Dooley Noted: 6/26/2016
The lateral subsystem involves the biomechanical connections between the coronal plane pelvic stabilizers.
These muscles act to balance the pelvis on one side with its opposite side, using attachments at the ilium, pubis, lumbar spine, and femur.
The major muscles of the subsystem are described by Vleeming and depicted in this diagram:
The quadratus lumborum (QL), with its lumbar spine and Ilial attachments, help to hike the pelvis on a lumbar spine fixed point.
The QL works in concert with the opposite site hip adductors at the pubis and hip abductors at the ilium.
Because of their shared superior ilium attachments, QL and gluteus medius serve as the major balancers of coronal plane stability at this subsystem.
A simple single leg stance (SLS) or half kneeling stance can demonstrate the natural QL activation of the hiking side and the natural balance supported by gluteus medius on the stance side.
However, dysfunctional stance in lateral subsystem tissues may include the following:
1. A Trendelenberg sign, in which the patient has a pelvic drop to the contralateral side and a hip hike on the stance leg
2. A lateral flexion bias to one side, with lumbar spine movement superseding hip movement in the coronal plane
3. L5 disc pathology, creating down-regulation of hip abductor recruitment
4. History of unilateral lumbopelvic pain, with a constant awareness on the hip-dropped side due to eccentric loading of that QL
5. History of groin strain, especially on the same side of dysfunctional hip hike.
A sample case study:
My patient presented with a left hip hike on left SLS, instead of the typical R hip hike. Low back tightness was perceived, but with no pain perception.
The patient had been unsuccessfully stretching out his medial thigh and right low back, thinking that the painful spots were the ones that needed attention via stretching.
I agree they needed attention.
But they needed to properly shorten, not lengthen!
We verified this by looking at his lateral subsystem of muscle groups.
While his SLS resembled a Trendelenberg sign, he did not have L5 radiculopathy from disc herniation and no superior gluteal nerve impingement.
This poor gentleman had developed a hip hike from chronic left leg-crossing! He sat cross-legged, leaning towards his left leg for years at work.
As we down regulated his left QL activation, we discouraged the stretching of the already overly-stretched R QL and adductors.
We found a down-regulated left gluteus medius, left adductors, and R QL.
We used left knee down half kneeling to encourage left side hip stability while putting the left QL on stretch. This position also put the R QL on hike to encourage a more balanced pelvis bilaterally.
We also encouraged him not to cross his legs, to disable the dysfunctional habit that found his way into the current pattern.
If you have a chronic low back or groin tightness with which you crave to constantly stretch, consider that you may not need to stretch.
Or, you may be stretching the wrong things.
Get assessed and corrected for lateral subsystem issues.
As always, it’s your call.
– Dr. Kathy Dooley
