Short Right Leg Syndrome Assessment - Three Cardinal Signs
Physical therapists are taught to assess structural leg length in basic training. How often do they actually do so in practice? Many individuals are struggling with pain and injury from pelvic tilt across the Frontal Plane caused by a minor structural leg length difference. They have often been on the planet many decades...yet they were never told they have a leg length difference. In my clinical experience, the vast majority of clients present with a short right leg. It is always the right leg...sightings of even or near even legs are rare. I only see short left legs where an accident in their youth stunted its growth. This is Short Right Leg Syndrome.
My theory for the origin of SRLS is that in prehistoric times it gave mother and child a greater chance of survival. The two signature traits of SRLS are an elevated left hip and the resulting mild right leaning scoliosis elevates the right shoulder. We carry babies on our left hip…they just do not sit securely on the right side… and, similarly, we carry our bag over the right shoulder. So in the early primordial forest, baby secure on left hip, bag of charms, implements and provisions over the right shoulder…the right dominant arm is free for defence and work. This was the most successful model. Through evolutionary adaptation it is now hardwired into our genetics. This is living proof that earlier in our evolution, the upright bipedal hominids were predominantly right handed. If they were left handed we would be seeing short left legs. We do not see short left legs.
Symptomatically there are common patterns to SRLS. Some subjects show the signs but have no acute symptoms and manage fine with exercise, stretching and therapy to maintain flexibility through the pelvis and spine. Other subjects can be crippled and their life a misery. The symptoms are potentially wide ranging. Sub-acute symptoms reflect the common pattern. Acute symptoms manifest within the common pattern owing to postural and gait habits, loading or prior injury. Naturally, it cannot be assumed the cause is SRLS without confirming the anatomical asymmetry actually exists. In any event, clients will not believe you unless you can show and demonstrate it to them.
Three Cardinal Signs
In some instances, subjects exhibit symptoms resulting from a structural Leg Length Discrepancy that is so small it is difficult to detect by simple examination without the use of X-Ray equipment. However, the effect a LLD has on the body is amplified generating Cardinal Signs that are easy to detect by palpation. In practice, I use these Cardinal Signs to confirm the possibility a short leg is contributing to presenting symptoms before attempting a leg length assessment. The Three Cardinal Signs of SRLS are:
I. Anterior rotation of the left hip. That is, in a standing position the ASIS will be lower than the Iliac Crest as the hip rotates in the Sagittal Plane about the centre of rotation at the SIJ. The side of the short leg will typically be level.
II. Rigidity at the right hip from the QL's in the lower lumbar region through to the adductors in the groin. Tightening and tenderness often evident in the right QL's due to the right leaning pelvic tilt causing mild right sided disk bulging through the lumbar region. The SIJ can be stuck and manipulative therapists will attempt to mobilise the joint. ROM through the Femoro-Acetabular joint of the short leg will be limited…most noticeable in lateral rotation. Tractioning legs from the ankles reveals free movement through the joint on the side of the long left leg and a rigidity and woodenness at the hip of the short right leg.
III. Sign of mild right leaning scoliosis commonly displaying a right convexity through the Thoracic. More readily palpated than seen. With the subject prone a bulging rib cage and more developed and tight spinal erectors through the middle Thoracic on the side of the short leg. The opposite side will be flattened. Less common is a mild right leaning Lumbar scoliosis with Thoracic convexity to the left despite the right leaning Frontal pelvic tilt...owing to a switch back occurring in the vicinity of the juncture between the lumbar and thoracic.