Postural evaluation and support

by Dr. Mark Charrette

Upright stance creates unique functional demands on the human musculoskeletal system. Restoring structural integrity, relieving symptoms and pain, or improving musculoskeletal function involves working with a patient's upright posture, especially since structural misalignments are most apparent when the body is in the position of function. [1]

Standing creates a closed kinetic chain among the body's four main support systems: cervical, torso, pelvis, and feet. Forces are transmitted between the links of this chain in such a way that problems in one system can affect other systems higher up. Gravity and heel strike shock from walking are two examples of forces which affect the kinetic chain.

The postural foundation

Gravitational force is a significant factor in the structure and function of the feet, which are the foundation of human posture. The weightbearing position exposes the lower extremities to the greatest levels of stress; also, more problems appear than in a non-weightbearing posture. [2]

The feet support the body, allow movement, and absorb ground reaction forces during movement. Their integrity depends largely on the plantar vault, formed by the longitudinal, medial, and transverse arches. [3] Weakness in one or more of these arches can have negative consequences throughout the body.

Continuous strain while standing, walking, and running can stress pedal tissue to the point of plastic deformation. Laxity destroys motion control, leading to abnormal alignment and kinetic response. Excessive pronation is the most common form of hypermobility, and is a contributor to more chronic postural problems than any other foot disorder. [4]

The effects of excessive pronation can be traced through the body up to the spinal-pelvic complex. Abnormal inward rotation of the tibia and femur threaten the knee and can instigate inward hip rotation. The body is also at increased risk of shock stress due to plastic deformation, with symptoms such as osteoarthritis, tendinitis, and slow or incomplete recovery of other musculoskeletal conditions. [4]

Detecting structural imbalances

Many conditions, including disc degeneration, myofascial pain syndromes, and chronic strains, can be attributed to musculoskeletal dysfunctions and postural abnormalities. [5] The traditional methodology for clinical evaluation of posture requires the body to be in a standing, weightbearing position.

Ideal, efficient posture is maintained with minimal muscular effort. It is the result of sound skeletal structure, soft tissue integrity, and neurological control. Optimal balance of the spine's normal physiological curves contributes to healthy posture.

Structural imbalances or weakness in soft tissues may be difficult to detect, especially those which have developed insidiously in response to factors such as pedal imbalance. When the body is viewed as a closed kinetic chain (weightbearing), underlying causes of nonspecific pain can be more readily identified. Visual postural analysis is a matter of comparison between support systems (Table 1).

Table 1. Comparison of support systems

Postural support and stability

Correction of postural distortions can involve several modalities, depending on the extent and etiology of dysfunction. Specific chiropractic adjustments which improve alignment and mobility, and reduce fixations, may be adequate for short-term problems. The goal is to normalize range of motion and encourage a midpoint rest position for involved joints.

Custom-made, flexible orthotics that control the degree and duration of pronation can alleviate these symptoms related to pedal imbalance. [6] Orthotics improve support and alignment to enhance body structure and function, [7] and modify minor deficits that inhibit the integrity of the pedal foundation. [6]

A weightbearing casting method provides the most accurate picture of pedal imbalance and dysfunction for prescribing orthotic correction. [8] In a non-weightbearing, neutral position, even a flattened arch will exhibit a deceptive integrity. When casts are taken with the foot in the position of function, areas of weakness are easier to detect.

REFERENCES

1. Wu KK. "Foot Orthoses: Principles and Clinical Applications." Baltimore: Williams & Wilkins, 1990.

2. Hoppenfeld S. "Physical Examination of Spine and Extremities." Norwalk: Appleton Century Crofts, 1976.

3. Kapandji IA. "Physiology of Joints, Vol. 2, Lower Limb," 5th Ed. New York: Churchill Livingstone, 1987.

4. Root ML. "Clinical Biomechanics II: Normal and Abnormal Function of the Foot." Los Angeles: Clinical Biomechanics Corp., 1977.

5. Reilly B. "Practical Strategies in Outpatient Medicine." Philadelphia: WB Saunders Co., 1984.

6. Christensen KD. "Orthotics: do they really help a chiropractic patient?" ACA J of Chiro 1990; 27(4):63-71.

7. Kuhn DR, Yochum TR et al. "Immediate changes in the quadriceps femoris angle after insertion of an orthotic device." J Manip Physiol Ther 2002; 25(7):465-470.

8. Yochum TR, Rowe LJ, Barry MS. "Natural history of spondylosis and spondylolisthesis." In "Essentials of Skeletal Radiology" (2nd ed). Baltimore: Williams & Wilkins, 1996. 364.

(Dr. Mark N. Charrette is a 1980 summa cum laude graduate of Palmer College of Chiropractic. Over the past 15 years he has lectured extensively on spinal and extremity adjusting throughout the U.S., Europe, the Far East, and Australia. He received a Bachelor's degree from Illinois State University (summa cum laude) in 1976, where he was an NCAA All-American in 1974. Dr. Charrette is a featured speaker in Foot Levelers' 2003 Spring Seminar Series )