Sacrum and Innominates Flashcards
Sacrotuberous ligament
ILA to ischial tuberosity
tension helps dx SD of innominate and sacrum
Sacrospinous ligament
sacrum to ischial spines
divides greater and lesser sciatic foramen
Iliolumbar ligament
TP of L4 and L5 to medial side of iliac crest
First ligament to become painful in lumbosacral decompensation
Primary pelvic muscles (pelvic diaphragm)
levator ani
coccygeus muscles
Secondary pelvic muscles
partial attachments to true pelvis
Iliopsoas
Obturator internus
Piriformis
Piriformis
Inferior anterior aspect of sacrum to greater trochanter of the femur
externally rotates, extends thigh
when hip flexed - abducts thigh
Innervated by S1 and S2
11 percent of population have entire or fibular portion of sciatic nerve run through the belly
-hypertonicity -> buttock pain that radiates down thigh, but NOT below knee
Innominate mechanics
rotate around inferior transverse axis of sacrum during walking cycle
innominate anterior and posterior dysfunction occur around that axis
Respiratory motion of sacrum
about superior transverse axis of sacrum at S2
Inhalation - base moves posterior
Exhalation - base moves anterior
Inherent (craniosacral) motion
about superior transverse axis of sacrum
craniosacral flexion - base moves posteriorly - counternutates
Craniosacral extension - sacral base moves anteriorly or nutates
Postural motion
about middle transverse axis of sacrum
Bend forward - sacral base moves anteriorly, terminal flexion - sacrotuberous ligaments become taut, base will move posteriorly
Dynamic motion
occurs during ambulation
sacrum engages both oblique axes
Weight bearing on left leg causes left sacral axis to engage
Anterior innominate rotation
rotation about inferior transverse axis of sacrum
Tight quadriceps
ASIS inferior
PSIS superior
Long leg ipsilaterally unless anatomical short leg compensation
Positive standing flexion
ASIS restricted to compression ipsilaterally
Posterior innominate rotation
Rotation about inferior transverse axis
tight hamstrings
ASIS superior
PSIS inferior
Shorter leg ipsilaterally unless compensatory for anatomical long leg
Positive standing flexion
ASIS restricted to compression ipsilaterally
Superior innominate shear (aka innominate upslip, superior innominate subluxation)
fall on ipsilateral buttock or mis step
ASIS and PSIS superior
Pubic rami superior
Shorter leg ipsilaterally
Positive standing flexion
ASIS restricted to compression ipsilaterally
Inferior innominate shear (aka innominate downslip, inferior innominate subluxation)
ASIS and PSIS inferior
Pubic rami inferior
Longer leg ipsilaterally
Positive standing flexion
ASIS restricted to compression ipsilaterally
Superior pubic shear
trauma or tight rectus abdominus
ASIS and PSIS level
Pubic bone superior
Positive standing flexion test
ASIS restricted to compression ipsilaterally
Inferior pubic shear
trauma, tight adductors
ASIS and PSIS level
Pubic bone inferior
Positive standing flexion test
ASIS restricted to compression ipsilaterally
Innominate inflares
innominate rotate medially
ASIS more medial, less distance between ASIS and umbilicus
Ischial tuberosity more lateral
Positive standing flexion
ASIS restricted to compression ipsilaterally
Innominate outflares
Innominate rotate laterally
ASIS lateral - distance between ASIS and umbilicus increased
Ischial tuberosity more medial
positive standing flexion
ASIS restricted to compression ipsilaterally
Sacral torsion rules
1: L5 sidebending engages sacral oblique axis on same side
2: L5 rotation -> sacrum rotating opposite way on an oblique axis
3: seated flexion found on opposite side of oblique axis
Forward sacral torsion - L on L
right super sulcus moves anterior, ILA moves posterior
Right sulcus deep
Left ILA posterior, slightly inferior
Lumbar curve convex to right (sidebent left)
Positive seated on right
Springing motion restricted on Left ILA, poles of left oblique axis
negative lumbosacral spring test
L5 will be NSlRr
Forward sacral torsion - R on R
right rotation as left superior sulcus moves anterior, right ILA moves posterior
Left sulcus deep
right ILA posterior and slightly inferior
Lumbar curve convex to left (sidebent right)
Positive seated on left
springing restricted on right ILA, poles of right oblique axis
Negative lumbosacral spring test
L5 will be NSrRl
Backward sacral torsion - R on L
right superior sulcus moves posterior, left ILA moves anterior
right sulcus shallow
Left ILA anterior and slightly superior
Lumbar curve convex to right (side bent left)
Positive seated on right
Spring restricted at right base, poles of left oblique axis
Positive lumbosacral spring test
positive backward bending test
L5 will be nonneutral, SlRl
Backward sacral torsion - L on R
Left superior sulcus moves posterior, right ILA moves anterior
Left sulcus shallow
Right ILA anterior and slightly superior
Lumbar curve convex left (sidebent right)
Positive seated flexion on left
Springing restricted at left base, poles of right oblique axis
Positive lumbosacral spring test
Positive backward bending test
L5 will be nonneutral, SrRr
Bilateral sacral flexion
entire sacral base moves anterior about middle transverse axis
Right and left sulci deep
ILAs shallow b/l
Increased lumbar curve (lordosis)
False negative seated flexion - no asymmetry
Springing restricted at both ILAs
Negative lumbosacral spring test
common dysfunction in post-partum patient
Bilateral sacral extension
Entire sacral base moves posterior about middle transverse axis
Right and left sulci shallow
ILAs deeper b/l
decreased lumbar curve (lordosis)
false negative seated flexion - no asymmetry
Springing restricted at base - b/l sulci
Positive lumbosacral spring test
unilateral sacral flexion
sacrum shifts anteriorly around transverse axis
Ipsilateral findings:
deep sulcus
ILA significantly inferior, slightly posterior
Positive seated flexion
spring restricted at ILA
Unilateral sacral extension
sacrum shifts posteriorly around transverse axis
Ipsilateral findings:
shallow sulcus
ILS significantly superior, slightly anterior
positive seated flexion
Spring restricted at sulcus
Positive lumbosacral spring test
Positive backward bending test
