OMM

Sacral diagnosis from landmarks and motion

Build sacral diagnoses from sulci, inferior lateral angles and motion tests, distinguish torsions from shears, and choose safe treatment principles.

A deep right sulcus and a posterior left inferior lateral angle can fit two different sacral torsions. The landmarks suggest left rotation. They do not tell you whether the axis is left or right. That is the first distinction to keep in view.

Read the landmark pattern, identify the restricted motion, then name the diagnosis. Use a contradictory finding as a reason to recheck, not as a detail to discard.

Find the sacrum before naming its position

The sacral base is superior, beneath L5. The apex is inferior, above the coccyx. The sacroiliac joints connect the sacrum to the ilia on either side. The posterior superior iliac spines, or PSISs, belong to the ilia. They are reference landmarks, not corners of the sacrum. The inferior lateral angles, or ILAs, lie where the lower lateral sacral borders curve medially near S5. [1]

Palpate sulcus depth just medial to the PSIS region and compare the two sides using consistent pressure. A relatively deep sulcus indicates that the underlying sacral base is relatively anterior. A relatively shallow sulcus indicates a posterior base. At the ILAs, record anterior versus posterior and superior versus inferior. A posterior/inferior ILA is not the same finding as an anterior/superior ILA.

Superior landmarks

Patient left sulcus | Patient right sulcus

Compare depth of the sacral base beneath the examining fingers.

Inferior landmarks

Patient left ILA | Patient right ILA

Compare prominence and height of the lower lateral sacral borders.

Posterior-view landmark key. When you face the patient's back, the patient's left is on your left and the patient's right is on your right. Anterior means deeper toward the table in a prone patient; posterior means toward the examiner. This is a relational map, not a scale drawing.

The four-point comparison is useful only if you keep the observations equivalent. “Right sulcus deeper than left” also means “left sulcus shallower than right.” Likewise, “left ILA posterior relative to right” can be expressed as “right ILA anterior relative to left.” These are relative comparisons; neither proves that the apparently less prominent side is normal. Never switch from sulcus depth to ILA depth without saying which structure you mean. [2]

Sacral flexion, or nutation, describes anterior and inferior displacement of the base with the apex directed posteriorly. Sacral extension, or counternutation, reverses that relationship. These terms refer to the sacrum. Lumbar extension in the sphinx position can encourage sacral nutation, so lumbar extension and sacral extension are not synonyms. [2] [3]

Try it here · Checkpoint 1 of 3

Make your prediction before reading the choices. A first attempt is just a starting point.

Case 12

Show answer and explanations

A. Left unilateral extension (Best answer)
A relatively deep right sulcus means relatively shallow left. Combined with an anterior left ILA and left lateralization, this supports left extension.
B. Left-on-left torsion (Why this does not fit)
The deep-right finding alone suggests left rotation only if the opposite-corner torsion geometry is present. Here the left ILA is anterior, not posterior.
C. Right unilateral flexion solely from the deep right sulcus (Why this does not fit)
Right-sided relative flexion landmarks are not enough to name that side; left-positive seated flexion and positive spring support left extension.
D. Right-on-left torsion (Why this does not fit)
This would need posterior/inferior right ILA with a deep left sulcus and right lateralization, not the stated combination.

Takeaway: Convert paired comparisons before assigning a category or side.

Case sources: [2] [3]

Give each test one job

Seated flexion asks about asymmetric excursion

With the patient seated on a stable surface and feet supported, compare thumb excursion beneath the PSISs during forward bending. The side that travels farther superiorly is conventionally called positive. Sitting reduces lower-limb influences; it does not perfectly isolate one joint. The test lateralizes a pattern and must be interpreted with the rest of the examination.

For a torsion, the positive seated-flexion side is opposite the named oblique axis. For unilateral sacral flexion or extension, it is on the named dysfunctional side. Do not apply the torsion-axis rule until the landmarks support a torsion. Otherwise a right unilateral flexion would be incorrectly assigned a left oblique axis. [1] [2]

Spring tests anterior compliance

A gentle lumbosacral spring assessment asks whether the sacral base can yield anteriorly. A negative test has compliant spring. A positive test has reduced spring or resistance to anterior motion. Within the conventional diagnostic model, posterior torsions and extension dysfunctions have a positive spring. Forward torsions and flexion dysfunctions have a negative spring. A negative spring alone can also occur in a normal examination.

Sphinx compares the response to lumbar extension

Compare the sacral landmarks prone and then with the upper body supported on the elbows if tolerated. For an initially asymmetric pattern, improved symmetry supports a forward torsion or unilateral flexion; persistent or increased asymmetry supports a backward torsion or unilateral extension. A symmetric bilateral pattern may remain symmetric in sphinx, so symmetry alone cannot distinguish bilateral flexion, bilateral extension and a normal examination. Assess anterior compliance and the restricted direction as well. Describe what changed. Pain on lumbar extension by itself does not prove a backward torsion, because other lumbar conditions can hurt in that position. [2] [3]

A negative seated flexion test does not rule out sacral dysfunction. Symmetric bilateral restriction may produce no lateralizing difference. Conversely, two equal sulci are not automatically dysfunctional. Look for reproducible restriction, tissue findings and an appropriate clinical context.

Standing flexion is traditionally used in the innominate examination. An anterior innominate rotation is supported by an inferior ASIS and superior PSIS on the same side, with compatible motion findings. A standing-positive/seated-negative pattern can support that interpretation, but it cannot exclude all sacral disease or coexisting dysfunction. These palpatory tests have limited reproducibility. In a study of three trained osteopathy students examining 52 people, agreement ranged from slight to fair. That finding supports caution about certainty; it does not estimate every experienced clinician's performance. [3] [4]

Two rotations, four torsion patterns

In the conventional torsion pattern, the deeper sulcus and posterior/inferior ILA are on opposite sides. The rotation is named opposite the deeper sulcus. The oblique axis is named for its superior end at one side of the sacroiliac region and runs toward the opposite lower side. It is a model for coupled motion, not an anatomical rod through the bone.

Same landmarks, different axis

Deep right sulcus and posterior left ILA

Right-positive seated flexion plus negative spring supports left-on-left.

Left-positive seated flexion plus positive spring supports left-on-right.

The mirror comparison

Deep left sulcus and posterior right ILA

Left-positive seated flexion plus negative spring supports right-on-right.

Right-positive seated flexion plus positive spring supports right-on-left.

Write the name as rotation-on-axis. Matching sides, left-on-left or right-on-right, describe forward torsions. Opposite sides, left-on-right or right-on-left, describe backward torsions. Forward patterns resemble the motion modeled during walking, which explains the historical term physiologic. A restricted forward pattern is still a dysfunction. “Backward” does not prove a traumatic cause, and “forward” does not prove a harmless cause. [1] [2]

Use L5 as a consistency check

In the classic compensated torsion model, L5 rotates opposite the sacrum and sidebends toward the sacral axis. Left-on-left therefore pairs with L5 neutral, rotated right and sidebent left. Right-on-right pairs with L5 neutral, rotated left and sidebent right. These are neutral or Type I relationships.

Left-on-right pairs with non-neutral L5 rotated and sidebent right; right-on-left pairs with non-neutral L5 rotated and sidebent left. These are Type II relationships. The torsion name does not establish whether the non-neutral L5 segment specifically prefers flexion or extension. Test that segment rather than inventing an F or E finding. AACOM also describes maladapted L5 relationships, so an unexpected L5 finding is a reason for further assessment rather than proof the examiner must have palpated the wrong sacrum. [1]

Try an internal consistency check before treatment. Deep right sulcus, posterior left ILA and right-positive seated flexion point toward left-on-left. A clearly positive spring conflicts with that usual pattern. Repeat the contacts and motion tests, assess guarding and the lumbar region, and document uncertainty if the disagreement remains. A confident label built by ignoring one finding is less useful than an accurate description of the conflict.

Same-side findings and symmetric findings

Unilateral patterns combine the base and ILA findings on the affected side. Flexion gives a deep sulcus and posterior/inferior ILA on that side. Extension gives a shallow sulcus and anterior/superior ILA on that side. The seated-flexion side helps distinguish a flexed side from an extended opposite side when only relative landmarks are reported.

Unilateral and bilateral comparisons in the conventional diagnostic model
Pattern	Base and ILA	Motion support
Right unilateral flexion	Right sulcus deep; right ILA posterior/inferior	Right seated flexion positive; spring negative
Left unilateral flexion	Left sulcus deep; left ILA posterior/inferior	Left seated flexion positive; spring negative
Right unilateral extension	Right sulcus shallow; right ILA anterior/superior	Right seated flexion positive; spring positive
Left unilateral extension	Left sulcus shallow; left ILA anterior/superior	Left seated flexion positive; spring positive
Bilateral flexion	Both sulci deep; both ILAs posterior/inferior	No lateralizing seated difference; restricted extension, compliant spring
Bilateral extension	Both sulci shallow; both ILAs anterior/superior	No lateralizing seated difference; reduced anterior spring

Four torsions, four sided unilateral diagnoses and two bilateral diagnoses make ten named patterns. Grouping the right and left unilateral versions together gives eight categories, but those are not eight exhaustive diagnoses. The side must appear in a unilateral diagnosis. [2] [3]

For example, a deep right sulcus and an anterior left ILA become a relatively shallow left sulcus plus anterior left ILA. If seated flexion is positive left and spring is positive, the combined findings support left unilateral extension. Do not name left rotation from a deep right sulcus alone; the opposite-corner torsion pattern has not been established.

Lordosis, apparent leg length, a pelvic shift and difficulty standing upright are context. None is a specific bilateral-sacral test. A cyclist can have a torsion, and a person wearing a lead apron can have a lumbar problem. A symmetric examination with normal motion and no relevant tissue findings may be normal. [3] [4]

Try it here · Checkpoint 2 of 3

Make your prediction before reading the choices. A first attempt is just a starting point.

Case 7

Show answer and explanations

A. Right unilateral flexion (Why this does not fit)
Flexion would produce a deep right sulcus and posterior/inferior right ILA.
B. Right-on-left torsion (Why this does not fit)
A right-on-left torsion would pair the shallow right sulcus with a posterior right ILA, not the anterior ILA reported.
C. Left unilateral extension (Why this does not fit)
The positive seated-flexion side and extension-position landmarks are right-sided.
D. Right unilateral extension (Best answer)
The affected side has a posterior base and anterior/superior ILA with reduced spring.

Takeaway: Shallow base plus anterior/superior ILA on the affected side supports extension.

Case sources: [2] [3]

Use anatomy without turning it into a pain diagnosis

The familiar five-axis teaching scheme includes two oblique axes and three transverse axes. The superior transverse axis is associated with respiratory and craniosacral descriptions, the middle with sacral postural motion, and the inferior with innominate motion relative to the sacrum. These are conceptual reference axes, not five visible hinges. Published diagrams vary in exact segmental placement. The superior axis is often described near posterior S2; an S1 label should not be presented as an uncontested anatomical measurement. Keep the functional distinction and avoid diagnosing from a single drawn line. [1] [8]

In respiratory-assisted teaching, inspiration is associated with sacral extension and expiration with sacral flexion. The terms craniosacral flexion and sacral flexion refer to different models and can describe opposite base directions. State which system you mean. Respiratory observations guide a tolerated technique; they do not prove a mechanism for visceral symptoms. [2]

Several ligaments help you orient the region. The interosseous sacroiliac ligament connects the sacral and iliac tuberosities deep to the posterior joint. The sacrotuberous ligament connects the sacral region to the ischial tuberosity and helps resist nutation. The iliolumbar ligament links the lower lumbar region, especially L5, to the ilium. Their attachments can be learned reliably; which structure is painful cannot be inferred from occupation or a fall alone. [9]

The uterosacral support complex relates the cervix and upper vagina to posterior pelvic tissues. Its posterior attachments are variable and include fascia and coccygeus/sacrospinous regions; it is not simply a rigid cable to sacral bone. An MRI study of asymptomatic volunteers documented this variation; it did not test the cause of pelvic pain. Sacral asymmetry plus dyspareunia does not establish that tension in this complex caused the pain. Gynecologic and other pelvic causes still require assessment. [6] [7]

Before a structural examination dominates the visit, assess severe or changing pain, trauma, cancer history, fever, neurologic loss and new bladder, bowel or saddle sensory symptoms. A normal plain radiograph does not make every painful sacrum safe to manipulate. Persistent focal pain in fragile bone can require further evaluation for an occult fracture. [11] Low-back-pain assessment must consider fracture, infection, malignancy and inflammatory disease where indicated. [5]

Let the diagnosis guide a specific treatment

For commonly taught torsion muscle energy, position the patient on the side of the named axis. Forward torsions commonly use modified Sims positioning with the torso turned toward the table. Backward torsions commonly use lateral recumbency with the torso rotated away from the table. “Face up” does not mean lying flat supine. Localize through the lumbosacral region and the chosen lower-limb lever. Do not prescribe a universal hip angle or mix the top-leg and bottom-leg instructions from different techniques.

In a typical forward setup, a resisted attempt to lift the feet is followed by relaxation and renewed barrier engagement. In a typical backward setup, the supported leg provides a resisted lifting effort while the clinician monitors localization. Both are active techniques. They require comfortable participation, modest effort and reassessment, not maximal contraction. The axis-side rule here belongs to this muscle-energy family, not every possible sacral technique. [3]

For a prone respiratory-assisted flexion pattern, contact at the affected ILA region follows its anterior excursion during inspiration to encourage sacral extension. For an extension pattern, contact at the affected base follows anterior excursion during expiration to encourage sacral flexion. For the described prone bilateral-flexion method, both ILA regions are contacted to encourage anterior and cephalad excursion during inspiration. For bilateral extension, the base is followed anteriorly during expiration. These are respiratory-assisted methods; the active leg effort in torsion muscle energy is a separate procedure. [2] [3]

These distinctions explain the target and the source of effort. Actual execution requires supervised training, informed consent and screening for fracture, unstable injury, infection, local malignancy or other technique-specific risks. A lower-force option still requires a safe target. Reassess the same landmarks and motion tests, symptoms and function after treatment. Do not promise correction of pelvic-organ symptoms from a sacral label.

Check symptoms and safety before assigning a mechanical explanation.
Record both sulci and both ILAs using explicit patient-side labels.
Separate opposite-side, same-side and symmetric patterns.
Use seated flexion for lateralization and spring or sphinx for anterior compliance.
Name rotation-on-axis only when a torsion pattern fits, then check L5.
Resolve discordant findings before choosing a specific technique and reassess afterward.

Try it here · Checkpoint 3 of 3

Make your prediction before reading the choices. A first attempt is just a starting point.

Case 22

Show answer and explanations

A. Posterior ILA excursion to increase nutation (Why this does not fit)
That would reinforce the flexed position rather than encourage extension.
B. Anterior and caudal base excursion (Why this does not fit)
An anterior base target encourages flexion, whereas this flexed pattern needs extension through the ILA contact.
C. Anterior and cephalad ILA excursion (Best answer)
Following the ILA in this direction during inspiration supports sacral extension in the described technique.
D. Caudal ILA excursion while maintaining its posterior position (Why this does not fit)
Caudal and posterior ILA positioning reinforces sacral flexion; the missing direction in this patient is extension.

Takeaway: For respiratory-assisted flexion treatment, the ILA contact encourages extension.

Case sources: [2] [3]

Build and challenge the sacral diagnosis

Case 1

Show answer and explanations

A. Right-on-right torsion (Why this does not fit)
Right-on-right would have a deep left sulcus and left-positive seated flexion, the mirror of these findings.
B. Left-on-left torsion (Best answer)
Opposite-corner landmarks indicate left rotation; right-positive seated flexion indicates a left axis, and compliant spring supports a forward pattern.
C. Left-on-right torsion (Why this does not fit)
It shares the deep-right/posterior-left landmarks but ordinarily has left-positive seated flexion and positive spring.
D. Right unilateral flexion (Why this does not fit)
Right unilateral flexion would pair the deep right sulcus with a posterior right ILA, not a posterior left ILA.

Takeaway: The axis and spring separate torsions with identical static landmarks.

Case sources: [1] [2] [3]

Case 2

Show answer and explanations

A. Left-on-left forward torsion (Why this does not fit)
A deep right sulcus and right-positive seated flexion would support this mirror pattern.
B. Right-on-left backward torsion (Why this does not fit)
The rotation fits, but the left-positive seated flexion and improved symmetry support a right axis and forward pattern.
C. Right-on-right forward torsion (Best answer)
Deep left plus posterior right gives right rotation; left-positive seated flexion gives a right axis, with an improving sphinx response.
D. Left unilateral extension (Why this does not fit)
Left unilateral extension would have a shallow left sulcus and anterior left ILA, rather than the reported torsion geometry.

Takeaway: Right rotation on a right axis is a forward torsion.

Case sources: [1] [2] [3]

Case 3

Show answer and explanations

A. Left-on-left torsion (Why this does not fit)
This shares static landmarks but has the opposite seated-flexion lateralization and usually compliant spring.
B. Right-on-left torsion (Why this does not fit)
That is right rotation, generally producing a deep left sulcus and posterior right ILA.
C. Left unilateral flexion (Why this does not fit)
Left unilateral flexion would put both the deep sulcus and posterior ILA on the left and have negative spring.
D. Left-on-right torsion (Best answer)
The left rotation is on a right axis, inferred from left-positive seated flexion; positive spring supports the backward pattern.

Takeaway: Different rotation and axis sides define a backward torsion.

Case sources: [1] [2] [3]

Case 4

Show answer and explanations

A. Right-on-left torsion (Best answer)
The landmarks indicate right rotation, seated flexion identifies a left axis, and sphinx supports a backward pattern.
B. Right-on-right torsion (Why this does not fit)
The static rotation fits, but this forward pattern would usually have left-positive seated flexion and improving symmetry.
C. Left-on-right torsion (Why this does not fit)
That left-rotation pattern would require a deep right sulcus and posterior left ILA.
D. Right unilateral extension (Why this does not fit)
The posterior/inferior right ILA does not match the anterior/superior right ILA of right unilateral extension.

Takeaway: Use the full pattern instead of choosing from the pain side.

Case sources: [1] [2] [3]

Case 5

Show answer and explanations

A. Left-on-left torsion (Why this does not fit)
That torsion requires a posterior left ILA opposite the deep right sulcus.
B. Right unilateral sacral flexion (Best answer)
Both flexion-position landmarks are on the right, and right-positive seated flexion identifies that side as dysfunctional.
C. Right unilateral sacral extension (Why this does not fit)
Extension on the right would produce a shallow right sulcus and anterior/superior right ILA.
D. Bilateral sacral flexion (Why this does not fit)
The findings are lateralized right rather than symmetrically restricted on both sides.

Takeaway: Same-side deep sulcus and posterior/inferior ILA support unilateral flexion.

Case sources: [2] [3]

Case 6

Show answer and explanations

A. Right-on-right torsion (Why this does not fit)
Right-on-right would pair the deep left sulcus with a posterior right ILA, not a posterior left ILA.
B. Left unilateral extension (Why this does not fit)
A shallow left sulcus and anterior left ILA would support extension; this is the reverse positional pattern.
C. Left unilateral flexion (Best answer)
The deep sulcus and posterior/inferior ILA share the positive seated-flexion side, with compliant spring.
D. Bilateral extension (Why this does not fit)
Bilateral extension has symmetric shallow sulci and reduced anterior spring, neither of which is described.

Takeaway: Use geometry and motion rather than the cycling history.

Case sources: [2] [3]

Case 8

Show answer and explanations

A. Left unilateral extension (Best answer)
Both extension-position landmarks and the positive seated-flexion test identify the left side.
B. Left-on-right torsion (Why this does not fit)
That torsion has posterior/inferior left ILA despite the shallow left base. The ILA here is anterior/superior.
C. Left unilateral flexion (Why this does not fit)
This reverses both the left base and ILA positions and would usually have compliant spring.
D. Right-on-right torsion (Why this does not fit)
The geometry is unilateral, and the reduced spring does not fit a conventional forward torsion.

Takeaway: The ILA distinguishes unilateral extension from a backward torsion with a similar sulcus finding.

Case sources: [2] [3]

Case 9

Show answer and explanations

A. Normal examination because seated flexion is negative (Why this does not fit)
The bilateral positional pattern and reproducible extension restriction are additional findings; a nonlateralizing test does not cancel them.
B. Bilateral sacral flexion (Best answer)
Symmetric flexion-position landmarks with restricted extension and compliant anterior spring support this pattern.
C. Bilateral sacral extension (Why this does not fit)
Extension would have shallow sulci and anterior/superior ILAs, with reduced anterior compliance.
D. Left-on-left torsion (Why this does not fit)
A torsion would require an asymmetric opposite-corner pattern rather than bilateral matching findings.

Takeaway: Symmetry does not exclude a bilateral restriction.

Case sources: [2] [3] [4]

Case 10

Show answer and explanations

A. Bilateral flexion (Why this does not fit)
Bilateral flexion has deep sulci and posterior/inferior ILAs, the opposite positions.
B. Right-on-left torsion (Why this does not fit)
That torsion requires an asymmetric deep-left/posterior-right pattern and a right-positive seated test.
C. Bilateral extension (Best answer)
The symmetric posterior-base/anterior-ILA pattern and reduced spring support bilateral extension.
D. No sacral dysfunction solely because both thumbs rise equally (Why this does not fit)
Equal thumb excursion cannot exclude the described symmetric restriction.

Takeaway: Bilateral extension requires compatible bilateral landmarks and restricted anterior compliance.

Case sources: [2] [3]

Case 11

Show answer and explanations

A. Right-positive seated flexion and negative spring (Why this does not fit)
That pair supports left-on-left, the forward torsion with the same static landmarks.
B. Left-positive seated flexion and negative spring (Why this does not fit)
Left-positive seated flexion suggests the right axis, but negative spring conflicts with the expected backward pattern.
C. Right-positive seated flexion and positive spring (Why this does not fit)
The two tests conflict with a single conventional torsion for the stated left-rotation geometry.
D. Left-positive seated flexion and positive spring (Best answer)
These identify a right axis and a backward pattern, completing left-on-right.

Takeaway: Static left rotation is insufficient to distinguish its two torsions.

Case sources: [1] [2] [3]

Case 13

Show answer and explanations

A. Finalize left-on-left using the landmarks and seated-flexion result (Why this does not fit)
That working pattern conflicts with the repeatedly reduced anterior spring, so it is not fully confirmed.
B. Recheck localization, guarding and lumbar exam before naming it (Best answer)
The static pattern and lateralization suggest left-on-left, while spring conflicts. Reassessment addresses the disagreement.
C. Finalize left-on-right using the landmarks and spring result (Why this does not fit)
That working pattern conflicts with the right-positive seated test; selecting only two findings does not resolve the disagreement.
D. Finalize bilateral extension using the reduced spring (Why this does not fit)
The asymmetric landmarks and lateralizing seated test do not establish a symmetric bilateral pattern.

Takeaway: Conflicting examination findings need reconciliation rather than forced classification.

Case sources: [2] [3] [4]

Case 14

Show answer and explanations

A. A negative seated test excludes any sacral dysfunction from the clinical assessment (Why this does not fit)
The test cannot exclude bilateral restriction, other disease or a coexisting problem.
B. Posterior rotation of the right innominate is established by the pelvic findings (Why this does not fit)
Posterior rotation would reverse the ASIS/PSIS height pattern.
C. Anterior right innominate rotation is supported; assess the remaining findings (Best answer)
The pelvic landmarks and standing test support that interpretation without turning seated flexion into an absolute exclusion test.
D. Left-on-right torsion is established by the height of the right PSIS alone (Why this does not fit)
A resting PSIS height alone does not supply sacral sulcus, ILA or torsion-axis findings.

Takeaway: Innominate findings support a diagnosis without excluding every sacral possibility.

Case sources: [3] [4]

Case 15

Show answer and explanations

A. Bilateral flexion because the findings are symmetric (Why this does not fit)
Symmetry without restricted motion or supportive tissue findings does not establish flexion dysfunction.
B. Bilateral extension because seated flexion is negative (Why this does not fit)
A nonlateralizing test is not a diagnosis, and anterior spring is compliant.
C. A residual torsion established by the previous episode of pain (Why this does not fit)
The history warrants an examination, but no asymmetric torsion pattern or current restriction is demonstrated.
D. No sacral somatic dysfunction is demonstrated by these findings (Best answer)
The examination supplies normal symmetry and motion without evidence of an active restriction.

Takeaway: Normal symmetry and motion should not be relabeled as bilateral disease.

Case sources: [3] [4]

Case 16

Show answer and explanations

A. Neutral, rotated left and sidebent right (Best answer)
L5 rotation opposes the right-rotated sacrum, and its sidebending is toward the right axis.
B. Neutral, rotated right and sidebent left (Why this does not fit)
That reverses both expected relationships for right-on-right.
C. Non-neutral, rotated left and sidebent left (Why this does not fit)
This Type II relationship pairs conventionally with a right-on-left backward torsion.
D. Non-neutral, rotated right and sidebent right (Why this does not fit)
This Type II relationship pairs conventionally with left-on-right, not right-on-right.

Takeaway: In a compensated forward torsion, check opposite L5 rotation and sidebending toward the axis.

Case sources: [1] [2]

Case 17

Show answer and explanations

A. Record flexed, rotated right and sidebent right without further testing (Why this does not fit)
The predicted rotation and sidebending do not establish an untested flexion preference.
B. Expect non-neutral L5 rotated and sidebent right, then test its flexion/extension preference (Best answer)
Opposite rotation and sidebending toward the right axis give the expected relationship; F versus E still requires testing.
C. L5 must rotate left because the sacrum rotates left (Why this does not fit)
The compensated model predicts opposite L5 and sacral rotation.
D. L5 must be neutral and sidebent left (Why this does not fit)
That relationship would be associated with a forward left-on-left pattern, not the stated backward torsion.

Takeaway: Do not invent an F or E finding from a torsion name.

Case sources: [1] [8]

Case 18

Show answer and explanations

A. A right-positive seated flexion test (Why this does not fit)
The side with greater superior excursion is left, not right.
B. A complete left-on-right torsion diagnosis (Why this does not fit)
The test does not supply sulcus depth, ILA position or anterior compliance needed to distinguish categories.
C. A left-positive seated flexion test (Best answer)
This names the observed lateralization. A torsion axis can be inferred only after the remaining pattern supports a torsion.
D. A left anterior innominate rotation (Why this does not fit)
A complete innominate diagnosis requires pelvic landmarks and motion assessment, not this seated observation alone.

Takeaway: Name the test result before assigning a full diagnosis.

Case sources: [2] [3]

Case 19

Show answer and explanations

A. Negative spring, supporting anterior base motion (Why this does not fit)
Reduced anterior yield is conventionally a positive spring result, not a compliant negative result.
B. Positive spring, sufficient to name left-on-right torsion (Why this does not fit)
The positive spring is correctly identified, but landmarks and lateralizing findings are still needed to name this specific torsion.
C. Positive spring, sufficient to name bilateral extension (Why this does not fit)
The test does not establish a symmetric bilateral pattern without compatible positional and other motion findings.
D. Positive spring, supporting restricted anterior base motion (Best answer)
This accurately states the observation and its mechanical meaning without inventing a sided diagnosis.

Takeaway: Positive spring identifies reduced anterior compliance, not a unique torsion.

Case sources: [2] [3]

Case 20

Show answer and explanations

A. The landmark response supports an anterior pattern, while the extension pain needs its own assessment (Best answer)
The sacral response and pain report are different observations; pain alone does not reverse the measured improvement in symmetry.
B. Classify a posterior sacral pattern from the increased extension pain (Why this does not fit)
Pain alone is not the positional response being assessed, and the more symmetric landmarks and compliant spring favor an anterior pattern.
C. Discard the improved symmetry because pain persists (Why this does not fit)
The positional response remains useful even though the lumbar pain needs separate assessment.
D. Diagnose bilateral extension from the painful lumbar extension (Why this does not fit)
Bilateral extension needs compatible symmetric positional findings and reduced anterior spring; pain alone supplies neither.

Takeaway: Describe the landmark response separately from pain provoked by lumbar extension.

Case sources: [2] [3] [5]

Case 21

Show answer and explanations

A. Use an oblique reference axis named for the side of the innominate (Why this does not fit)
The oblique axes belong to the conventional sacral torsion model, not the anterior/posterior innominate rotation model.
B. Innominate motion on the sacrum uses the inferior transverse axis (Best answer)
The middle reference axis concerns sacral postural motion; the inferior axis is the conventional iliosacral reference.
C. Use the superior transverse reference axis (Why this does not fit)
The superior transverse axis is the respiratory reference in this scheme; the inferior is the innominate reference.
D. Retain the middle transverse axis as the innominate reference (Why this does not fit)
The middle axis describes sacral postural motion in the conventional glossary scheme.

Takeaway: Separate sacral-on-innominate from innominate-on-sacral motion.

Case sources: [1] [8]

Case 23

Show answer and explanations

A. Inspiration with anterior pressure at the right ILA (Why this does not fit)
That describes the flexion-pattern extension target, not an extended base needing anterior excursion.
B. Expiration with posterior pressure on the sacral base (Why this does not fit)
Posterior base pressure would reinforce extension rather than encourage nutation.
C. Inspiration while maintaining the base in its posterior preference (Why this does not fit)
This follows the extension preference rather than encouraging the restricted anterior base excursion in the specified direct method.
D. Expiration while following the right base anteriorly (Best answer)
The goal is sacral flexion, with anterior base excursion during expiration in this respiratory-assisted method.

Takeaway: An extension pattern needs anterior base excursion; technique and respiratory cue must agree.

Case sources: [2]

Case 24

Show answer and explanations

A. Left side down with torso rotated toward the table (Best answer)
The named axis is left; the common forward method uses axis-side-down modified Sims positioning.
B. Right side down with torso rotated toward the table (Why this does not fit)
This puts the opposite side of the named axis on the table.
C. Left side down with torso rotated away from the table (Why this does not fit)
That torso direction is characteristic of the common backward-torsion family rather than this forward setup.
D. Right side down with torso rotated away from the table (Why this does not fit)
This corresponds to a commonly taught right-axis backward setup, not the selected left-on-left forward method.

Takeaway: For the specified forward muscle-energy family, identify the axis before positioning.

Case sources: [3]

Case 25

Show answer and explanations

A. Left side down with the torso rotated away from the table (Why this does not fit)
The described muscle-energy family places the named axis down; this torsion has a right axis.
B. Right side down with the torso rotated away from the table and the barrier localized (Best answer)
That matches the common backward-torsion family on the named right axis without assuming a universal hip angle.
C. Right side down with the torso turned toward the table as in forward Sims positioning (Why this does not fit)
The side matches, but the torso direction belongs to the commonly taught forward setup.
D. Left side down with the torso rotated toward the table (Why this does not fit)
This combines the wrong axis side with a forward rather than backward torso position.

Takeaway: Do not confuse torso rotation with the patient's entire recumbent position.

Case sources: [3]

Case 26

Show answer and explanations

A. Increase the counterforce while keeping the same painful patient effort (Why this does not fit)
A stronger counterforce does not correct excessive, painful trunk recruitment. Stop and reassess localization first.
B. Shorten each contraction but continue the same effort and position (Why this does not fit)
Shorter duration does not make an already painful, poorly localized effort appropriate.
C. Stop the painful effort, reassess positioning and use a smaller localized effort only if tolerated (Best answer)
Muscle energy depends on controlled participation; pain and whole-trunk recruitment call for reassessment.
D. Switch immediately to a passive local technique without reassessing the pain (Why this does not fit)
New or increasing pain requires reassessment before selecting another procedure.

Takeaway: Patient effort should preserve localization and comfort.

Case sources: [3]

Case 27

Show answer and explanations

A. Anterior pressure at the base to increase sacral flexion (Why this does not fit)
The sacrum already favors flexion; this would not target the restricted extension.
B. A unilateral base contact selected only by the pain side (Why this does not fit)
The documented restriction is bilateral, so pain side alone does not define the contact pattern.
C. Bilateral ILA contacts following posterior excursion during expiration (Why this does not fit)
Following posterior ILA excursion encourages the existing flexion preference rather than the restricted extension.
D. A central or bilateral ILA/apex-region contact encouraging anterior ILA excursion during inspiration (Best answer)
The contact below the transverse reference region encourages sacral extension in the specified flexion method.

Takeaway: Bilateral methods use the same target distinction without inventing a sided torsion.

Case sources: [2]

Case 28

Show answer and explanations

A. Interosseous sacroiliac ligament (Best answer)
Its deep sacral-to-iliac tuberosity relationship distinguishes it from the other listed structures; location alone does not prove it is painful.
B. Sacrotuberous ligament (Why this does not fit)
This spans toward the ischial tuberosity rather than linking the two posterior tuberosities directly.
C. Iliolumbar ligament (Why this does not fit)
Its defining relation is from the lower lumbar region, especially L5, toward the ilium.
D. Long posterior sacroiliac ligament (Why this does not fit)
This is a more superficial posterior supporting ligament. The stem identifies the deeper interosseous connection between the tuberosities.

Takeaway: Learn the ligament attachment without inferring a pain generator.

Case sources: [9]

Case 29

Show answer and explanations

A. Treat the sacral asymmetry first and defer pelvic evaluation unless pain persists (Why this does not fit)
The chronic dyspareunia and menstrual association warrant their own assessment without waiting for a structural treatment trial.
B. Evaluate gynecologic and other pelvic causes while assessing any musculoskeletal contribution (Best answer)
The symptoms require their own differential; sacral asymmetry can be considered without displacing that assessment.
C. Limit the initial assessment to infection testing (Why this does not fit)
Infectious causes are only part of the differential; the menstrual association also warrants consideration of noninfectious gynecologic causes.
D. Attribute the symptoms to endometriosis from the menstrual association alone (Why this does not fit)
Endometriosis is a reasonable consideration, but this history alone does not establish the cause or eliminate other contributors.

Takeaway: Pelvic symptoms require cause-directed assessment, even when OMM findings coexist.

Case sources: [6] [7]

Case 30

Show answer and explanations

A. They arise predominantly from the uterine fundus and attach to the posterior sacrum (Why this does not fit)
The MRI study describes cervical and upper-vaginal origins, not a predominantly fundal origin.
B. They extend from the cervix and upper vagina directly to sacral bone in most subjects (Why this does not fit)
Direct sacral insertion was a minority finding in the asymptomatic MRI study; posterior soft-tissue attachments predominated.
C. Cervix and upper vagina link to variable posterior pelvic tissues, including fascia (Best answer)
Imaging and anatomical work show variable posterior attachments rather than one uniform rigid sacral cable.
D. They arise from the cervix and insert predominantly on the ischial tuberosity (Why this does not fit)
The study describes variable posterior pelvic tissues, not a predominant ischial-tuberosity insertion.

Takeaway: An anatomical relationship is not a complete causal explanation.

Case sources: [6]

Case 31

Show answer and explanations

A. Arrange outpatient lumbar MRI within the next week (Why this does not fit)
New bladder dysfunction and perineal numbness with radiating back pain require immediate assessment, not delayed outpatient imaging.
B. Obtain a postvoid residual and refer only if it is markedly increased (Why this does not fit)
A bladder measurement may contribute to evaluation but should not postpone immediate referral or negate the concerning symptom combination.
C. Arrange routine review after a trial of home stretching (Why this does not fit)
These new neurologic symptoms require urgent assessment, not a delayed trial.
D. Arrange emergency assessment for possible cauda equina compression (Best answer)
Back pain with new bladder dysfunction and saddle sensory change requires urgent evaluation regardless of sacral asymmetry.

Takeaway: Neurologic red flags outrank a somatic dysfunction label.

Case sources: [5] [10]

Case 32

Show answer and explanations

A. Reassess for an occult injury and pursue clinically indicated further evaluation (Best answer)
Persistent severe post-traumatic pain in fragile bone is not cleared by a normal plain film; local manipulation should await appropriate assessment.
B. Accept the plain film and begin gentle local treatment with weight bearing as tolerated (Why this does not fit)
Severe focal pain and inability to bear weight in fragile bone require further injury assessment despite a negative plain film.
C. Begin low-effort muscle energy and investigate further if it fails (Why this does not fit)
Even low-effort treatment loads the potentially injured sacrum and should await assessment.
D. Manage as an uncomplicated contusion and review routinely in two weeks (Why this does not fit)
Marked functional limitation and persistent focal pain make delayed routine review insufficient before further evaluation.

Takeaway: A normal radiograph is not automatic clearance for manipulation.

Case sources: [3] [5] [11]

Sources

AACOM. Glossary of Osteopathic Terminology, third edition (2017)
Primary professional terminology, ILA definition, compensated and maladapted L5 relationships, torsion naming and the three transverse reference axes (printed pages 53-59). The 2017 AACOM publication was read in full relevant PDF pages through an educational mirror; it is not described as the newest edition.
Greg Thompson. Sacral Instant Diagnosis & Treatment with Ligamentous Articular Strain (LAS). American Academy of Osteopathy teaching slides
Official osteopathic teaching slides on landmarks, ten diagnoses, seated flexion, spring/sphinx, respiratory-assist contacts and phase. Obvious slide typos are not adopted.
McParland, Sina and DeLuca. Osteopathic Manipulative Treatment, Muscle Energy Procedure, Sacral Dysfunctions (2024-03-01)
Clinical teaching cross-check of negative seated flexion in bilateral dysfunction, diagnostic patterns and specific muscle-energy setups. Anatomy errors and conflicting bilateral-extension respiratory cue are not adopted; AAO respiratory-assist description supplies that phase.
Consorti et al. Interrater Reliability of Osteopathic Sacral Palpatory Diagnostic Tests Among Osteopathy Students (2018)
Primary study of 52 subjects and three student raters; slight-to-fair agreement and limits on diagnostic certainty.
NICE NG59. Low back pain and sciatica in over 16s, recommendations
Official assessment guidance to consider cancer, infection, trauma and inflammatory causes; imaging should follow clinical indications.
Umek et al. Quantitative Analysis of Uterosacral Ligament Origin and Insertion Points by Magnetic Resonance Imaging (2004-03)
Primary MRI anatomy study in asymptomatic volunteers: variable cervical/upper-vaginal origins and posterior attachments. This was not a study of pelvic-pain causation or OMT effectiveness.
ACOG. Chronic Pelvic Pain (2025-10)
Official clinical guidance on pelvic-pain differential and need for cause-directed evaluation; no causal diagnosis from sacral asymmetry. Page reports last updated October 2025. Official indexed content was readable; direct automated retrieval returned HTTP 402.
Kenneth E. Nelson. The sacrum; A bone of contention. AAO Journal 1997;7(4):17-24 (1997)
Professional discussion of conceptual, nonfixed sacral axes and non-neutral L5 mechanics. The downloaded AAO PDF article was read directly, especially printed pages 21-23; the glossary provides the formal transverse-axis definitions.
Vleeming et al. The sacroiliac joint, an overview of its anatomy, function and potential clinical implications (2012)
Anatomical review used as a secondary cross-check of interosseous sacroiliac, sacrotuberous and iliolumbar attachments. Relevant full-article passages were read through the live index; direct PMC retrieval encountered a browser challenge. It does not establish a ligament pain diagnosis from posture alone.
NICE NG127. Suspected neurological conditions, recommendation 1.7.3
Immediate referral for assessment of cauda equina syndrome with severe radiating low back pain and new bladder, bowel, sexual or perineal sensory disturbance.
American College of Radiology. ACR Appropriateness Criteria, Stress (Fatigue/Insufficiency) Fracture Including Sacrum, 2024 revision (2024)
Official 2024 criteria for adult suspected stress or insufficiency fracture, including the sacrum. For negative or indeterminate radiographs, MRI without contrast is usually appropriate in the relevant variants. Supports further injury assessment in the fragile-bone case; this is not a universal acute-trauma imaging protocol. Relevant official indexed variant tables were read; direct retrieval returned HTTP 403.

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