Sacroiliac Joint Mobilization: Posterior to Anterior

Set-Up

1. The patient should be prone, face-down in a "cut-out" or headrest.
2. 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.
3. The table should be low enough so the practitioner needs to lean forward a small amount to get their chest over the intended segment with arms fully extended.
4. 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.

Unilateral Posterior to Anterior (PA) Mobilization

1. Find the inferior angle of the posterior superior iliac spine (PSIS)
2. Fall off medially, from the inferior angle of the posterior superior iliac spine. Generally, this positions your thumb or pisiform on the sacral base, at the level of the S2 or S3 segment.
3. You can use thumb-over-thumb or saddle grip.
   • It is recommended to use the saddle grip if possible. Although this makes palpation more difficult, the SIJ is a very stiff joint, that requires a significant amount of pressure to mobilize.
4. Check body mechanics to ensure the chest is over the target segment and the arms are straight.
5. Apply force in posterior to anterior direction.
6. You may need to try test oscillations at various "segments" to find a level that both feels stiff and moves when pressure is applied.

Mobilization:

1. Once you have located where you are going to apply force, start with small test oscillations to feel for articular motion and identify any exquisite tenderness.
2. 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.
3. Identify the mid-point between the first resistance barrier and articular end-range; approximately 50% resistance.
   • Grades - The amount of pressure required for this mobilization and the small amount of glide permitted at this joint make differentiating grades difficult if not impossible. Mobilizing the joint from first resistance barrier to the end of articular range is sufficient.
4. Oscillate at 1 - 2 pulses per second.
5. Continue oscillating until you feel a change in tissue resistance/joint stiffness.
   1. Strangely, this technique seems to be more effective when mobilization is performed at several segments, as if the sacrum was not fused. This may be due to the length of the joint surfaces, or the various interfaces of concave and convex surfaces within the joint, but clinically mobilizing 2 - 4 segments has resulted in better outcomes than mobilizing a single segment.