Anatomy of pelvis and perineum Flashcards
Sacrotuberous ligament
re-enforces the sacroiliac jt.
runs from the posterior sacrum to the ischial tuberosity
helps create the lesser sciatic foramen with the sacrospinous ligament
Sacroiliac joint
R and L
reinforced by the anterior, posterior, and interosseous sacroiliac ligaments
allows for gliding and rotary motion (interosseous and sacrotuberous lig resist rotary motion)
sacrospinous ligament
runs b/w the ischial spine and the inferior sacrum
creates the greater sciatic foramen above and the lesser sciatic foramen below (along with the sacrotuberous ligament)
obturator canal
the open portion of the obturator foramen (ant sup.) that is not covered by obturator membrane
terminal line
aka pelvic brim
above the line is major (false pelvis)-
below=minor (true) pelvis
the plane of the line is the superior aperture or the pelvic inlet
approx 50-60 deg angle
pelvic outlet
inferior aperture from the tip of the coccyx to the inferior part of the pubic symphysis
made up of the lower irregular border of the pelvis, where structures like the urethra, anus, and vagina exit
anatomical orientation of the pelvis
pelvic brim is tipped 50-50 deg from horizontal
base of sacrum is 4 in higher than the symphysis
ASIS and PS are in the SAME VERTICAL PLANE
female pelvis
shallower major pelvis with everted iliac crests
shallower and wider minor pelvis with greater diameter
everted sciatic tubers (larger sciatic notch)
broader sacrum with less curve
superior aperture is more oval
subpubic angle is greater
True conjugate diameter
from the sacrovertebral angle to superior margin of the symphysis
diagonal conjugate
from sacrovertebral angle to inferior margin of the symph
transverse diameter of pelvis
greatest width of the superior aperature
oblique diameter
from sacroiliac articulation of one side to the iliopectineal eminence of the contralateral side (1/2 the ramus
transverse diameter of the inferior aperture
b/w the inner surfaces of the ischial tuberosity
anterior sagittal diameter of the inferior aperture
from the transverse diameter to they symph
posterior sagittal
from the transverse diameter to the symph
android pelvis
most common pelvis
heart shaped inlet
anthropoid pelvis
2nd most common in males
exaggerated a/p inlet
gynecoid pelvis
most common in females
oval shaped pelvic inlet
platypelloid
least common in both sexes 3% of all females
exaggerated transverse inlet diameter
flat pelvic inlet
Obturator internus
O: inner surface of the obturator membrane and rim
I: greater troch
A: external rotation of thigh
N: n. to obturator internus
leaves pelvis as a tendon that passes along the lesser sciatic notch covered by obturator fascia
Piriformis
O: sacrum I: greater trochanter A: ext rot and abduction n: S1 and S2 ventral rami passes thru the greater sciatic foramen
Levator ani: pubococcygeus
O: pubis I: coccyx and anococcygeal ligament A: supports the pelvic viscera N: perineal branches of S3 and 4 anterior to the rectum and right and left portions are separated
urethra of both sexes passes thru its opening
Ilicoccygeus m.
O: ilium (arcus tendineus)
I: coccyx and anococcygeal ligement
A: perineal branches of S3-4
N: supports the pelvic viscera
puborectalis
O: pubis
I: puborectalis m of the other side, form circular sphincter
A: supports viscera, maintains anorectal junciton
N: sacran n 3-4
coccygeus
O: ischial spine and sacrotuberous lig. I: coccyx and lower part of sacrum I: S4 and 5 Ventral rami A: supports pelvic viscera most poster muscle of the pubic diaphragm
Peritoneum of the peovis
does not contact the floor of the pelvis
does not contact the floor and walls of pelvis, draped over the superior aspects of the structures
rectovesicular pouch
fold in the male b/w the rectum and the bladder
place for fluid to fill
Rectouterine pouch
in the females, between the rectum and the uterus
vesicouterine pouch
b/w the superior aspect of the urinary bladder and the uterus
Boarders of the perineum
anterior: pubis
lateral: ishiopubic rami and ischial tuberosities
posterior: coxyx and sacrum
post/lat: sacrotuberous lig
superior: separated from the pelvic cavity by the pelivic diaphragm
UG diaphragm
stretches anterior b.w the two ischipubic rami creating a urogenital and anal triangles
UG diaphragm
muscular sheet b/w the ischipubic rami
composed of sphincter urethrae (anterior) (aka urethrovaginalis)
and deep transverse perineal muscle
anterior portion is open for the deep dorsal vein of the penis
fascia surrounds superior and inferior surface
inferior fascia of UG diaphragm
known as perineal membrane
lines the internal surface of the UG diaphragm
Superficial perineal space
deep to skin, inferior to perineal membrane (colle’s fascia)
contains sex stuff (erectile bodies, musculature, vessels, nn.)
Deep perineal space
space b/w inf and sup fascia
contains muscles of the UG diaphragm
vessels and nn.
