Standing vs Seated Test
Standing = Innominate/Leg; Seated = Sacral dysfunction
Spring / Sphinx Test
Poor spring / Asymmetry worsens = Backward Torsion (non-neutral)
L5-Sacrum Rule I
L5 rotation is OPPOSITE to sacral rotation
L5-Sacrum Rule II
L5 sidebending is on the SAME SIDE as the sacral oblique axis
The Step-by-Step Pelvic Diagnostic Sequence
To solve any COMLEX sacral or innominate question, execute this exact algorithm:
Step 1: Standing Flexion Test
Differentiates iliosacral (innominate) from sacroiliac (sacral) etiology. Positive on the side where the PSIS moves superiorly first. If standing is positive and seated is negative: Innominate dysfunction.
Step 2: Seated Flexion Test
Eliminates lower extremity mechanics. Positive on the side where the PSIS moves superiorly first. Names the dysfunctional side of the sacrum.
Step 3: Spring Test / Sphinx Test
Differentiates forward (physiologic/neutral) from backward (non-neutral) torsions. Normal spring / asymmetry improves in extension = Forward torsion (L on L, R on R). Poor spring / hard end-feel / asymmetry worsens in extension = Backward torsion (L on R, R on L).
Master Sacral Torsion Comparison Matrix
Every sacral torsion question hinges on matching the seated flexion test, deep sulcus, posterior ILA, and spring test:
| Finding / Landmark | L on L Torsion | R on R Torsion | L on R Torsion | R on L Torsion |
|---|---|---|---|---|
| Seated Flexion Test | Right positive | Left positive | Left positive | Right positive |
| Oblique Axis | Left axis | Right axis | Right axis | Left axis |
| Deep Sacral Sulcus | Right deep | Left deep | Right deep | Left deep |
| Posterior/Inferior ILA | Left posterior | Right posterior | Left posterior | Right posterior |
| Spring Test | Negative (normal spring) | Negative (normal spring) | Positive (rigid / no spring) | Positive (rigid / no spring) |
| Sphinx Test | Asymmetry improves | Asymmetry improves | Asymmetry worsens | Asymmetry worsens |
| Corresponding L5 | L5 N SLRR | L5 N SRRL | L5 F/E SRRR | L5 F/E SLRL |
Innominate Rotations & Shears
Innominates rotate around the inferior transverse axis of the sacrum:
Anterior Innominate Rotation
ASIS inferior, PSIS superior on the side of the positive standing flexion test. Associated with tight quadriceps / rectus femoris. Treated with muscle energy activating the hamstrings.
Posterior Innominate Rotation
ASIS superior, PSIS inferior on the side of the positive standing flexion test. Associated with tight hamstrings / gluteus maximus. Treated with muscle energy activating rectus femoris.
Superior Innominate Shear (Upslip)
ASIS and PSIS both superior, pubic tubercle superior on the side of the positive standing flexion test. Commonly caused by stepping into an unexpected hole or falling on an ischial tuberosity.
COMLEX / OMM Integration
NBOME High-Yield Correlate
The Three Transverse Axes of the Sacrum
- Superior Transverse Axis (S2 level): Respiratory and Craniosacral motion. During inhalation, the sacral base moves posterior (cranial extension / sacral counternutation).
- Middle Transverse Axis: Postural motion. Forward and backward bending in the sagittal plane.
- Inferior Transverse Axis: Dynamic / Iliosacral motion. The axis upon which the innominates rotate during ambulation.
- Middle Transverse Axis: Postural motion. Forward and backward bending in the sagittal plane.
- Inferior Transverse Axis: Dynamic / Iliosacral motion. The axis upon which the innominates rotate during ambulation.
Board Traps & Common Distractors
- Trap: Thinking seated flexion test is on the side of the axis. The seated flexion test is ALWAYS opposite to the oblique axis in forward torsions, and on the same side in backward torsions!
- Trap: Forgetting the L5 rules. If sacrum is rotated Left, L5 MUST be rotated Right. If oblique axis is Right, L5 MUST be sidebent Right.