Set-Up
- The patient should be prone, face-down in a "cut-out" or headrest.
- The patient's arms should be supported in a comfortable position; however, not in full shoulder flexion (hands under forehead). Shoulder flexion may increase tension in the latissimus dorsi and thoracolumbar fascia.
- The table should be low enough so that leaning forward slightly allows the practitioner to get their chest over the lumbar spine, with arms fully extended and thumbs in position over the affected segment.
- Ideally, the set-up would allow the practitioner to oscillate pressure by gently rocking the torso (not by using grip or triceps strength).
- Note: It is worth spending some time reviewing the anatomy of the sacroiliac joint and practicing on a plastic model before practicing the technique on a colleague.
Central Posterior to Anterior (PA) Mobilization
- Place the lateral aspect of the hypothenar eminence on the spinous process of the intended segment.
- Place the other hand over the palpating hand by saddling the palpating hand between fingers 2 and 3 of the top hand.
- Check body mechanics to ensure the chest is over the target segment and the arms are straight.
- Apply force in posterior to anterior direction with a slight inclination toward the client's chest.
Unilateral PA
- Find the spinous process of the affected segment, or the segment exhibiting stiffness.
- Generally, the facet is a half segment lower than the spinous process of the associated superior vertebrae.
- Slide your thumbs (thumb over thumb) into the laminar trough over the facet.
- Apply force in posterior to anterior direction with a slight inclination toward the client's chest.
Refining Practice: Studies demonstrate that erector spinae activity may increase segmental stiffness, implying the patient should be relaxed and comfortable during PA mobilizations (69). Further, the least stiffness is exhibited when PA mobilizations are performed with a slight cranial inclination bias (70).
Mobilization:
- Once you have located the segment you wish to mobilize, start with small test oscillations to locate the facet, feel for articular motion, and identify any exquisite tenderness.
- When you are satisfied with your test motions, identify the amount of pressure required to reach the first resistance barrier (just before articular motion), and then identify the amount of pressure needed to reach the end of articular motion.
- Note: The end of articular motion is the point at which any further increase in pressure does not result in additional arthrokinematic motion.
- Identify the mid-point between the first resistance barrier and articular end-range; approximately 50% resistance.
- Grade III - Larger oscillations between the first resistance barrier and approximately 50% resistance. Note, these oscillations are large compared to grade IV oscillations, but are still very small motions.
- Grade IV - Small oscillations at 50% resistance or more.
- Oscillate at 1 - 2 pulses per second.
- Continue oscillating until you feel a change in tissue resistance/joint stiffness.
