Leg Length Discrepancy and Short Right Leg Syndrome
in the context of Remedial Therapy
Observations on Scoliosis from the Perspective of Remedial Therapy or "This is the Reason Most People Have a Pain in the Neck"
...Tom Bowen attributes it to Dural Drag working down the spine. I attribute it to Pelvic Tilt from a structural leg length discrepancy working up the spine...
In conjunction with studying structural leg length discrepancy, I began examining every client for the presence of scoliosis in 2014. I have only sighted two cases of acute scoliosis and recall less than a handful of cases that appeared to be near symmetrical. All other cases show the presence of mild scoliosis. Mild scoliosis is defined as deviation of the spine between 10 and 20 degrees of curvature in the Frontal plane. To be honest, I am not doing measurements but observing cases where the asymmetry is palpable and there is a symptomatic effect on the back, neck and shoulders. Many subjects have not been alerted to it by prior therapists and are not aware of the condition. Leg length discrepancy and the accompanying mild scoliosis through the Thoracic are key aspects of the mechanism for carrying baby on the left hip.
The illustration above is at the higher limit of a mild case. More commonly mild scoliosis can be difficult to see by direct observation. The primary method of identification I use is palpating the rib cage. Diversion of the spine consistently to one side crowds the ribcage, bulging the ribs on the side of convexity and flattening those opposite. Confirming signs will be an elevated shoulder and more heavily developed and tight spinal erectors through the middle Thoracic on the side of convexity. Shoulder elevation signs can be overwhelmed by injury. Muscular development in trained athletes will be more balanced.
Owing to the dominant genetic trait of a short right leg generating right leaning pelvic tilt in the Frontal plane, right convexity through the Thoracic is most common. Occasional instances of left convexity do present and typically have leg length discrepancy in the lower range that less convincingly encourages the spine to continue to the right through the Thoracic. I expect these exception cases will demonstrate right leaning diversion through the Lumbar spine matching pelvic tilt and flop into left convexity through the Thoracic but I lack x-ray evidence of this detail.
It is considered by some that Thoracic convexity is influenced by strain on the torso from the dominant side. That is, right handed individuals will demonstrate right convexity through the Thoracic. I can understand how this will be a contributory factor and...yes...90 percent of us are right handed and the majority of cases have right convexity. However, I have not observed this handedness in left convexity cases. Many are right handed. It is probable structural leg length discrepancy generating right leaning pelvic tilt is a greater influence.
With a right leaning pelvic tilt, the Sacrum being the foundation of the spine also tilts to the right and the Lumbar spine is encouraged into a rightward direction. The curve from the mild scoliosis generated is rightward in the lower regions of the spine and continues through to the upper Thoracic where it has now backed around on itself and is moving in a leftward direction. Tipping shoulder alignment into a left leaning tilt, the right shoulder is higher than the left. Hence, the Marilyn Munro off the shoulder look to the left. It is the left bra strap that falls off and shoulder bags are carried on the right shoulder. Exception cases with left convexity through the Thoracic having an elevated left shoulder and the off the shoulder look is to the right.
In relation to the mechanism for carrying baby, as a result of right leaning pelvic tilt and right convexity through the Thoracic, the centre of gravity in the upper back shifts slightly to the right. Counter balancing this, the hips shift to the left. So, the elevated and jutting left hip becomes the perfect perch for baby. A loosely draped left arm is all it takes to hold baby securely on the left hip. It is almost impossible to carry baby on the right hip without straining to distort our stance and make it work. In prehistoric times this increased the chances of survival for mother and child by freeing the strong right hand for work and defence. It was the most successful model. Through evolutionary adaptation the structurally short right leg has become a dominant genetic trait in our species.
Symptomatically, the unbalanced posture places strain on the upper back, neck and shoulders. The side of convexity is more affected. In right convexity shoulders are tilted upward on the right and leaning the head to the left, loading the right side of neck down through the upper trapezius, levator scapula and spinal erectors. In effect, the entire upper right quadrant is under strain requiring regular mobility and strengthening exercise or treatment to maintain comfort. The right vertebral extensors through the Thoracic are working 24/7 pulling down to keep the head erect. You will find these muscles on the side of convexity will be more highly developed and tighter than the opposite side. Athletes regularly mobilising and training their upper bodies will be more symmetrical and manage the asymmetry well. Less athletic and more sedentary individuals will have greater degrees of pain and discomfort from the constant strain of this mild scoliosis. It is a contributing factor in shoulder and arm issues on the side of convexity.
The same mechanism elevating left hip and dropping right hip geometrically distorts lumbar disk spacing incrementally squeezing disks on left side and opening up on the right; encouraging disks to be pushed out on the right. I suggest this is the cause for the common state of tightness and tenderness in the right QL’s and is likely to be a contributory factor for widespread low grade, non-catastrophic lumbar disk bulging. This is supported by several instances of MRI reports stating low level disk bulging to the right in all five Lumbar disks in cases of higher range leg length discrepancy. It has the potential to escalate under loading and impact to catastrophic lumbar disk bulge. Particularly, in those exception cases not demonstrating the First Cardinal Sign of SRLS of anterior rotation of the left hip which is an unconscious anatomic adjustment to functionally pull up the longer leg reducing pelvic tilt to some degree, making us feel more comfortable and protecting the spine.
The interpretation for symptomatic effects through neck and shoulder described above is contrary to general therapeutic doctrine. Discussion with several Osteopaths and Chiropractors reveals they are of the view that it more commonly originates in the neck or TMJ generating “Dural Drag” working down the spine. The consequent strain through the torso lifting the contra-lateral hip. This is also described by Tom Bowen as the typical postural presentation encountered in his practice. Interestingly, his description mirrors my description of the most common presentation of Short Right Leg Syndrome with a prominent Left Lower Limb Mechanism and mild scoliosis with right convexity through the Thoracic. He attributes it to Dural Drag working down the spine. I attribute it to Pelvic Tilt from a structural leg length discrepancy working up the spine. Until Tom or his present day advocates and other therapists demonstrate to me they have accounted for structural leg length discrepancy in their analysis of this postural condition, I am inclined to dismiss their theory of Dural Drag from the neck being the underlying causation. I have strong reservations about their method of structural leg length assessment. Much of it relying on poorly taken x-ray examination of the pelvis only. Additionally, the bulk of the therapeutic world would seem to assume leg length is even or near even. As a rule, it is not considered in medical examination