Low back pain often results from various forms of sacroiliac dysfunction. Of the ten ways the sacrum can become stuck “crooked” between the two innominate bones; the most common is labeled (in osteopathic terminology) a “unilateral flexed sacrum”. Commonly referred to as “Mall Back”, this SI joint fixation occurs during prolonged standing with weight bearing on one leg. When the individual’s right leg supports more weight, the body side-shifts over the right “hip-hiked” ilium causing the sacrum to side bend left and rotate right (across an oblique axis) as seen below. Pain arises when the deep left sacral base (sulci) gets stuck in this flexed position. To make matters worse, L5 often tries to compensate by flexing, rotating and side bending left (FRSL) which hyperexcites joint mechanoreceptors as the left L5-S1 facets are crammed together.
Those suffering this onerous postural disorder typically experience generalized hip and low back pain. Oddly, 95 percent of all unilateral flexed sacrums occur on the left. Unlike sciatic-like sacroiliac dysfunctions such as backward sacral torsions, the longer the client stands, the more localized the low back pain becomes.
This is primarily due to sinuvertebral nerve irritation from overstretched nerve dura, posterior longitudinal ligament, iliolumbar ligaments and joint capsules. Since the annular fibers of the L5-S1 intervertebral disc also receive nerve supply from the sinuvertebral nerve, it can also become a major pain-generator as it is compressed and torsioned.
To assess this dysfunction, therapist’s thumbs palpate both sacral bases noting which sulcus is deepest. If the left sacral base is more anterior, the sacrum is stuck in right rotation. By sliding the thumbs down to the sacrum’s inferior lateral angle (ILA), the therapist can determine which side is more inferior. If the left inferior lateral angle is more inferior than the right, the pain is probably emanating from a left unilateral flexed sacrum.
The left sacral base has moved anterior and inferior and is dragging on dural membrane causing the aching back. The myoskeletal muscle energy technique demonstrated below is usually successful in correcting this prevalent chronic low back/hip complaint.
Addressing the left unilateral flexed sacrum.
With the client lying on her right side (knees and hips flexed), therapist grasps client’s left wrist with his right hand.
Therapist’s left thenar eminence contacts client’s inferior left sacral border just superior to the coccyx.
A slow, sustained counter-force develops as therapist gently pulls on client’s left arm while his left palm braces at the sacrum.
The client is asked to inhale and hold to a count of five while gently shrugging her left shoulder against the therapist’s isometric resistance.
As the client exhales, the therapist takes up the slack by lightly pulling on the client’s arm while maintaining a constant “scooping” pressure on the inferior sacral angle.
Anterior/superior ILA palm pressure causes the left sacral base to begin moving posteriorly into its proper position. As the therapist’s right arm left rotates the client’s trunk, L5 helps push the left sacral base posteriorly. Repeat procedure three to five times and re-check for restoration of sacral base and ILA symmetry. Once proper function is restored to the left SI joint, the lumbosacral junction regains normal reciprocal movement during the walking cycle.
Therapists should remember that most sacroiliac dysfunctions are associated with length/tension imbalances in the psoas, piriformis, QL, biceps femoris and gluteal muscles. Two major culprits contributing to sciatic-type radicular pain in the presence of a clean MRI are the piriformis and biceps femoris muscles. Unilateral sustained hypercontraction in the biceps femoris is particularly troublesome. Since this lateral hamstring often takes its origin at the sacrum instead of the ischial tuberosity, fascial contractures and sustained myospasm can cause a constant drag on the sacrum and dural membrane destabilizing the entire pelvic girdle. Therefore, the first step in relieving all sacroiliac dysfunctions is restoration of balance to all muscle groups attaching to the pelvis from below and above.
Obviously, hypertonic muscles require restoration of length while hypotonic muscles need to be manually tonified. Once pr! oper myofascial balance and muscle firing order is established in all soft tissues attaching to the pelvis, any remaining bony asymmetry can be assessed and corrected. Other musculoligamentous causes of SI joint and coccyx dysfunctions will be discussed in future newsletters.