Short Leg Syndrome, Part Two

Article as seen in Massage Today Magazine November 2007

by Erik Dalton, Ph.D.

A highly debated postural issue begging for a logical explanation is the “short right-leg syndrome” (Fig. 1). Although an inferred awareness of right-sided limb-length shortness has existed for centuries, along with decades of published research, no one has provided a universally acceptable answer to two very important questions:

1. Why the unusual frequency of short right legs seen in clinic?
2. How does this common postural pattern cause compensatory hip, back and pelvic pain?

Let’s begin by reviewing notable research regarding functional and structural short right legs and then discuss theories, assessments and corrections that help deal with this troublesome disorder.  As Sir William Osler once stated, “In order to treat something, we must first be able to recognize it.” Any attempt to tackle limb-length discrepancy and associated compensations, armed with inadequate evaluation tools, surely will lead to failure and frustration. In the absence of radiographic measurements, massage therapists must develop keen palpatory and visual skills for detecting osseous and soft-tissue dysfunction. Aberrant patterns are best identified and classified using the acronym ART: Asymmetry, Restriction of motion, and Tissue-texture abnormality. Although numerous tests and treatment modalities have proven successful in treating short legs and associated compensations, we’ll focus on only a few fundamental myoskeletal techniques that add to your toolbox of touch.

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Fig. 1. Anatomic (structural) short right leg.

Fig. 2. Short right leg causing contralateral pelvic rotation.

Fig. 3. Low right-femoral head and sacral base with compensatory lumbar scoliosis (sidebent left, rotated right).

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Leg Length and Back Pain

In two exquisitely designed studies (1962 and 1983), Denslow and Chase measured leg-length discrepancy in 361 and 294 subjects presenting with low back pain.¹ Using the most advanced radiographic technology currently available, their papers (published in the American Academy of Osteopathy) reported the following findings concerning limb-length discrepancy:

• Significant incidence of short right legs (66 percent);
• Lumbar convexity to the short leg side (sidebent left – rotated right); and
• A high correlation depicting contralateral (left) pelvic rotation. (Fig. 2)

By comparing sagittal-plane femoral-head height and sacral base angulation (Fig. 3), the authors concluded that innominate bones rotate around the sacrum (iliosacral tilt). Transverse plane images revealed that the pelvis also can rotate as a block around the vertical lumbar spine. Denslow and Chase’s pioneering work helped biomedical researchers understand how shortened limbs torsion the pelvis, creating painful lumbar compensations. Their data not only confirmed leg-length findings conducted by previous researchers but also prompted new, more sophisticated imaging studies. In 2004, John H. Juhl, DO, reported that 68 percent of 421 low back pain patients presented radiographically with short right legs.²

Fig. 5. Contract/relax/assist technique to lengthen tight/short left QL.

Although leg, hip and pelvic corrections shouldn’t be based solely on supine test results, helpful information is derived by combining it with other exams such as prone leg-length tests. These oft-neglected prone assessments offer therapists additional clues for solving the limb- length puzzle. When prone, both ASISs are “pinned” to the table, thus preventing ilial rotation and allowing the therapist to isolate sacroiliac and axial skeletal joint dysfunction. Here’s a quick reference for differentiating supine from prone limb-length assessment: Supine: Tests leg-length differences resulting from iliosacral rotation, typically due to muscle imbalance. Prone: Tests leg-length inequality as the lumbar spine attempts to adapt to sacral-base unleveling in the presence of SI joint dysfunction.

Depending on the degree of leg-length shortness, compensations may travel all the way up through the cervical spine and into the cranium (Ascending Syndrome). Conversely, “key” restrictions sometimes begin in the head or neck and travel down the kinetic chain (Descending Syndrome), causing pelvic obliquity and adaptive leg-shortening (Figs. 6A and B). During the course of an examination, several simple tests help uncover the biomechanical root of the shortened leg. However, none are adequate to fully assess all possible causes. The Derifield (deer-field) Maneuver3 and others discussed below are useful in “weeding out” spinal and pelvic disorders.

Figs. 6A & B.

The second phase of testing begins with the client’s head in neutral with the therapist’s thumbs evaluating medial malleoli height. Once a visual measurement has been noted, the therapist’s hands slightly plantar-flex the client’s feet while slowly bending the knees to 90°, examining for any changes in heel height. Four possible findings may be noted during this test:

1. Short leg stays short. If one leg is anatomically short, no change in leg length should occur as the knee moves from extension into flexion (Fig. 8). Referral for foot orthotics may be necessary.

Fig. 8. Prone test; leg stays short in knee flexion and extension due to tibia and femur asymmetry.

Fig. 9A. Contract/relax/assist technique to de-rotate the pelvic bowl

Fig. 9B. Correction for a unilateral left-extended sacrum.

4. Heel Drop: With knees flexed 90°, the therapist allows both heels to drop toward the buttocks to see if one leg falls farther than the other. The heel falling farther usually is a positive indicator of a posterior sacral rotation on that side. This finding is noted as a positive Webster’s sign.⁴ A variety of spring tests can be used to identify and correct the torsion.

Neurological Explanations for Short Legs

When a short-right-legged client stands with each foot resting side by side on bathroom scales, a measurable weight-shift typically occurs to the low side. The Leaning Tower of Pisa demonstrates this normal law of physics. However, the Tower does not possess a nervous system. Several researchers including Kappler, Previc and Pope^5,6,7 believe that some individuals unconsciously resist this gravitational pull by sideshifting body weight to the left side, through a prenatal organizational system called cerebral lateralization. Their research theorizes that motor dominance overrides anatomical and gravitational factors in these individuals. It’s thought that right motor dominance has roots in fetal positioning during the third trimester, resulting in the brain’s lateralization process.⁸

Fig. 11. Right motor and left vestibular dominance.

In the brain, motor dominance typically crosses cortexes from left to right (left brain controls right side of the body). Conveniently, left vestibular dominance, which assists in balance, coordination and orientation, travels ipsilaterally down the left leg to allow left-sided weight bearing during right motor-dominant activities. For instance, a right motor-dominant person typically balances on their left leg to perform tasks such as kicking a ball (Fig. 11). Combining right motor and left vestibular dominance often results in a left-side-shifting maneuver of the pelvis over the vestibularly long left leg during standing (Fig. 12). This neurological postural shift helps explain many unusual pain patterns seen in clinic.

Fig. 12. Cerebral lateralization causes side-shifting over the vestibularly dominant left leg.

Short Leg Symptoms

Those with short right legs who bear more to the short right side usually report greater SI joint pain in the right hip and low back area. Examination of the sacrum often reveals a deep right sacral base, positive spring test for anteriorly fixated ilium and tender iliolumbar and sacroiliac ligaments. Conversely, motor-dominant clients who side-shift over the left leg usually experience greater left-sided SI joint pain and a positive spring test for a posteriorly fixated ilium. Symptoms worsen during prolonged walking or running, as overstretched abductors grind against the greater trochanter, creating bursitis, gluteus medius tendinosis and piriformis syndrome.

Since the human body rarely is symmetrical side to side, testing for loss of joint play often provides more reliable information than analyzing anatomical landmark findings. For decades, therapists have utilized spring tests to determine the presence (or absence) of joint-play in ankles, feet, hips and shoulders. Regrettably, spring tests are not as commonly used to evaluate spinal and sacroiliac joints. Therapists can benefit greatly by observing for common postural patterns during gait, checking anatomical landmarks, and spring-testing questionable structures to see if the findings have relative value.

Iliosacral, SI joint, and lumbar spine spring tests are valuable assessment and treatment tools that fit perfectly into a massage therapy format. Following the supine and prone leg-length tests, specific springing maneuvers can be used to verify findings and correct motion-restricted joints.

Since short limbs arise from biomechanical as well as neurological factors, therapists must take time to fully evaluate the client looking for common compensatory patterns such as the short right leg. Visual observation of the client’s gait alerts the therapist to the possibility of cerebral lateralization and accompanying pelvic side-shifting. Supine and prone exams should be compared with other anatomical landmark findings to determine whether iliosacral, sacroiliac or head and neck restrictions are responsible for limb-length problems. Discrepancies greater than 2 cm can be associated with scoliosis, pelvic obliquity and alterations in the normal walking cycle. From a functional standpoint, there is strong, though not conclusive, evidence of an associated increase in the incidence of low back pain and hip joint osteoarthritis.

References

1. Denslow J, Chase I, et al. Mechanical stresses in the human lumbar spine and pelvis. In: Postural Balance and Imbalance. Peterson B, ed. Indianapolis: American Academy of Osteopathy, 1983, pp. 76-82.
2. Juhl J. Prevalence of frontal plane pelvic postural asymmetry. J Am Acad Osteopath Assoc, October 2004;104(10):411-21.
3. Cooperstein R. The Derifield pelvic leg check: a kinesiological interpretation. Chiropractic Technique, 1991;3:60-65.
4. Bovee ML. The Essentials of the Orthopedic & Neurological Examination. Davenport, IA: Palmer College, 1977.
5. Kappler R. Postural balance and motion patterns. J Am Osteopath Assoc, May 1982;81(9):598-606.
6. Previc FH. A general theory concerning the prenatal origins of cerebral lateralization in humans. Psychol Rev, July 1991;98(3):299-334.
7. Pope R. The common compensatory pattern: its origin and relationship to the postural model. Am Acad Osteopath J. 2003;14(4):19-40.
8. Dalton E. Advanced Myoskeletal Techniques. Oklahoma City, OK: Freedom From Pain Institute, 2005, pp. 154-160.