Extra Pelvis/perineum cards Flashcards
Levator ani complex- O, I, In
O- (laterally/peripherally) attaches to pubic bone body, tendinous arch of obturator internus + ischial spine
I- (centrally) vag wall/prostate, perineal body, rectum/anus junction + anococcygeal ligament
In- levator ani (S4) + inferior anal nerve
obturator internus- O, I, Axn, In
O- pubis/ischium + obturator membrane (exits LSF) I-greater trochanter Axn- lateral rotator of thigh In- nerve to obturator internus (L5-S2)
Coccygeus- O, I, Axn, In
O- anterior sacrum + coccyx
I-ischial spine
Axn-supports pelvic viscera, flexes coccyx
In-ventral rami S4 + S5
piriformis- O, I, Axn, In
O- anterior sacrum (exits GSF) I-greater trochanter Axn- lateral rotator of thigh In- ventral rami S1 +S2
which muscles attach to the anterior sacrum?
coccygeus and piriformis
which two muscles are lateral rotators of the thigh?
piriformis and obterator internus
what is the narrowest FIXED diameter of the pelvis?
AP diameter, obstetric/true conujate
what is the narrowest non-fixed diameter of the pelvis
interspinous distance (between ischial spines)
how is the obstetric/true diameter estimated?
take the diagonal conjugate (BOTTOM of pubic symphysis to the sacral promontory) and subtract 1cm
where is the endopelvic fascia?
fills potential spaces - prevesical + retrorectal, paravesicular and retrouterine.
Denser condensations of it form ligaments
where is the hypogastric sheath? what does it allow passage of?
separates pre/para vesical spaces and retrorectal spaces
-passage of structures (neurovasc, ureters, vas defrens) from lateral pelvic wall to viscera?
what makes up the pelvic floor/diaphragm? (medial to lateral)
levator ani- puborectalis, pubococcygeus, ileococcygeus
extends to membrane obterator internus laterally) coccygeus (most posterior
borders of the pelvic wall: anterior
what does it support?
pubic symphysis, bodies and rami.
-supports weight of bladder
borders of pelvic wall: lateral
body of ilium + ischium obterator foramen (covered by membrane of Ob internus)
borders of pelvic wall: posterior
sacrum and coccyx, sacrospinous + sacrotuberous ligaments, piriformis
what are the only truly intraperitoneal elements of the pelvis?
uterine tubes (with ovary)
what does the pelvic inlet (superior pelvic aperature) divide?
greater and lesser pelvis
landmarks of pelvic inlet (superior pelvic aperature)
all defined by pelvic brim: sacral promontory
linea terminalis: arcuate line, pectin pubis, pubic crest
what is the other name for the superior pelvic aperature? where are the anterior and posterior landmarks?
pelvic inlet: diagonal line..
anterior- upper pubi symphysis
posterior: sacral promontory
what is the other name for the inferior pelvic aperature? what are the anterior and posterior landmarks?
pelvic outlet: horizontal line
anterior- pubic arch (under pubic symphysis)
posterior- coccyx
what does the pelvic outlet/inferior pelvic aperature divide?
lesser pelvis and perineum
landmarks of the borders of the pelvic outlet/inferior pelvic aperature?
pubic arch of ischiopubic rami
ischial tuberosities
sacrotuberous ligaments
tip of coccyx
where are the pubic tubercles?
anterior surface on either side of pubic symphysis
-bumps pushing out from just along/under pubic crest
where does the common iliac “bifurcate”?
what does the internal iliac descend toward?
where is the ureter in relation to this?
L5-S1
- internal iliac descends toward GSF
- ureter crosses anterior to bifurcation
what vertebral level is the rectosigmoid jxn?
what is the anatomical change here that shows this change?
S3
- convergence of tenia coli (to form continuous longitudinal muscle)
- absence of epilpoic appendages
what is the rectum supported by in the lesser pelvis?
laterally- lateral rectal ligament
what are the two main groups of the 5 flexures of the rectum?
2 anteroposterior
3 lateral
what are the 2 anteroposterior flexures of the rectum?
sacral (sacrum/coccyx contour)
anorectal (@ pelvic diaphragm) - 80 degrees formed by puborectalis muscle
what are the 3 lateral flexures of the rectum?
“transverse folds/ valves of houston”
superior (left)
intermediate (right)
inferior (left)
where is the rectal ampulla located between?
inferior flexure/ valve of houston and pelvic diaphragm
what kind of tissue is the labia majora composed of?
subQ fat and smooth muscle
where are the bulbs of the vestibule located?
deep to labia minora
what enters alcock’s canal and where is this located?
aka pudendal canal
- pudendal nerve
- internal pudendal artery + vein
- descend behind sacrospinous ligament and enter canal just inferior to it
- nerve to obt. internus (L4-S1) is somewhat included in this
what neurovasculature leaves alcock’s canal first (most posterior end) and what does it go on to supply?
most posterior (first to leave) - inferior rectal artery and nerve --> go to supply anal canal and perianal skin
what leaves alcock’s canal at the bottom (anterior) end? what does it go on to supply
first:
perineal artery–> posterior scrotal/labial
perineal nerve
–> deep branches- motor to perineal muscle (ischiocavernosus + bulbospongiosus)
–>superficial- sensory to posterior scrotal/labial skin
second:
dorsal penis/clit arteries –> superficial tissues, C. spongiosum
deep arteries –>erectile tissues -C. cavernosum
Dorsal nerve –> sensory to glans
what does the post-anal space function? what does it contain?
-allows communication between ischioana fossae
-Supports anal canal, allows expansion
filled with ischioanal fat
contains inferior rectal vessels & nerve
where is the anus located? where does it start and end? anterior/posterior boundaries?
Extends from pelvic diaphragm to anus
Between perineal body-anterior & anococcygeal ligament-posterior
what is the difference in muscle type of the internal vs external anal sphincters?
internal- circular smooth muscle
external- skeletal
venous drainage above and below pectinate line?
above- portal venous system
below- IVC
what muscle helps empty residual semen/urine?
bulbospongiosus
what forms the external raphe (and two compartments) ?
dartos muscle
what is the clitoris composed of?
two crura- corpus cavernosum - glans has spongiusum (arguable?…)
where is the corpus spongiosum of the female?
two bulbs of vestibule (none in clitoris)
what is the “sphincter” muscle of the vagina? what is its other function?
bulbospongiosus muscle, compresses greater vestibular glands to secrete mucus into vagina
external anal sphincter, what does the deep portion blend with? what is the innervation of the external anal sphincter?
Deep portion blends with puborectalis
Innervated by inferior rectal nerve
where on the sacrum to sacrospinous and sacrotuberous ligaments attatch
both: lateral sacrum
limits of the pelvic cavity: inferior? deepest ?
Inferior limit is pelvic diaphragm, deepest centrally at pelvic outlet
which parts of the levator ani complex merge at the acoccocygeal ligament?
only pubococcygeus and iliococcygeus (not puborectalis)
what vessels does the lateral ligament of the bladder contain?
Conveys superior vesical vessels
what vessels does the lateral ligament of the rectum contain?
Conveys middle rectal vessels
what vessels does the cardinal ligament (rectovesical septum-males) contain?
Conveys uterine vessels & ureters (male & female)
what is the path of the ovarian artery? what does it supply ?
Originates from abdominal aorta
Descends to lateral pelvis, crosses ureter anteriorly
Enters lesser pelvis anterior to external iliac
Enters ovary on lateral aspect
Supplies lateral ovary & tube
superior rectal artery- what does it cross?
Crosses left common iliacs
where do iliolumbar veins drain to? but most pelvic veins drain where? which drain to portal venous system?
Iliolumbar veins drain to common iliac veins
- Most pelvic veins follow arteries and drain to internal iliac veins–> IVC
- superior rectal: portal venous system
what does the obturator nerve supply?
Anterior/posterior divisions supply medial thigh
No pelvic distribution
SNS or PSNS contract internal genitalia?
SNS
SNS or PSNS stimulate erectile bodies?
PSNS
what are the 4 branches (although supply is variable) that can supply blood to ureter in pelvis?
Internal iliac
Superior vesical
Uterine (female)
Inferior vesical (male)
where do visceral afferents from ureters enter the CNS?
Visceral afferents enter CNS at T10-L3
where is the intermediate urethra located? (pelvis or perineum?)
perineum- deep pouch
what is another name for female paraurethral glands? where are they located?
skene’s: anterior wall of vagina, either side of lower urethral opening
(secretions related to pleasure)
internal pudendal crosses exits GSF superior or inferior to piriformis?
inferior
what arteries anastomose for rectal supply?
superior rectal (From IMA) Anastomoses with middle/inferior rectals
what is included in sacral plexus? where do most exit?
L4-S4 ventral rami
most exit GSF
what kind of fibers form the internal urethral orifice? what about internal urethral sphincter in males?
Radial fibers in neck form internal urethral orifice
Circular fibers form internal urethral sphincter in males
what is the inferior rectal nerve also known as ?
inferior ANAL nerve
