudendal canal?
enters the canal, but exits early
where do things enter the pudendal canal?
lesser sciatic foramen
what are the branches of the pudendal n. (3)
- inferior rectal
- dorsal nerve of penis/clitoris
- perineal n.
what are the branches of internal pudendal a. (2)
- inferior rectal
2. branch to penis/ labia and clitoris
which hemorrhoid would be painful above or below pectinate line?
below= painful and palpable
only autonomic nerves above
which facial layer of the perineum is fused withthe suspensory ligament of penis/clitoris?
deep fascia
what is the deep penile fascia/Buck’s fascia continuous with>
deep fascia
holds penile corpora together
space between colles fascia and perineal membrane
male superficial pouch
contents of the male superficial pouch
RIBSS roots of penis (bulb and crura) ischiocavernosus muscle bulbospongiosus muscle superficial transverse perineal m. spongy urethra
space between superior fascia of UG diaphragm and perineal membrane
male deep perineal pouch
contents of male deep pouch
IM BEDD internal pudendal a. and v. membranous urethra bulbourethral gland external urethral sphincter deep transverese perineal muscle dorsal nerve of penis
what innervates the dartos muscle
genital branch of genitofemoral
surrounds corpora cavernosa and corpus spongiosum individually
tunica albuginea of penis
binds all erectile bodies of penis together
Buck’s fascia
Bulb of penis
corpus spongiosum attached to perineal membran of UG diaphragm
Right and Left frura
corpus cavernosum attached to ischiopubic rami
which erectile body contains the urethra
corpus spongiosum
what type of erectile tissue is the glans penis (head)
corpus spongiosum
what muscles cover the bulb?
bulbospongiosus
what is the function of the bulbospongiosus
compression when contracted leads to
- emptyign spongy urethra of residual urine/semen
- erection by increasing pressure on tissue in root compressing venus return
what muscles cover the cruras?
ischiocavernosus muscles
small muscles arising from ischial tuberosity and inserting into perineal body
superficial transverse perineal muscles
perineal body
small fibrous mass in center of perineum
what structures attach to the perineal body
- external anal sphincter
- bulbospongiosus
- superficial transverse perineal muscles
muscle surrounding the membranous urethra
external sphincter urethrae
what innervates the external sphincter?
voluntary muscle innervated by perineal branch of pudendal n.
deep transverse
ischial rami to perineal body
supplies skin of penis and glans penis
dorsal nerve of the penis (from pudendal)
blood to penis
internal pudendal a.
what a. fills the corpora cavernosa with blood
deep arteries of penis
helicine branches in cavernosa
coiled in flacid penis, open into cavernous spaces
what forms the prepuce and frenulum
labia minora
space between labia minora, containing the external meati of urethra, vagina, and ducts of the greater and lesser vestibular glands
vestibule
How is the head of the clitoris different from the head of the penis
clitoris: caverosa head
penis: spongisum head
Contents of Female superficial perineal pouch
RLBIGPPIS root of clitoris lesser vestibular glands bulbospongiosus muscles ischiovaernosus muscles greater vestibular glands perineal body perineal branches of pudendal n. superficial transverse perineal muscles
Contents of Deep Female Perineal Pouch
PPISDD part of urethra part of vagina itnernal pudendal vessels sphincter urethrae deep transverse perineal muscles doresal nerves of clitoris (from pudendal )
what secretes the lubricating mucous during sexual activity?
greater vestibular glands
what corresponds to the male prostate?
lesser vestibular glands
what n. supplies clitoris
dorsal n. of the clitoris from pudendal n.
phimosis
foreskin can’t be retracted
episiotomy
cut before it tears in childbirth
erection
parasympathetic
S2-4
emission
sympathetic
L1-2
ejaculation
somatic: S2-4
and autonomic
what happens in erection
- helicine a. dilate
- bulbospongiosus and ischiocavernosus contract
what happens in emission
- movement of semen into prostatic urethra
- peristalsis of ductus deferens and seminal vesicles
- prostatic contraction
- glands involved
what happens in ejaculation
- rhythmic contractions of bulbospongiosus and ischiocavernosus
what do sympathetics do in ejacultion?
close internal urethral sphincter
what do parasympathetics do in ejaculation?
contract urethral muscle
