Skip to content

Diagnosing sacral somatic dysfunction

Notes

Notes

Sacrum

Diagnosing sacral somatic dysfunction

Steps of diagnosing sacral somatic dysfunction

Figure 1. Effects of sacral extension and flexion on the lumbar spine.

Seated flexion test

With the patient seated, place your thumbs inferior to the PSISs and instruct the patient to bend forward at the hips. Follow the motion of the PSISs with your thumbs. If the PSISs do not move symmetrically, this indicates a positive test. The PSIS that moves farthest (most superior) at the end of range of motion determines the dysfunctional side.

Figure 2. Seated flexion test with a positive result on the left: the left PSIS moved upward relative to the right during seated flexion.

Sacral sulci

With the patient prone, assess the sacral sulci (bases), just medial to the PSIS. The sacral sulcus is “deep” if it is closer to the table (feels more anterior) and “shallow” if it is farther from the table (feels more posterior).

Inferolateral angles (ILAs)

With the patient prone, assess the ILAs, which are at the inferior portion of the sacrum just superior to the coccyx. Next, assess which ILA is more inferior relative to the opposite ILA. The inferior side will also be the posterior one.

Sacral spring test

With the patient prone, apply posterior to anterior pressure (“spring”) onto the sacral base. A lack of spring indicates a bilateral or unilateral sacral extension, or posterior sacral torsion. Normal spring indicates a bilateral or unilateral sacral flexion, or anterior sacral torsion.

Sphinx test

With the patient prone, monitor the sacral sulci. Instruct the patient to move into the sphinx position, which involves having the patient lie prone and prop themselves up on their elbows to extend the lumbar spine and sacrum. If the test is negative (improved symmetry of the bases), this indicates a sacral flexion dysfunction or an anterior sacral torsion. If the test is positive (worsened asymmetry of the bases), this indicates a sacral extension dysfunction or a posterior sacral torsion.

Sacral shears encompass bilateral and unilateral flexion and extension dysfunctions of the sacrum. With unilateral flexion and extension dysfunctions, the deep sacral sulcus and posterior / inferior ILA will be on the same side. The side of the positive seated flexion test identifies the dysfunctional side.

Sacral torsions encompass anterior (L on L / R on R) or posterior (L on R / R on L) torsion dysfunctions of the sacrum. With these diagnoses, the deep sacral sulcus and posterior / inferior ILA will be on the opposite side. The oblique axis will occur on the side opposite of the positive seated flexion test.

L5 will rotate opposite to the direction of sacrum rotation. L5 will side bend to the same side of the oblique axis.
DIAGNOSING SACRAL SOMATIC DYSFUNCTION
DIAGNOSISSEATED FLEXION TESTSACRAL SULCUS (BASE)INFERO-LATERAL ANGLESSPRING/ SPHINX TESTL5
Bilateral sacral flexion
-Deep b/l
Posterior and inferior b/l
-N/A
Bilateral sacral extension
-Shallow b/l
Anterior and superior b/l
+N/A
R unilateral flexion
+ on R
Deep on R
Posterior and inferior on R
-N/A
L unilateral flexion
+ on L
Deep on L
Posterior and inferior on L
-N/A
R unilateral extension
+ on R
Shallow on R
Anterior and superior on R
+N/A
L unilateral extension
+ on L
Shallow on L
Anterior and superior on L
+N/A
L rotation on L oblique axis (L/L)
+ on R
Deep on R
Posterior and inferior on L
-N SL RR
R rotation on R oblique axis (R/R)
+ on L
Deep on L
Posterior and inferior on R
-N SR RL
L rotation on R oblique axis (L/R)
+ on L
Deep on R
Posterior and inferior on L
+F SR RR
R rotation on L oblique axis (R/L)
+ on R
Deep on L
Posterior and inferior on R
+F SL RL

* R = right, L = left 
   + = positive, - = negative
   b/l = bilateral

Figure 3. Sacral diagnosis flow chart.