"Only one out of 10 may have an anatomical short leg." ... "I've never seen a short leg in 20 years." ... "Nine out of ten have an anatomical short leg." ... "Even if you do have one, it doesn't matter." ... "As little as 1/8" difference in leg length (4mm) is enough to cause scoliosis." ... "Up to 1/2" (12mm) difference can be tolerated before a problem exists."

Whenever there is a gathering of chiropractors, you may hear any or all of the above statements. Even professionals teaching their techniques will disagree and it's often enough to make practitioners violent to suggest that what they have been doing for years may not be valid.

By objectively presenting this information -- with both my opinion and those of others -- I do not expect readers to automatically change their opinions or accept the ideas and facts presented. I would hope that they will open their minds to lateral thinking and review their own opinions.

In an ideal world, everybody's legs would be created equal -- left legs were just as long as the right ones in all cases. In reality, however, prone or supine leg checks using the internal malleolus or bottom of the heels as the point of reference usually reveals an apparent difference.

Whatever technique one uses to adjust for this apparent anomaly can make instant apparent changes in this leg length. This proves that our technique "works." Why then doesn't the re-check beat out the changes made by the course of adjustments undertaken? Why does the re-check x-ray, more often than not, look the same. After all, the patients feel better. If they're fine when they leave the office, it must be a "holding problem," we rationalize.

All too often, the next step is to spend a lot of time, effort, thought (and occasionally money) making our "adjustments" to the leg length "hold." Legs -- we all agree -- should be equal in length, the pelvis should be level and the sacral base horizontal to facilitate a straight spine. This certainly makes sense and it's what most of us were taught in college. It must be right because that's what we've been trying to do all these years.

And so we persist in our therapeutic efforts, confident that we are doing all we can for our ailing patients until 10, 15 or 20 years later we begin to notice real changes being made in these peoples' spines, proven this time by the x-rays. The problem is that these changes are obviously degenerative ones and becoming more permanent with the passage of time. [1,4]

What have we done for these patients over these 20 years? Have we adjusted their stance, posture, spinal curve and individual vertebra to insure that the least amount of degenerative changes occur over the years thus facilitating free nerve expression to all parts of the body? Or have we dogmatically continued to adjust our patients using the obvious visual evidence of an initial correction as the criteria for more of the same? It would seem that the latter is the rule, not the exception.

Let's paint another hypothetical picture. Let's assume that more than 80% of the people coming into your office have anatomical short legs or difference in length between left and right sides. [6,7]

Knowing that a prone or supine leg check will always (or almost always) reveal an apparent leg length discrepancy, we are going to disregard this finding and dismiss it as a temporary or transitory changeable condition. We are, therefore, only going to check the leg lengths in the erect or standing position.

This presents a problem, for the very anatomical parts that we use to determine the length (heel or internal malleolus) are now flat on the floor, perfectly equal in height and beyond manipulative efforts. Obviously, we must measure the femur height, ilium height or some such configuration or combination.

Yet, we find these parts are not readily palpable, at least not to the fraction of inch or millimeter differences that we need to measure. Unfortunately our bodies were not made to facilitate this measurement and some of us are, due to overlying adipose tissue, less likely to come up with acceptable measurements. [2]

Taking this a step further, logic tells us that since both feet are on the floor and we have an even floor, we can forget about most things below the knee and concentrate on what we all have plenty of, standing x-rays. [1]

At this point, we can invest $20 in a draftsman's parallel rule (preferably the kind that has rubber rollers), place the rule edge even with the bottom edge of the film and roll it up until it just touches the top of the high femur head. Draw a line with a sharp, soft pencil across the pelvis to just above the low femur head. The ruler is now rolled down to the exact height of the lower femur head and another line is drawn, this time a short one. The difference in height is measured and we have the leg length difference. [5]

Some doubts as to the accuracy of the measurement may exist. "The difference is only 'rotation,' the patient is 'PI' on the left," is one explanation. This could be true but in fact, you would have to have a positioning error of 18 degrees to produce a 2mm difference in femur height x-ray shadow. [1]

I would suggest as a positioning exercise a piece of pine board 1" thick and about 12" x 24" with "stick on feet" placed about as wide apart as the heads of the femur. This board is placed and centered just below the bucky with appropriate instructions given to the patient as to where to stand. Touch the patellas to make sure that the knees are not bent and place the gluteals equally against the bucky. You now have a way to guarantee a positioning error of less than 5% -- far less than it takes to create a meaningful x-ray shadow deficiency.

Next month, Dr. Lange will demonstrate the difficulties in determining the "deficiency" of the anatomical short leg, and discuss the consequences of failing to find and act on this common abnormality.

1. Giles, Taylor: "Leg Length Inequality," JACA (Aust.), December 1985.

2. Jerome, John: "Measurable Mysteries," Outside, August 1984.

3. Dulhunty: "Sacroiliac Subluxation," JACA (Aust.), September 1985.

4. Silverman: "A Calcaneal Orthosis in the Treatment of Postural or Functional Scoliosis in Children," ACA Journal, December 1987.

5. Dishman: "Pedal Mechanics Affecting 'Short Leg' Measurements," M.P.I.'s Dynamic Chiropractic, February 1988.

6. Slosberg: "Activator Methods, An Update and Review," Today's Chiropractic, July/August 1988.

7. Pennell: "Diagnosis & Treatment of Leg Length Inequality," 1989.