lecture 4 pelvis Flashcards
components of pelvic girdle
right and left hip bones, sacrum, pubic symphysis
what connects sacrum and hip bone
sacro-iliac joint - no movement
what is the pubic angle; narrow in males, wide in females
angle between pubic symphysis (no movement) and inferior rami of the ischium
structure of hip bone
3 bones: ilium (main bone beneath iliac crest), pubis (anterior), ischium (posterior); fuse forming acetabulum and acetabular fossa (depressed area with articular surface)
what is the false/greater pelvis
superior to margin of pelvic inlet; iliac fossa, ASIS
what is the true/lesser pelvis
inferior to margin of pelvic inlet; sacrum, coccyx, pubic tubercle, ischiopubic ramus, ischial tuberosity
what 3 foramen are present in true pelvis
greater and lesser sciatic foramen; obturator foramen
what ligament connects sacrum to ischial tuberosity
sacrotuberous ligament
what ligament connect sacrum to spine
sacrospinous ligament
what makes up the pelvic wall
sacrum and coccyx, pelvic bones, sacrospinous and sacrotuberous ligaments
what angle is the pelvic cavity axis back from abdominal cavity axis
45 degrees
what is the boundary between abdominal and pelvic cavities
pelvic inlet
what is the boundary of the end of the pelvis (before reaching perineum)
pelvic outlet
what is the pelvic inlet comprised of antero-laterally
pubic tubercle, pubic symphysis, linea terminalis. sacrum
what are the 3 sections of the linea terminalis
pubic crest, pecten pubis, arcuate line
what are the boundaries of the pelvic outlet
coccyx, sacrotuberous ligament, ischial tuberosity, body of pubis, pubic symphysis, pubic arch
what forms a shallow basin containing the lower abdominal viscera
iliac fossae
what way is the axis of the pelvic cavity inclined
antero-inferiorly
what shape is the pelvic cavity
conical or cylindrical (birth canal)
what mainly lines pelvic cavity
muscles, posteriorly with nerves and blood vessels
what is most of the pelvic bone facing pelvic cavity covered by
obturator internus muscle and its fascia
nerves which supply lower limb and lower part of pelvis
lumbosacral plexus
what 2 muscles are attached to the medial surface of the greater tochanter of femur
piriformis (from sacrum), obturator internus (from bony margins of obturator foramen)
what is the border between obturator internus and levator ani muscle (from where levator ani muscle originate)
tendinous arch (obturator internus fascia)
what are the 3 sections of the levator ani muscle
iliococcygeus, pubococcygeus, puborectalis
what muscle is posterior to levator ani and anterior to the sacrospinous ligament
coccygeus
what ligament is formed from levator ani muscle medially
anococcygeal ligament
what do the levator ani muscles form
pelvic diaphragm (is a bowl-like sheet of muscle)
function of levator ani muscles
support pelvic organs
what are the pelvic organs
bladder, cervix/uterus, rectum
pelvic diaphragm nerve supply
pudendal (S2-S4; from perineum) and directly by S4
slide 12
slide 12
openings in pelvic diaphragm (anterior to posterior)
urethra, vagina in females (both in perineal membrane in urogential triangle), anal canal (no perineal membrane; levator ani in anal triangle)
what is the perineal membrane
inferior layer of fascia of urogenital part of pelvic diaphragm (attach to ischio pubic ramus), where most pelvic organs are attached
what is the perineal body
fibromuscular mass
slide 13
slide 13
where is levator ani slung from
pelvis and sacrum
what is located beneath the diaphragm
perineum
what does the perineum contain
voluntary sphincters, external genitalia
where are structures in lower urinary system (ureter, urinary bladder, urethra) located
pelvic cavity
slide 16
slide 16
what 2 structures are present only in the male pelvis
ductus deferens (passes across ureter), prostate gland (inferior to urinary bladder, above urogenital diaphragm)
function of ductus deferens
carries sperm from the epididymis to the ejaculatory duct
slide 17
slide 17
structure of male pelvis (superior to inferior)
urinary bladder, prostate
what lines prostate on either side running obliquely
levator ani
what is outside of pelvic cavity formed by levator ani
ischio-anal fossa
slide 18
slide 18
urethral sphincters (male)
internal vesicae urethral sphincter (smooth muscle) immediately below bladder at neck; external urethrae urethral sphincter (skeletal muscle) in deep perineal pouch directly below prostate in perineum
slide 19
slide 19
structure of female pelvis
ureter runs medial to ovary, posterior to uterus into urinary bladder and out through short urethra (near vagina)
what is posterior to anal canal
levator ani
slide 20
slide 20
urethral sphincters (female)
not well organised internal urethral sphincter, external urethral sphincter (skeletal muscle) surrounds utethra in deep perineal pouch
2 additional groups of muscle in females
sphincter urethrovaginalis, compressor urethrae
slide 21
slide 21
shape of bladder when empty
tetrahedral
structures at supero-posterior corners
ureters
structure at anterior corner (apex)
median umbilical ligament
slide 22
slide 22
what angle does urethra leave
inferior
what covers superior surface of urinary bladder
peritoneum
what does urinary bladder expand between
transversalis fascia, lining peritoneum
blood supply of rectum
superior, middle and inferior rectal arteries
shape of rectum
double-S bend to keep load off sphincter
slide 24
slide 24
what nervous system supplies rectum and what is it sensitive to
ANS visceral, mainly sensitive to filling
what nervous system supplies anal canal and what is it sensitive to
somatic nerves, extremely sensitive to injury
what is the boundary between rectum (ampulla) and anal canal
anorectal junction
sections of external anal sphincter
deep superficial, subcutaneous
slide 25
slide 25
importance of sphincter ani (skeletal muscle) surrounding anal canal
less important to faecal continence than puborectalis part of levator ani (sharp angle into recto-anal junction)
what can injure puborectalis part of levator ani
badly-performed episiotomy
slide 26
slide 26
what does rectum descend within
concavity of sacrum
how many lateral curvatures does rectum show
3
where is a right-angle bend
recto-anal junction
2 sphincters of rectum
smooth muscle internal, skeletal muscle external
main functional sphincter
puborectalis sling of levator ani
arterial supply of all pelvic organs (except ovaries), pelvic walls and much of gluteal region
internal iliac artery (anterior and posterior divisions); anterior go to visceral structures; posterior go to gluteal muscles
where does common iliac artery form
L4
when does common iliac artery divide into internal and external iliac arteries
L5/S1
where does external iliac go to
lower limb
what artery supplies genital structures in perineal region
pudendal artery which is a branch of internal iliac artery
