Pelvic Walls and Floor Flashcards
what bones form the pelvis?
right and left innominate bones with the sacrum in the middle
where is the greater sciatic notch?
between the ala of the innominate bones and ischial spine
what does the greater sciatic notch transmit?
piriformis superior gluteal vessels and nerves inferior gluteal vessels and nerves sciatic nerve posterior femoral cutaneous nerve internal pudendal artery and vein nerve to obturator internus nerve to quadratus femoris
what does the external surface of the ischial spine give attachment to?
gemellus superior
what does the internal surface of the ischial spine give attachment to?
coccygeus
levator ani
pelvic fascia
what does the pointed extremity of the ischial spine give attachment to?
sacrospinous ligament
what attaches to the ischial spine?
gemellus superior coccygeus levator ani pelvic fascia sacrospinous ligament
where is the lesser sciatic notch?
between the ischial spine and ischial tuberoisty of the innominate bones
what ligaments convert the lesser sciatic notch into the lesser sciatic foramen?
sacrotuberous and sacrospinous ligaments
what does the lesser sciatic notch transmit?
tendon of obturator internus
nerve to obturator internus
pudendal nerve
internal pudendal vessels
what does the lower portion of the ischial tuberosity give attachment to?
outer: adductor magnus
inner: sacrotuberous ligament
what does the upper portion of the ischial tuberosity give attachment to?
upper + outer: semimembranosus
lower + inner: long head of biceps femoris and semitendinosus
what does the obturator foramen transmit?
obturator artery, vein and nerve (out of the pelvis)
where does the sacrospinous ligament run from and to?
ischial spine (pointed extremity) to sacrum
where does the sacrotuberous ligament run from and to?
sacrum to upper and inner portion of the ischial tuberosity
what type of joint is the pubic symphysis?
secondary cartilaginous
what articulates at the pubic symphysis?
left and right innominate bones
what type of joint is the lumbosacral joint?
secondary cartilaginous
what articulates at the lumbosacral joint?
L5 and the sacrum
what articulates at the sacroiliac joint?
sacrum and iliac crest
what ligaments hold together the sacroiliac joint (and what type of joints do they create)?
anterior sacroiliac ligament: synovial
posterior sacroiliac ligament: fibrous
what ligaments convert the greater sciatic notch into the greater sciatic foramen?
sacrotuberous and sacrospinous ligaments
what forms the anterior boundary of the pelvis?
pubic bodies
pubic rami
pubic symphysis
what forms the posterior boundary of the pelvis?
sacrum
coccyx
piriformis
what forms the inferior boundary of the pelvis?
muscular sheet forming the pelvic boundary
what forms the superior boundary of the pelvis?
there is no boundary - it’s an open space!
what is the difference in the shape of the innominate bones in males vs females?
males: acute angle at pubic symphysis, higher ala and smaller pelvic inlet
females: obtuse angle at pubic symphysis, flatter ala and wider pelvic inlet
what is iliacus found?
iliac fossa, then joins with the psoas and iliopsoas –> lesser trochanter of femur
what is the function of iliacus?
hip flexion
what is the innervation of the iliacus?
femoral nerve (L2-4)
where is psoas?
bodies and IV discs of L1-5 (deep) and of T12-L4 (superficial) –> lesser trochanter of the femur, after joining with the iliacus and iliopsoas
what are the functions of psoas?
one: bend trunk laterally
both: raise trunk from supine position
what is the innervation of psoas?
anterior rami L2-4, from lumbar plexus
where is obturator externus?
outer surface of obturator membrane –> trochanteric fossa of femur
what is the function of obturator externus?
lateral rotation and stabilisation of hip
what is the innervation of obturator externus?
posterior branch of obturator (L3+4)
where is obturator internus?
inner surface of obturator membrane –> trochanteric fossa of femur, passes through lesser sciatic foramen
what is the function of obturator internus?
lateral rotation of hip
what is the innervation of obturator internus?
nerve to obturator internus, direct from sacral plexus (L5+S1)
where is piriformis?
pelvic surface of sacrum –> greater trochanter of femur
where is the function of piriformis?
lateral rotation of hip joint
what is the innervation of piriformis?
nerve to piriformis, direct branch from sacral plexus (S1+2)
what muscle forms the roof of the anal triangle?
levator ani
what muscles form the pelvic diaphragm?
levator ani
coccygeus
what is the function of the pelvic diaphragm?
muscular floor to prevent prolapse
where is coccygeus?
ischial spine and sacrospinous ligament –> coccyx and inferior sacrum
what is the function of coccygeus?
flexion of coccyx
support pelvic viscera
what is the innervation of coccygeus?
direct branches from the sacral plexus (S4+5)
what are the two parts of levator ani?
pubococcygeus and iliococcygeus
what are the roles and movements of levator ani?
supports pelvic viscera
contract during forced expiration, coughing etc.
relaxes to allow urination and defecation
which part of levator ani is formed of the most medial fibres?
pubococcygeus
which part of leavtor ani is formed of the more lateral fibres?
iliococcygeus
what is the role of pubococcygeus?
support the vagina/prostate gland and rectum
where does the pubococcygeus attach?
vagina/prostate gland and rectum
what are the three divisions of pubococcygeus?
puborectalis
levator prostate (puboprostaticus)
pubovaginalis
where is the puborectalis found?
around the rectum
where is the levator prostate (puboprostaticus) found?
around the prostate (male only)
where is the pubovaginalis found?
around the vagina (female only)
where is the iliococcygeus found?
anterior to coccygeus, posterior to pubococcygeus
what innervates pubococcygeus?
pudendal nerve (S2-4) nerve to levator ani (S4)
what component of pubococcygeus is found in males, and where do its fibres run?
most medial pass around the prostate and insert into perineal body (levator prostate)
what component of pubococcygeus is found in females, and where do its fibres run?
most medial fibres pass around the vaina and insert into perineal body (pubovaginalis)
what component of pubococcygeus is found in both sexes, and where are it’s fibres found?
fibres mix with those from the external anal sphincter, modified as a sling around the rectum (puborectalis)
what is the function of puborectalis?
maintain faecal continence, especially important after the rectum has filled (so internal anal sphincter open)
what is the anococcygeal raphe and where is it found?
connective tissue in the floor of the pelvis, between the coccyx and the posterior margin of the anus
fibres of what form the anococcygeal raphe?
levator ani as they unite with the muscle on the opposite size
where does the iliococcygeus attach?
fascia of obturator internus and anococcygeal raphe
which of the iliococcygeus and pubococcygeus is more fibrous?
iliococcygeus
what name is given to the area of the fascia of obturator internus that levator ani attaches to?
tendinous arch of levator ani
what is the perineal body composed of?
fibrous connective tissue
what attaches to the perineal body?
levator prostate
pubovaginalis
external anal sphincter
perineal muscles
what is the equivalent of the perineal body between the anus and coccyx?
anococcygeal raphe
where is the perineal body found?
females: between the anus and vulva
males: between anus and scrotum
what does the parietal pelvic fascia cover?
the internal pelvic wall
what does the thickened portion of parietal pelvic fascia over the obturator internus form?
tendinous arch of the pelvis (and levator ani)
what does the anterior portion of parietal pelvic fascia give rise to in males?
puboprostatic ligament
what does the anterior portion of parietal pelvic fascia give rise to in females?
pubovesical ligament
what does the visceral pelvic fascia cover?
pelvic organs
what does the lateral extension of visceral pelvic fascia from the vagina to the tendinous arch give rise to?
the paracolpium (the vascular and connective tissue alongside the vagina)
at what point does the parietal and visceral pelvic fascia blend?
when the organs pierce the pelvic floor
what is the role of the endopelvic fascia?
packing material around the organs
what are the two basic types of endopelvic fascia?
loose and condensed
where is the loose endopelvic fascia found?
in the spaces in the pelvis
e.g. retropubic (pre-vesical) space
what is the condensed fascia formed of and where is it found?
thickenings of the endopelvic fascia, the primary condensation is the hypogastric sheaths running along the posterolateral walls of the pelvis
