THE BIG PICTURE
Beyond Rotations
The innominate moves in more ways than anterior and posterior rotation. Tap each card to see what makes it different.
You already know the innominate can rotate: anterior rotation (ASIS drops inferior, PSIS goes superior) and posterior rotation (ASIS goes superior, PSIS drops inferior). But the SI joint allows three other types of motion that the boards test aggressively.
Shear (Upslip / Downslip)
The innominate slides straight UP or DOWN along the SI joint. ASIS and PSIS move in the same direction.
Superior shear (upslip): The whole innominate shifts superiorly. Both ASIS and PSIS are higher on that side; the pubic ramus and ischial tuberosity also travel superiorly; medial malleolus is superior (leg appears shorter). Etiology: trauma, classically a fall onto one buttock.
Inferior shear (downslip): The whole innominate shifts inferiorly. Both landmarks (and the pubic ramus) are lower on that side. Etiology: trauma. Less common on boards.
Key rule: In rotation, ASIS and PSIS go OPPOSITE. In shear, they go TOGETHER.
Inferior shear (downslip): The whole innominate shifts inferiorly. Both landmarks (and the pubic ramus) are lower on that side. Etiology: trauma. Less common on boards.
Key rule: In rotation, ASIS and PSIS go OPPOSITE. In shear, they go TOGETHER.
Flare (Inflare / Outflare)
The innominate rotates in the transverse plane, moving the ASIS medially or laterally.
Inflare: ASIS moves medially (toward midline). That side of the pelvis looks narrower when measured ASIS to ASIS. Transverse plane inward rotation.
Outflare: ASIS moves laterally (away from midline). That side looks wider. Transverse plane outward rotation.
Key rule: Flares are about ASIS position in the transverse plane. Is it closer to midline (inflare) or farther from midline (outflare)?
Outflare: ASIS moves laterally (away from midline). That side looks wider. Transverse plane outward rotation.
Key rule: Flares are about ASIS position in the transverse plane. Is it closer to midline (inflare) or farther from midline (outflare)?
Pubic Shear
The pubic tubercle on one side shifts superiorly or inferiorly relative to the other side at the pubic symphysis.
Superior pubic shear: Pubic tubercle palpates higher on the affected side. Causes: trauma, tight rectus abdominis, pregnancy-related ligament laxity.
Inferior pubic shear: Pubic tubercle palpates lower on the affected side. Causes: trauma, tight adductors, pregnancy.
Key rule: Pubic shears are translatory dysfunctions at the symphysis. Diagnose them by palpating pubic tubercle height directly, not by inferring from innominate rotation.
Inferior pubic shear: Pubic tubercle palpates lower on the affected side. Causes: trauma, tight adductors, pregnancy.
Key rule: Pubic shears are translatory dysfunctions at the symphysis. Diagnose them by palpating pubic tubercle height directly, not by inferring from innominate rotation.
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The board distinction that matters most: In rotation, ASIS and PSIS move in opposite directions. In shear, they move in the same direction. If you remember nothing else from this page, remember that.
VERTICAL SLIDE
Superior & Inferior Shear
The innominate slides up or down. Both landmarks travel together.
Superior Shear (Upslip)
The innominate slides superiorly on the sacrum
| Finding | Detail | Why |
|---|---|---|
| ASIS | Superior on affected side | Whole innominate slid upward |
| PSIS | Superior on affected side | Moves with ASIS because the bone moved as a unit |
| Pubic ramus | Superior on affected side | Travels with the rest of the innominate |
| Ischial tuberosity | Superior on affected side | Travels with the rest of the innominate |
| Medial malleolus | Superior (shorter leg) on affected side | Acetabulum moved up, pulling the femoral head superiorly |
| Standing flex / ASIS compression | Positive on affected side | Indicates ipsilateral innominate dysfunction |
| Etiology | Trauma (e.g., fall on one buttock) | Force drives innominate superiorly along the SI joint |
| Muscle Energy | Supine; abduct affected leg 10 to 15 degrees and internally rotate. Patient lifts hip against equal resistance 3 to 5 sec, relax, re-engage, repeat 3 to 5x. | Engages the restrictive barrier and recruits muscles to reset the innominate |
| HVLA option | Supine; apply long-axis traction on the affected leg while the patient coughs | Sudden cough adds momentum to the traction force |
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ASIS and PSIS both go UP. That's the signature. In anterior rotation, ASIS goes down while PSIS goes up. In superior shear, they both go up together because the entire bone shifted as a unit, not rotated.
Inferior Shear (Downslip)
The innominate slides inferiorly on the sacrum
| Finding | Detail | Why |
|---|---|---|
| ASIS | Inferior on affected side | Whole innominate slid downward |
| PSIS | Inferior on affected side | Moves with ASIS as a unit |
| Pubic ramus | Inferior on affected side | Travels with the rest of the innominate |
| Standing flex / ASIS compression | Positive on affected side | Indicates ipsilateral innominate dysfunction |
| Etiology | Trauma | Force drives the innominate inferiorly along the SI joint |
| Muscle Energy | Prone with affected hip OFF the side of the table. Flex and abduct the hip; place a hand on the ipsilateral ischial tuberosity and apply a superior plus lateral force. Patient inhales and tries to straighten the leg against resistance, then exhales and relaxes. Re-engage and repeat. | Combined operator force and patient effort lift the innominate back up |
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Inferior shear is less commonly tested than superior shear. Same logic in reverse: both ASIS and PSIS drop together, and the pubic ramus drops with them. Treatment is prone Muscle Energy with the hip off the table, not traction.
Shear vs Rotation: The Key Distinction
This is the board distinction that separates a correct answer from a trap
Board Trap: Don't Confuse Superior Shear with Posterior Rotation
In posterior rotation, ASIS goes superior but PSIS goes inferior. In superior shear, BOTH go superior. The exam will give you a stem where both landmarks are higher on one side and see if you call it a rotation. Check both landmarks. If they went the same way, it's a shear. If they went opposite ways, it's a rotation. Period.
TRANSVERSE PLANE
Inflare & Outflare
The innominate rotates inward or outward in the transverse plane, changing the distance between the ASIS and midline
Flares are about the ASIS moving medially or laterally in the transverse plane. You diagnose them by comparing the distance from each ASIS to the umbilicus (midline). If one ASIS is closer to midline, that's an inflare. If it's farther from midline, that's an outflare.
Both ASIS equidistant from midline: normal alignment
Inflare
- ASIS moves medially (toward midline)
- ASIS-to-umbilicus distance is shorter on that side
- Standing flex / ASIS compression positive on affected side
- Muscle Energy: Supine, physician on the same side. Flex the hip and knee; place the ipsilateral ankle across the opposite knee (figure-4). Stabilize the contralateral ASIS. Abduct and externally rotate the hip to engage the barrier. Patient adducts and internally rotates against equal resistance for 3 to 5 sec, relax 1 to 2 sec, re-engage, repeat 3 to 5x.
Outflare
- ASIS moves laterally (away from midline)
- ASIS-to-umbilicus distance is longer on that side
- Standing flex / ASIS compression positive on affected side
- Muscle Energy: Supine, physician on the same side. Flex the hip and knee; place the ankle across the opposite knee (figure-4). Hook fingers medial to the ipsilateral PSIS and further flex the knee. Adduct and internally rotate the hip to engage the barrier. Patient abducts and externally rotates against equal resistance for 3 to 5 sec, relax, re-engage, repeat 3 to 5x.
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Memory trick: INflare = ASIS moves IN (toward midline). OUTflare = ASIS moves OUT (away from midline). The name tells you exactly which direction the ASIS went.
AT THE SYMPHYSIS
Pubic Shears
The pubic tubercle shifts up or down relative to the other side at the symphysis
The pubic symphysis is the cartilaginous joint where the two innominates meet in the front. A pubic shear is a translatory dysfunction at that joint: one pubic tubercle palpates higher or lower than the other. Diagnose by palpating the two pubic tubercles directly with the patient supine. The dysfunction is named for the side and the direction the tubercle moved.
Superior Pubic Shear
Pubic tubercle palpates higher on the affected side
Findings & Etiology
- Pubic tubercle palpates higher on the affected side
- Often tender at the symphysis on that side
- Causes: trauma, tight rectus abdominis, pregnancy-related ligament laxity
Muscle Energy Treatment
- Position: supine with knees flexed at 90 degrees
- Step 1 (knees closed): patient abducts knees against the operator's resistance for 3 to 5 sec, then relaxes
- Step 2 (knees open): patient adducts knees against operator's resistance for 3 to 5 sec, then relaxes; gradually open the knees wider with each repetition
- Reassess after 3 to 5 cycles
Inferior Pubic Shear
Pubic tubercle palpates lower on the affected side
Findings & Etiology
- Pubic tubercle palpates lower on the affected side
- Often tender at the symphysis on that side
- Causes: trauma, tight adductors, pregnancy
Muscle Energy Treatment
- Position: supine; one hand stabilizes the ipsilateral ASIS
- Flex and abduct the patient's hip; place the other hand on the ipsilateral ischial tuberosity
- Posteriorly rotate the hip with a superior plus medial force while maintaining contact on the ASIS, ischial tuberosity, and knee
- Patient straightens the leg against equal resistance, then relaxes; re-engage and repeat
How To Diagnose A Pubic Shear
Palpate the two tubercles directly. Don't infer from rotation.
| Step | Action | What you are looking for |
|---|---|---|
| 1. Position | Patient supine, knees extended | A neutral pelvis to compare both sides |
| 2. Palpate | Place thumbs on each pubic tubercle just lateral to the midline | Compare superior to inferior position of left vs right |
| 3. Name | The side and the direction the tubercle moved | Higher tubercle = superior pubic shear on that side. Lower tubercle = inferior pubic shear on that side. |
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Pubic shear vs innominate rotation: a pubic shear is a separate dysfunction at the pubic symphysis. It is diagnosed by direct tubercle palpation, not by inferring from ASIS or PSIS rotation findings. Treat it on its own with the appropriate Muscle Energy protocol.
Board Trap: Match The Protocol To The Direction
Superior pubic shear is treated supine with the two-step adductor / abductor Muscle Energy sequence at the knees. Inferior pubic shear is treated supine with hip flexion and abduction, hand on the ischial tuberosity, while the patient straightens the leg against resistance. Don't swap the two protocols.
THE ALGORITHM
Diagnostic Decision Tree
Tap through the flowchart to diagnose any innominate dysfunction
Step 1
Standing flexion test positive?
→
YES on one side: innominate dysfunction on that side. Proceed to Step 2.
→
NO: Consider sacral dysfunction (seated flexion test) or no SI dysfunction present.
STOP
↓
Step 2
Compare ASIS and PSIS positions. Do they go in OPPOSITE directions?
→
OPPOSITE (ASIS inferior + PSIS superior, or vice versa)
ROTATION
→
SAME direction (both superior or both inferior)
SHEAR
↓
Step 3 (if ROTATION)
ASIS is inferior on the affected side?
→
YES (ASIS inferior, PSIS superior)
ANTERIOR ROTATION
→
NO (ASIS superior, PSIS inferior)
POSTERIOR ROTATION
↓
Step 3 (if SHEAR)
Both landmarks are superior or inferior on the affected side?
→
BOTH SUPERIOR (upslip). Leg shorter. Treat with traction.
SUPERIOR SHEAR
→
BOTH INFERIOR (downslip). Leg longer.
INFERIOR SHEAR
↓
Step 4
ASIS shifted medially or laterally? (Measure ASIS-to-umbilicus distance)
→
ASIS closer to midline (distance shorter)
INFLARE
→
ASIS farther from midline (distance longer)
OUTFLARE
↓
Step 5
Palpate the pubic tubercles. Asymmetry in height?
→
Tubercle higher on affected side (palpated directly, supine)
SUPERIOR PUBIC SHEAR
→
Tubercle lower on affected side (palpated directly, supine)
INFERIOR PUBIC SHEAR
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The order matters: Standing flexion test first (which side?). Then ASIS/PSIS comparison (rotation vs shear?). Then ASIS medial/lateral position (flare?). Then pubic symphysis (pubic shear?). Follow this sequence and you will always get the right diagnosis.
THE LINEUP
Innominate Dysfunctions
Tap to flip.
Anterior Innominate Rotation
ASIS inferior, PSIS superior
Anterior Rotation
- ASIS: lower and anterior on affected side
- PSIS: higher and posterior on affected side
- Pubic ramus: inferior on affected side
- Opposite directions: ASIS and PSIS move opposite = rotation
- Rx: MET supine, hip off the table (hip extension barrier)
- Board pearl: Tight hip flexors pull the innominate into anterior rotation
Posterior Innominate Rotation
ASIS superior, PSIS inferior
Posterior Rotation
- ASIS: higher and posterior on affected side
- PSIS: lower and anterior on affected side
- Pubic ramus: superior on affected side
- Opposite directions: ASIS and PSIS move opposite = rotation
- Rx: MET prone, leg hanging off table (hip flexion barrier)
Superior Innominate Shear
Upslip: both landmarks superior
Superior Shear (Upslip)
- ASIS: superior on affected side
- PSIS: also superior on affected side (same direction = shear)
- Pubic ramus: superior; ischial tuberosity superior
- Leg: shorter on affected side (medial malleolus superior)
- Mechanism: fall onto buttock (force drives ilium up)
- Rx: MET supine with long-axis leg traction
Inferior Innominate Shear
Downslip: both landmarks inferior
Inferior Shear (Downslip)
- ASIS: inferior on affected side
- PSIS: also inferior on affected side
- Pubic ramus: inferior on affected side
- Leg: longer on affected side
- Rx: MET prone, hip off table, superior and lateral force on ischial tuberosity
Innominate Outflare
ASIS widens laterally
Outflare
- ASIS: moves laterally (farther from midline)
- ASIS-to-umbilicus distance: longer on affected side
- Pubic bone: moves lateral; pelvic diameter widens
- Rx: MET supine, abduct and externally rotate hip to barrier, patient adducts and internally rotates against resistance
Innominate Inflare
ASIS narrows medially
Inflare
- ASIS: moves medially (closer to midline)
- ASIS-to-umbilicus distance: shorter on affected side
- Pubic bone: moves medial; pelvic diameter narrows
- Rx: MET supine, internally rotate and adduct hip to barrier, patient abducts and externally rotates against resistance
VISUAL REFERENCE
Pelvis Anatomy Reference
Swipe to browse. Wikimedia Commons.
THE ALGORITHM
Decision Tree: Treating Innominate Shear and Flare SD
Tap through to select the correct treatment for each innominate dysfunction type.
Type of innominate dysfunction?
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After every treatment: recheck ASIS symmetry, PSIS symmetry, pubic ramus height, and spring test. If landmarks have not corrected, re-examine before repeating the technique.
PROVE IT
Clinical Vignettes
Five patients. Each one is testing whether you know shears from rotations from flares. Don't get tricked.