Sacrum Flashcards
sacrum fusion
age 25
sacral base
top
apex
bottom of sacrum
sacral promontory
anterior portion of S1
ligaments of sacrum
iliolumbar**
sacrospinous
sacrotuberous
A/P sacroiliac
to ischial tuberosity
hamstrings
tight hamstrings
sacral dysfunction
sarcum and uterus
connected
muscles that move sacrum
no one really knows
-no muscles move sacrum directly**
pull of ligaments
piriformis, iliacus, pelvic diaphragm, aponeurosis of erector spinae
piriformis
external rotator of thigh
innervation S1-2
intimate relationship to sciatic nerve
lumbosacral angle
24-35 degree angle
increased in obese and pregnant
sacral sulci
medial and superior to PSIS
ILA
most posterior aspect of the sacrum
ILAs alone
can distinguish shear
axes of motion
7 total**
1 vertical
1 A/P
3 transverse
2 oblique
superior transverse axis
respiratory axis
S2
middle transverse axis
sacroiliac axis
S3
flex/extend motion of sacrum on ilium
inferior transverse axis
iliosacral axis
S4
flex/extend motion of ilium on sacrum
exhalation
sacrum flexion
lumbar lordosis increases
inhalation
sacrum extension
lumbar lordosis decreases
oblique axis
named for superior aspect they exit
sacral sulcus
superior portion
walking
torsional motion
weight on left foot
- sacrum rotates right on right oblique axis
- lumbar sidebends right
4 things to know
what feeds it (neurovascular)?
whats its origin and insertion?
whats its reflex?
seated flexion test
for sacrum
**feet flat on floor
tests S3 motion
side of dysfunction and opposite axis in sacral torsion**
standing flexion test
for innominate
sheers
side restricted is side of dysfunction
positive spring test
sacrum stuck backwards
negative spring test
sacrum moves forward
backward bending test
sphinx test
sphinx test
creates lumbar extension and sacral flexion
negative BBT
findings improve
- sacrum likes flexion
- direction of ease is forward
positive BBT
findings do not improve
- sacrum stuck in extension
- base stuck backwards
motion testing
anterior pressure on ILAs and sulci
L5 rules**
- sacral oblique axis will be to same side as L5 sidebending
- sacrum rotates opposite L5
- seated flexion test is positive on opposite side of oblique axis
SI joint dysfunction
can shorten stride
- inhibit gluts
- activates/overuse hamstrings
quadratus lumborum
stabilizer of L-spine
- activated - pulls on iliolumbar ligaments
- lower back pain
- jammed butt syndrome - jump one leg constantly
fascial connections
foot to thoracolumbar region
gait sacrum
foot flat - symmetric midstance (right) - left on left torsion bipedal - symmeric midswing - right on right torsion right terminal swing - sacrum symmetrical
right on right sacral torsion
negative spring
improve on BBT
right on left sacral torsion
positive spring
do not improve on BBT
unilateral sacral flexion shear
negative spring
improve on BBT
unilateral sacral extension shear
positive spring
do not improve on BBT
bilateral sacral shear
negative seated flexion
sulci equal
ILAs equal
positive spring - extension
-BBT fail to improve
negative spring - flexion
-BBT improve
+BBT
does not improve
-BBT
improves
bilateral extension
positive spring
BBT fail to improve
bilateral flexion
negative spring
BBT improve
