Title: Bone Wizardry / OMM Mastery / 6.Sacrum and innominates
Tags: #BW_OMM::Region::Sacrum_Innominates #BW_OMM::Type::Cloze BoneWizardry bonewizardry-free omm omt #Innominate #Sacrum #motion #Torsions #Muscles #Piriformis #ligaments #shear #Articulation #inflares #outflares #primary #secondary
On every note of this deck, unless a note says otherwise:
Topic: Sacrum and innominates
Review Links: - Bone Wizardry sacral diagnosis
- Practice: Sacrum and Innominates QBank
Show outside sources
- MET for sacral dysfunction
- Articulatory sacral rocking
- BLT/LAS procedure
- AAFP hip evaluation

Q: The innominate is composed of [...] fused bones.
A: three
Q: The innominate is composed of the:
1. [...]
2. [...]
3. [...]
A: ilium; ischium; pubis
Bone Wizardry Lock: Three bones fuse into one innominate: ilium, ischium, and pubis. A board question asking how many bones form the hip bone or which three bones compose it - this card covers both answers.

Q: The three bones of the innominate fuse by age [...].
A: twenty
Bone Wizardry Lock: Ilium, ischium, and pubis are three distinct bones early in life. They fuse into the single innominate by age 20. That developmental timeline is the testable fact on this card.

Q: The sacrum is composed of [...] fused vertebrae.
A: five
Q: The anterior portion of the first segment (S1) is referred to as the [...].
A: sacral promontory
Q: The [...] portion of the first segment (S1) is referred to as the sacral promontory.
A: anterior
Q: The [...] is the top most part of the sacrum.
A: sacral base
Q: The [...] is the bottom part of the sacrum.
A: sacral apex
Q: The sacral sulci are located on the [...] part of the sacrum.
A: superior lateral
Q: The [...] are located on the superior lateral part of the sacrum.
A: sacral sulci
Q: The inferior lateral angles (ILAs) of the sacrum are located at the [...] part of the sacrum.
A: inferior lateral
Q: The [...] of the sacrum are located at the inferior lateral part of the sacrum.
A: inferior lateral angles (ILAs)
Comment 4: in somatic dysfunctions, the sacral base can be recorded as shallow (or posterior) or deep (or anterior).
Comment 6: They are recorded as posterior (or shallow) or anterior (or deep) in somatic dysfunctions.
Comment 8: They are recorded as shallow (or posterior), deep (or anterior), superior or inferior in somatic dysfunctions.
Comment 9: They are recorded as shallow(or posterior), deep (or anterior), superior or inferior in somatic dysfunctions.
Bone Wizardry Lock: Map these landmarks before tackling sacral diagnosis. Base is the top (S1 level), apex is the bottom. Promontory is the anterior edge of S1. Sulci sit posterolateral at S1. ILAs are the inferior-lateral corners at the apex. Get the anatomy solid and the torsion notation follows.

Q: The innominates articulate with the femur at the [...].
A: acetabulum
Q: The SI joint joins arms at [...].
A: S2
Bone Wizardry Lock: Two articulations anchor the innominate: the acetabulum joins it to the femur, and the SI joint at S2 joins it to the sacrum. Locating the SI joint at S2 is the specific anatomy fact this card tests.

Q: What ligament divides the greater and lesser sciatic foramen?
[...]
A: The Sacrospinous ligament
Bone Wizardry Lock: The sacrospinous ligament is the structure that divides the sciatic notch into the greater and lesser sciatic foramina. On a question asking which ligament makes that division, sacrospinous is the answer.

Q: What ligament is often the first ligament to become painful in lumbosacral decompensation?
[...]
A: Iliolumbar ligament
Q: What ligament stabilizes anterior motion of L5 on the pelvis?
[...]
A: Iliolumbar ligament
Comment 2: First ligament to become injured with innominate somatic dysfunction.
Bone Wizardry Lock: The iliolumbar ligament is the first structure to signal trouble in lumbosacral decompensation. It anchors L5 to the ilium, so any shift at the lumbosacral junction stresses it before anything else.

Q: The [...] pelvic muscles make up the pelvic diaphragm.
A: primary
Q: What muscles are primary pelvic muscles?
1. [...]
2. [...] muscles
A: Levator ani; Coccygeus
Bone Wizardry Lock: Primary pelvic muscles form the pelvic diaphragm. Two muscles only, levator ani and coccygeus. Secondary muscles like piriformis and iliopsoas are a separate category entirely.

Q: What muscles are the secondary pelvic muscles?
1. [...]
2. [...]
3. [...]
A: Iliopsoas; Obturator internus; Piriformis
Q: The iliopsoas muscle receives innervation from the levels of [...].
A: L1-3
Bone Wizardry Lock: Secondary pelvic muscles are where compensatory somatic dysfunction often originates. The iliopsoas is a common culprit. Its L1-3 innervation means thoracolumbar somatic dysfunction can reflexively tighten it.

Q: Action of the piriformis:
1. [...] rotates
2. [...] thigh
3. [...] thigh with hip flexed
A: externally; extends; abducts
Bone Wizardry Lock: Piriformis is an external rotator and extender with the hip in extension. Flex the hip past 60 degrees and it flips to an abductor. Board questions about piriformis action often hinge on that positional switch.

Q: What nerve might run through the piriformis?
[...] nerve
A: Sciatic
Q: A patient with hypertonic piriformis can have sciatica-like shooting pain down the [...].
A: posterolateral thigh into the foot
Comment: The piriformis muscle receives innervation from the levels of S1-2
Bone Wizardry Lock: The sciatic nerve normally passes below the piriformis. In the variant where it runs through the muscle, piriformis tightness compresses the nerve and reproduces pain all the way into the foot, mimicking a disc herniation.

Q: Piriformis [...] can cause buttock pain that radiates down the thigh, but not usually below the knee.
A: hypertonicity
Q: Piriformis hypertonicity can cause buttock pain that radiates down the thigh, but not usually below the [...].
A: knee
Bone Wizardry Lock: Piriformis pain usually stops at the knee. Buttock and posterior thigh pain that does not go below the knee points to piriformis. Pain that shoots into the calf or foot points to a nerve root or disc.

Q: Physiologically, the innominates rotate about the [...] axis of the sacrum during the walking cycle.
A: inferior transverse
Bone Wizardry Lock: During gait the innominates rotate about the inferior transverse axis of the sacrum. The oblique axes are what the sacrum itself engages during dynamic walking motion. Do not mix up which bone is rotating on which axis.

What are the four types of sacral motion?
1. Dynamic
2. Respiratory
3. Inherent/innominate
4. Postural
Q: Respiratory motion - Motion occurs about the [...] axis of the sacrum.
A: superior transverse
Q: The superior transverse axis is located at approximately [...].
A: S2
Q: During inhalation, the sacral base will move [...].
A: posterior
Q: During [...], the sacral base will move posterior.
A: inhalation
Q: During exhalation, the sacral base will move [...].
A: anterior
Q: During [...], the sacral base will move anterior.
A: exhalation
Q: Inherent (craniosacral) motion - Motion occurs about the [...] axis of the sacrum.
A: superior transverse
Q: During craniosacral flexion, the sacral base rotates [...].
A: posteriorly or counternutates
Bone Wizardry Lock: Four motion types, three transverse axes. Respiratory and inherent craniosacral motion both pivot at the superior transverse axis near S2. Postural motion pivots at the middle transverse axis. Dynamic gait motion uses the oblique axes.

Q: During [...], the sacral base rotates posteriorly or counternutates.
A: craniosacral flexion
Q: During craniosacral extension, the sacral base rotates [...].
A: anteriorly or nutates
Q: During [...], the sacral base rotates anteriorly or nutates.
A: craniosacral extension
Q: Postural motion - Motion occurs about the [...] axis of the sacrum.
A: middle transverse
Q: [...] motion - Motion that occurs during ambulation.
A: Dynamic
Q: Weight bearing on the left leg (stepping forward with the right leg) will cause a [...] to be engaged.
A: left sacral axis
Q: Weight bearing on the [...] leg (stepping forward with the right leg) will cause a left sacral axis to be engaged.
A: left
Comment 2: Nutation = Nod forward
Comment 4: As a person begins to bend forward, the sacral base moves anteriorly. At terminal flexion, the sacrotuberous ligaments become taut and the sacral base will move posteriorly.
Comment 5: As weight bearing shifts from one side to the other while walking, the sacrum engages two sacral oblique axes.
Bone Wizardry Lock: Nutation means the sacral base tips anterior and the ILA moves posterior, the sacrum nods forward. Counternutate and the base goes posterior. For dynamic motion, the weight-bearing leg is the side whose oblique axis engages.

Q: Etiology of an anteriorly rotated innominate: [...]
A: tight quadriceps
Q: With innominate dysfunction, the side of the positive [...] is the side of the dysfunction.
A: standing flexion test
Q: Patient presents with the following Physical exam findings:
Standing flexion test: positive on the right
ASIS: inferior on the right
PSIS: superior on the right
What is the somatic dysfunction?
[...]
A: Right anterior innominate
Bone Wizardry Lock: Positive standing flexion marks the side of dysfunction. Anterior innominate rotation: ASIS drops inferior, PSIS rises superior. Tight quadriceps pull the pelvis into anterior tilt and hold it there.

Q: Etiology of Posterior innominate rotation: tight [...]
A: hamstrings
Q: Patient presents with the following Physical exam findings:
Standing flexion test: positive on the right
ASIS: superior on the right
PSIS: inferior on the right
What is the somatic dysfunction?
[...]
A: Right posterior rotated innominate
Bone Wizardry Lock: Posterior innominate rotation is the mirror of anterior: ASIS goes superior, PSIS goes inferior. Tight hamstrings pull the ischium back and down, tipping the bone into that posterior position.

Q: [...]: one innominate will slip superiorly compared to the other.
A: Superior innominate shear
Q: Etiology of a superior innominate shear: can be due to a [...] on the ipsilateral buttock or a [...]
A: fall; mis-step
Q: Patient presents with the following Physical exam findings:
Standing flexion test: positive on the left
ASIS: superior on the left
PSIS: Superior on the left
What is the somatic dysfunction?
[...]
A: Left superior innominate shear
Bone Wizardry Lock: Shear is not rotation. In superior innominate shear both ASIS and PSIS shift in the same direction, both go superior. A fall on one buttock drives the ilium straight up. If the landmarks move in opposite directions, that is rotation, not shear.

Q: [...]: one innominate will slip inferiorly compared to the other.
A: Inferior innominate shear
Bone Wizardry Lock: Innominate shear is a translational displacement, not a rotation. In inferior shear, the affected innominate sits lower than its counterpart at the sacroiliac joint.

Q: [...]: one pubic bone rides superiorly relative to the other at the symphysis pubis.
A: Superior pubic shear
Q: Superior pubic shear etiology: [...] or a [...] rectus abdominis muscle.
A: trauma; tight
Bone Wizardry Lock: The rectus abdominis is the key culprit in superior pubic shear. A tight rectus pulls the pubic ramus up. The two etiologies to know are trauma and a tight rectus abdominis.

Q: [...]: one pubic bone sits inferiorly relative to the other at the symphysis pubis.
A: Inferior pubic shear
Q: Inferior pubic shear etiology: [...] or tight [...]
A: trauma; adductors
Bone Wizardry Lock: Tight adductors are the main non-traumatic driver of inferior pubic shear. They pull the pubic ramus down. The two etiologies are trauma and tight adductors.

Q: [...]: the innominate rotates medially, bringing the ASIS closer to the midline.
A: Innominate inflares
Q: [...]: the innominate rotates laterally, moving the ASIS away from the midline.
A: Innominate outflares
Comment: An inflare presents with decreased distance from the ASIS to the umbilicus.
Bone Wizardry Lock: Inflare = ASIS moves toward the umbilicus, so the ASIS-to-umbilicus distance decreases. Outflare = ASIS moves away from the umbilicus. The ASIS-umbilicus measurement is the key exam finding.

Q: Sacral torsions - Sacral rotation about an [...] axis along with somatic dysfunction at L5.
A: oblique
Q: [...] - Sacral rotation about an oblique axis along with somatic dysfunction at L5.
A: Sacral torsions
Comment: The oblique axis will run through the superior sulcus ipsilaterally, diagonally across the sacrum, through the contralateral ILA.
Bone Wizardry Lock: The oblique axis connects the ipsilateral superior sulcus diagonally to the contralateral ILA. Every sacral torsion is named for the direction of sacral rotation and which oblique axis is engaged.

Q: Sacral Torsion Rules:
Rule #1: When L5 is sidebent, a sacral oblique axis is engaged on the [...] side as the sidebending.
A: same
Q: Sacral Torsion Rules:
Rule #2: When L5 is rotated, the sacrum rotates the [...] way.
A: opposite
Q: Rule #3: The seated flexion test is found on the [...] side of the oblique axis.
A: opposite
Comment: Sacral Torsion Rules:
Rule #1: When L5 is sidebent, a sacral oblique axis is engaged on the same side as the sidebending.
Rule #2: When L5 is rotated, the sacrum rotates the opposite way on an oblique axis.
Rule #3: The seated flexion test is found on the opposite side of the oblique axis.
Bone Wizardry Lock: Rules 1 and 3 are mirror images: sidebending sets the axis on that same side, and the seated flexion test fires on the opposite side. Rule 2 adds the counter-rotation: the sacrum always goes opposite to L5 rotation.

If L5 is FR_RS_R:
-There will be a positive seated flexion test on the left.
-The sacrum will be rotated to the left on a right oblique axis or L on R.
Bone Wizardry Lock: FRR SR: sidebent right locks the RIGHT oblique axis. Rotated right means the sacrum goes LEFT. Seated flexion fires on the opposite side of the axis, so it is positive on the LEFT. That is L on R.

Q: [...] = twisting of two articulating structures (L5 and the sacrum) in opposite directions
A: Torsion
Comment: In sacral torsions, L5 will always rotate in the opposite direction of the sacrum.
Bone Wizardry Lock: In a sacral torsion, L5 and the sacrum always rotate in opposite directions. The dysfunction is named for the direction of sacral rotation first, then the oblique axis it rides on.

Q: In a [...] sacral torsion, rotation is on the same side of the axis.
A: forward
Q: In a forward sacral torsion, rotation is on the [...] side of the axis.
A: same
Q: [...]:
Positive seated flexion test on the right
Right superior sulcus moves anterior
Left ILA moves posterior.
A: Left rotation on a left oblique axis (L on L)
Comment 3: L on L:
Dynamic findings:
Positive seated flexion test on the RIGHT.
Motion (springing) at the right base is present.
Motion (springing) at the left ILA is restricted.
Motion (springing) at the poles of the left oblique axis (left sulcus and right ILA) is restricted.
Negative lumbosacral spring test
L5 will be sidebent left rotated right (NS_LR_R).
Bone Wizardry Lock: Forward torsion: rotation and axis are on the SAME side. L on L means the right sulcus is deep (moves anterior), the left ILA is posterior, and the lumbosacral spring test is negative. Positive seated flexion is on the right.

Q: [...]:
Positive seated flexion test on the left
left superior sulcus moves anterior
right ILA moves posterior.
A: Right rotation on a right oblique axis (R on R)
Comment: Dynamic findings:
Positive seated flexion test on the LEFT.
Motion (springing) at the left base is present.
Motion (springing) at the right ILA is restricted.
Motion (springing) at poles right oblique
sulcus and left ILA is restricted
Negative lumbosacral spring test
L5 will be sidebent right, rotated left (NS_RR_L).
May be helpful to draw the sacrum out.
Bone Wizardry Lock: R on R forward torsion: left sulcus deep (moves anterior), right ILA posterior, positive seated flexion on the left. Negative lumbosacral spring test. L5 is sidebent right and rotated left.

Q: [...]:
Positive seated flexion test on the right
Right superior sulcus moves posterior
Left ILA moves anterior.
A: right-on-left
Bone Wizardry Lock: Backward torsion: rotation and axis are on OPPOSITE sides. Right-on-left means the right sulcus is shallow and posterior while the left ILA is anterior. Positive seated flexion is on the right.

Q: [...]:
Positive seated flexion test on the left
Left superior sulcus moves posterior
Right ILA moves anterior
A: left-on-right
Comment: Static findings: left sulcus shallow, right ILA anterior and slightly superior, and lumbar curve convex left.
Bone Wizardry Lock: Left-on-right backward torsion: left sulcus shallow and posterior, right ILA anterior, lumbar curve convex left. Positive seated flexion is on the left. Rotation and axis are on opposite sides, which distinguishes this from a forward torsion.

Q: [...]: the sacral base moves anterior about the middle transverse axis.
A: Bilateral sacral flexion
Q: Bilateral sacral flexion: the sacral base moves anterior about the [...] transverse axis.
A: middle
Comment: Static findings:
Right and left sulci deep.
ILAs shallow bilaterally.
Increased lumbar curve.
Bone Wizardry Lock: Bilateral sacral flexion: both sulci are deep and both ILAs are shallow. It pivots on the middle transverse axis with no torsion component.

Q: Due to birth mechanics, [...] is a common dysfunction in the post-partum patient.
A: bilateral sacral flexion
Bone Wizardry Lock: The mechanics of delivery push the sacral base forward, so bilateral sacral flexion is the sacral dysfunction you see most often after childbirth.

Q: [...]: the sacral base moves posterior about the middle transverse axis.
A: Bilateral sacral extension
Q: Bilateral sacral extension: the sacral base moves [...] about the middle transverse axis.
A: posterior
Comment: Static findings:
Right and left sulci shallow.
ILAs deeper bilaterally.
Decreased lumbar curve.
Bone Wizardry Lock: Bilateral sacral extension: both sulci are shallow and both ILAs are deep. Lumbar lordosis decreases. Middle transverse axis, no torsion.

Q: Name the axis:
1. [...]
2. [...]
A: Left oblique axis; Right oblique axis
Bone Wizardry Lock: The oblique axis takes its name from its superior anchor point. A positive SFBT on the left means the sacrum pivots on the right oblique axis, not the left.

Q: How can you differentiate between flexed vs extended sacrum?
With [...]
A: backwards bending test or spring test
Bone Wizardry Lock: Two bedside tests distinguish bilateral sacral dysfunctions: the backward bending test and the spring test. Both should give matching results.

Q: If sacral findings become symmetric as patient extends their back, then backward bending test is [...].
A: negative
Q: If sacral findings become asymmetric as patient extends their back, then backward bending test is [...].
A: positive
Q: If sacrum has a spring or bounce with compression then spring = [...]
A: negative
Q: If sacrum has a lack of spring or stiffness with compression then spring = [...]
A: positive
Q: What type of sacral dysfunction will result with - BBT and - spring test?
[...]
A: Flexed
Q: What type of sacral dysfunction will result with a + BBT and + Spring test?
[...]
A: Extension
Comment 3: Therefore it is anterior or flexed
Comment 4: Therefore it is posterior or extended
Bone Wizardry Lock: Negative BBT and negative spring: sacrum stuck in flexion. Positive BBT and positive spring: sacrum stuck in extension. Both tests should agree.

Q: + seated forward bending test will be [...] axis of rotation.
A: opposite
Bone Wizardry Lock: The positive SFBT side is where movement stops. The oblique axis involved is on the opposite side: positive SFBT on left means right oblique axis.