December 2006

The functional short leg

by Dr. Howard Loomis

In the October 2005 issue of The Chiropractic Journal, I started a series of columns outlining a screening examination that could be performed within two or three minutes. It would quickly identify the source or cause of a patient's symptoms.

I began that column by writing: "Successful doctors treat the cause of the problem, not the symptoms. They are able to quickly and accurately determine the source of the patient's stress, devise a plan of treatment, and confidently convey their findings to the patient. They specialize in helping problem cases‑‑the ones no one else can help. They solve these cases by identifying the specific causes of disorder, discomfort, or disease that have not been identified elsewhere." In succeeding months, I have detailed each step in that examination. This is the final column in that series.

Identifying the functional short leg has become a staple in chiropractic examinations. It is rightfully the starting point in many techniques for it obviously will influence all structures above it. Unfortunately, it has been my experience that often the true cause of the short leg, measured in either the prone or supine position, is never identified.

For example, does the short leg exist because of a collapsed arch or ankle pronation? Is degeneration of the knee cartilage beginning? Is there loss of range of motion in the hip joint, either external or internal? Is there a sacro‑iliac problem because of the short leg or is the short leg caused by muscle contraction in the lumbo‑sacro‑iliac region? No attempt will be made here to discuss the anatomical short leg since they are comprise such a small percentage of the patient base and are fully discussed in chiropractic texts.

Statistics

Studies of the occurrence of a short leg can be summarized as follows:

71% of the population has a leg length deficiency of 1/16"

33% of the population has a leg length deficiency of 3/16"

4% percent of the population has a leg length deficiency of 7/16"

A leg length deficiency of 3/16" to 1/4" is considered to be sufficient to produce low back pain. However, it should not be assumed that any leg deficiency is permanent. Unless there is a past history of surgery or fracture in the lower extremities, these inequalities should be considered as functional and correctable with chiropractic care.

Measuring for a short leg

Have the supine patient bend his or her knees and place the soles of the feet on the examining table. Align the feet to each other and compare the length of the big toes to that of the second toes. Morton's Syndrome is the presence of a second toe being longer than the first toe. This condition causes the weight‑bearing surface of the foot to shift laterally from the first metatarsal to the second metatarsal. This may occur in one or both feet and is not an unusual finding. It's estimated that 40% of the population has a second toe that is longer than the big toe.

Keep the patient's knees bent to check for problems above and below the knees.

Problems above the knee can be identified by placing your hands on front of the knees, over the patella. Observe if one femur appears to be longer than the other. In other words, the knee closest to the pelvis indicates a problem above the knee in the hip joint or the sacro‑iliac.

Problems below the knee are identified by placing your hands on top of the knees and comparing their height. The low knee indicates a problem below the knee, in the ankle or foot.

Next, have the patient straighten his or her legs and relax. Evaluate restricted hip rotation by grasping both feet by the heels. Raise the legs off the table slightly. Attempt to rotate the legs first inward and then outward. Compare the rotation of one side and then the other.

Limited internal rotation indicates an ilium in internal rotation and suggests the need to palpate down the medial thigh, medial tibia, and medial surface of the ankle looking for muscle contraction.

Limited external rotation indicates an ilium in external rotation and suggests palpating down the lateral thigh, lateral fibula, and lateral surface of the ankle looking for muscle contraction.

This test is used to ascertain chronicity and involvement of the hip joints. The knee is not being tested specifically here because there is no rotation in the knee joint when the knee is locked in extension, as it is when we perform this test.

Nevertheless, this test is useful in determining a prognosis for knee and hip degeneration. Prolonged restriction of internal rotation leads to knee degeneration due to compression stress on the knee. Prolonged restriction of external rotation leads to hip degeneration due to shearing stress on the hip.

It is important to eliminate these structural findings and prevent their continual recurrence. Only then can we begin to identify the hidden causes of chronic musculoskeletal problems which so often prevent our clinical success. This is what I call "The 2nd Factor in Chiropractic," and I'll begin that series next time.

(Dr. Loomis can be reached by mail at 6421 Enterprise Lane, Madison,WI 53719 or by phone at 800‑662‑2630. Visit his website at http://www.loomisenzymes.com.)