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. This is an outline of one aspect of the assessment protocol for Short Right Leg Syndrome highlighting the use of Three Cardinal Signs.
Three Cardinal Signs
In some instances, subjects exhibit symptoms resulting from a structural Leg Length Discrepancy 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 feet 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.
First Cardinal Sign, Assessment of Hip Posture – Standing and Prone
Anterior rotation of the hip of the longer leg is an anatomical adjustment functionally shortening the longer leg, reducing the LLD functionally and partially reducing tilt across the Frontal Plane of the hips, affording the spine some protection and making us feel more comfortable standing. I rate the degree of rotation from Level successively through to Very High Range measuring the difference in height between the top corner of the ASIS and the Iliac Crest as follows:
a. Level to Mild Range, 10mm or less (0 to 6 degrees);
b. Medium Range, 20 – 40mm (8 to 15 degrees);
c. High Range, 50-60mm (18 to 22 degrees); and
d. Very High Range, greater than 60mm...the largest sighted being approximately 100mm (25 to 30 degrees).
Level to Mild Range is the ideal hip alignment in the upright standing position. It might be considered normal or good posture but it is not the norm. In my clinical experience, the majority of clients present with chronic left sided unilateral anterior hip rotation in the High Range.
There are exception cases who have a structural leg length discrepancy and do not exhibit the First Cardinal Sign. They are uncommon. Do not assume leg length is even or near even if the First Cardinal Sign of anterior rotation of the left hip is not present. Complete the examination for the other Cardinal Signs and leg length discrepancy tests before making conclusions.
I carry out an assessment of this aspect of hip posture following initial discussion of the client’s condition prior to treatment. Practitioner seated to the side of the client standing looking straight ahead. Noting Lordosis, Kyphosis, Forward Head Carriage, and degree of chest tightness. Hip orientation in the Sagittal Plane is examined by palpating the Iliac Crest and top corner of the ASIS to determine hip position on both left and right sides.
My preference is to do the standing assessment, however, it is also possible to do so with subject lying prone. In the standing assessment we are looking at the hip position in relation to a horizontal line parallel to the floor. In the prone position it is in relation to a vertical line perpendicular to the floor. I have some concern gravity force vectors rotated 90 degrees from the standing position may distort test results. I have not made a close study comparing the test in different positions, yet it does seem to give a similar indication of hip alignment. I resort to testing in the prone position when reacquainting myself with a particular client’s condition or checking for progress during the course of a treatment. It is a quick, non-invasive although sometimes ticklish test to carry out. I disagree with reports stating the prone position forces the rotated hip back into a neutral position.
Testing hip posture in the prone position, place the thumb on the Iliac Crest and forefinger on the top corner of the ASIS. Visually sighting the height difference front to back is not really possible. It becomes a judgment made by feel and estimating the distance off vertical. Comparison to the opposite side which you may have previously tested and know to be level aids judgement. If you are not confident with your ability to make this assessment in the prone position, refrain from doing so and rely on the standing assessment.
When supine on the treatment table, another test relevant to assessment of the First Cardinal Sign is the Thomas Test. Left hip being held in chronic anterior rotation shortens hip flexors (Iliacus in particular) and they will be tighter than the right hip flexors. Morphing the Thomas Test into a hip flexor stretch on the left side can be the quickest way to partially normalise hip position and alleviate acute symptoms in the backline of the left leg.
Sacro-Iliac Joint Assessment
Assessment I carry out of the SIJ is limited to palpating for sensitivity, pain, and any gross aberrations from the norm in terms of position and joint gap. It was not covered in my basic Remedial training. While this perspective might be considered rudimentary, it reveals the primary cause of common dysfunction along the backline of the lower limbs.
Hip rotation has a direct effect on the SIJ. Client standing, back to the practitioner, palpate SIJ’s with thumbs to determine sensitivity or degree of pain present in each side. Take care to question the client closely on this, comparing side to side. Light to moderate pressure on the SIJ should elicit no pain or sensitivity in a normal joint. Clients will be inclined to disregard low level discomfort and report no problem.
Where a hip has been held in a chronically rotated position there is frequently discomfort and dysfunction at the SIJ. Not all cases of chronic hip rotation generate pain in the SIJ, nevertheless, the tightness present in the soft tissues of the joint due to ligamental twist and compression through the cartilage from the Spanish Windlass effect can cause energetic blockage that will affect the lower limb causing, at the least, a subtle thickening and tightening along the backline of the lower limb from gluteals through to the plantar fascia. In some cases, Medium Range hip rotation is sufficient to do so. High Range hip rotation will almost always have this effect yet there are exceptions...these are individuals with hyper-mobile joints and soft muscle tone.
Right side SIJ pain can be present due to right sided lumbro-sacral dysfunction typically accompanying right leaning scoliosis. It is less common than left side issues. This had me perplexed for quite awhile. Hip posture was perfectly fine, little or no rotational stress being applied to the right SIJ as we frequently see on the rotated and twisted left side but nevertheless high degrees of pain and sensitivity can be present. I did speculate right side mobility restrictions both in the lumbar region and the hip might force the SIJ to over mobilise and become aggravated. There may be some truth to this. However, I do notice a direct correlation between tightness and pain in the QL’s and SIJ pain. This condition is frequently sighted in SRLS cases. It is discussed further as a component of the Second Cardinal Sign
Second Cardinal Sign, Assessment for Rigidity at the Right Hip
I suggest rigidity noted at the right hip tractioning from the ankles is due to two factors. Firstly, the Pendulum Effect causing uneven footfall and, secondly, mild right leaning scoliosis causing right sided lumbro-sacral dysfunction.
With the Pendulum Effect on the short right leg, there is a momentary hesitation before planting the right foot with each and every step. Footfall is uneven…solid on the left and hesitant or lighter on the right. The right hip is ever so slightly forced to tense and hang on while the foot searches for the ground rather than confidently plant. In the course of time, the hip becomes rigid from the strain. The right Adductor Magnus tightens. It is clearly evident the right Adductors are consistently tighter than the left when stretching. Rotation of the Femur in the Acetablum will be restricted.
Additionally, owing to an elevated left hip and inferior right hip, the spine's foundation at the sacrum is tilted to the right causing a right leaning scoliosis. The lumbar vertebrae are not parallel, opening wider to the right and compressed closer together on the left. Geometrically forming a slight wedge shape in the disk spacing that applies pressure forcing disks to bulge to the right. Mild and rarely catastrophic, nevertheless causing tightness and tenderness in the QL's. While in a normal position and not rotated, the right SIJ frequently becomes locked and rigid causing manipulative therapists to attempt joint mobilisation. This dysfunction and rigidity contributes to the woodenness through the right hip generally. When escalating to more acute levels, pain in the SIJ is noted. Ultimately, catastrophic disk bulges may occur.
Third Cardinal Sign, Assessment for Right Leaning Scoliosis
In most cases, the degree of right leaning scoliosis present is mild. Virtually unnoticeable to visual inspection and the client is usually unaware of it. The client may never have been told of its presence. Yet it can be the cause for their history of upper back and neck issues of discomfort and tightness, pain and/or headaches. It can be cause for low back pain and disk bulging through the lumbar region. It is another piece of evidence supporting the fact a LLD exists.
With client prone on the table, mild scoliosis is best observed by palpating the ribcage. The most common is right leaning scoliosis with convexity to the right through the Thoracic. This causes bulging in the right costals and flattens the left. A greater degree of muscle development and tightness is present in the right spinal erectors. The right shoulder will be elevated over the left.
Less common is a right leaning pelvic tilt with a scoliosis exhibiting a left convexity through the Thoracic as a result of a double switch back in the region of the lumbo-thoracic junction. Bulging of the left costals and flattened right costals will be evident. I find left convexity cases are typically instances of low range SRLS, that is; the spines of individuals with smaller LLD's are more likely to veer either way from the Thoracic than those with a larger difference. The larger leg length difference creating a steeper pelvic tilt exerts a stronger right leaning force driving the spine to the right and resulting in more assured cases of right convexity through the Thoracic.