MS III SI joint 1
Card Set Information
MS III SI joint 1
3 bones and 3 joints of the pelvis
: 2 innominates and a sacrum
: 2 SI jts and the pubic symphysis
iliac bone's surface where it interacts with the sacrum
concave posterosup, and around the rim, except inf -- it's an upside down horse-shoe of concavity
a crest btwn 2 furrows
ilium and sacrum, which has the thicker end plate?
ilium, with lots of proteoglycans with collagen making up the fibrocartilage covering the joint
shape of sacrum where it interacts w iliac
corresponds to iliac... has a furrow bordered by 2 crests
how does the hyaline cartilage compare, sacrum to iliac?
it's 2-3x thicker on the sacrum (this asymmetry isn't seen anywhere else)
inguinal lig attachments
pubic tubercle --> ASIS
iliolumbar lig attachments
TP of L4-5 to the iliac crest's inner lip on the
only in bipedal animals
not present in humans until 2nd decade of life
thought to dev from a sprig of QL
iliolumbar lig blends with what lig?
anterior SI lig
which pelvic lig pulls the lumbar spine into rot and how?
iliolumbar lig -- it runs from iliac crest to L4-5 TPs, so if the innominate goes into post tilt it pulls on the lig which pulls on the spine
sacrospinous lig attachments
ischial spine --> lateral region sacrum and coccyx
deep (ant) to sacrotub lig,
shares fiber space with sacrotub ligament.
sacrospinous lig roll
works with sacrotuberous ligament to stop ilium rotation while allowing posterior rotation.
They're most notably stressed when a person leans forward or stands up.
This pair of ligaments converts the greater and lesser sciatic notches into the greater and lesser sciatic foramens.
sacrotuberous ligament attachments
sacrum (TPs down to upper coccyx)--> ischial tub
(remember, the hammies attach to ITs, so there's a rel w/biceps femoris)
ant SI lig attachments and description
anterior surface of the lateral part of the sacrum --> margin of the auricular surface of the ilium and to the preauricular sulcus
ant to SI jt
described as a sling holding the front of the sacrum
CAN be injured and cause pain, but hard to diagnose bc can't be palpated
posterior sacroliliac lig
about the layers...
short interosseous lig
: deepest, most horizontal
: takes up most space, running from the post arch of sacrum to mid-ilium, overlying most of the posterior part of the joint (superolat)
long posterior SI lig
: from 3rd transverse tubercle of sacrum to the PSIS, has more vertical fibers, adding stability to the joint
what kind of joint is the pubic symphysis?
secondary cartilagionous joint, amphiarthrosis
ligament connecting the pubic symp, and what's in it?
interosseous lig (ant, post, and sup ligs), with a fibrocartilagionous disc in the middle
what happens on each of the 3 horiz axes of the sacrum
sup (by the base) -- respiratory tipping
middle -- nutation (top tips ant) and counternutation
inf - flex/ext ??
sacrum functions as an atypical ___
SI jts function as atypical ___
the innominate is functionally considered UE or LE?
ILA - what is it?
inferior lateral angle -- the lateral dips at the bottom of the sacrum -- they're like atypical TPs
bodies of T12-L3 (psoas) + inner iliac crest (iliacus) --> lesser troch
last rib and TPs of lumbar vert -->iliac crest and iliolumbar lig