Posture Relative to the Feet

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What’s the Connection?

The body is an interconnected chain of segments, with its base in the feet. Pedal instability can contribute to observable postural distortions, such as forward head carriage, as far up the chain as the cervical spine. Examining and caring for any detectable foot conditions should be an integral part of neck pain management.

Ideal cervical spine/head posture in the standing position requires the coordination of skeletal structure, soft tissue integrity and neurological control to resist adverse gravitational loading forces. An often overlooked factor is the role that pedal stability can play in the maintenance of proper cervical/head posture. Faulty foot biomechanics can have a negative impact on all supporting joints above the foot/ankle complex. In particular, an unbalanced pedal foundation may, over time, contribute to a postural anterior translation (forward head carriage) in the head and neck (Fig. 1, PDF). For maximum effectiveness, the healthcare professional seeking to care for a postural deviation in the cervical spine needs to evaluate the potential involvement of the pedal foundation, and to correct postural foot problems.

Posture

Upright posture and bipedal movement offer humans a highly functional form of ambulation, but they also developed a different variety of stressful forces on the connective tissues of the body—“the once horizontal mammalian spine wrenched upward to support the aspiring head and free the greedy hands, leaving the old vertebrate nerves and their armor crowded too closely together.”1 The original biomechanical human profile, directed by survival, was primarily a dynamic one—“built for mobility rather than stability.”2 Yet over time, human beings have assumed a less consistent, less dynamically optimum biomechanical physical stature on a daily basis. “Compared to primitive man living an outdoor life, civilized man has become a standing-around and a sitting-down animal rather than a running-around one.”3

A sedentary lifestyle and/or compromising posture places strain on the ligaments, tendons, muscle fibers, fasciae, cartilage and bone in an attempt to maintain equilibrium of the body. Many “painful disabling conditions of the soft tissues of the musculoskeletal system are directly or indirectly related to posture in standing, walking, moving, lying, sitting, bending, or lifting.”4 Up to one-third of workers in the United States is required to perform manual activities on a daily basis that are damaging to the musculoskeletal system.5 These potentially harmful tasks often involve stationary imbalanced postures as well as dynamically uncoordinated movements.

In dealing with neuromusculoskeletal health maintenance, it is basic and imperative that healthcare specialists take into account and include in their exams an evaluation of an individual’s habitual posture and its potential role in pain and disability. If postural faults were only of aesthetic consequence, the concern about them might be limited to appearance. But this is not the case, in that postural abnormalities may cause discomfort, pain, or deformity.4,6,7

The Biostatic Chain

During walking and running, the spine is one link in a biomechanical Kinetic Chain, where movement at one joint influences movement at other joints in the chain. This concept of a chain also applies to the body in a motionless, standing posture; however, the terms biomechanical static chain or biostatic chain are more appropriate, since directed movement is not involved. In either case, the chain extends from the feet through the ankle, tibia, knee, femur, hip joint, pelvis and spine—right up to the head.

The integrity and effectiveness of this chain depend upon a fine balance of body alignment and muscle restraining activity at each joint against gravitational pull downward. Passive stability is achieved when the center of gravity of each segment is aligned directly over the center of the supporting joint. When the body is erect and weight evenly distributed between the feet, there are minimal demands for muscle action, because there is no forward motion. While in theory stability of the biostatic chain should be realized without any muscle action at all, the fact that not one of the supporting joints (pelvis downward through feet) is locked means that the slightest sway (the beating of the heart, for example) can create an unstable alignment.2 Therefore, postural balance means a continuous involvement of the supporting skeletal structure and muscles.

A Chain Reaction of Distortions

In ideal standing posture, the feet evert to form an angle of 30˚, and a plumb line dropped from the sacral promontory falls midway between the feet onto a line between the navicular bones (Fig. 2, PDF).9 Pronation occurs when the superior aspect of the calcaneus tilts and rolls inward, bringing the talus with it. This releases the navicular from arthrodial articulation with the talus and jeopardizes the medial longitudinal arch. When collapsed, it can begin serial distortion that may extend to the occiput (Fig. 3, PDF).10

Because pronation involves the talus, it can draw the adjacent tibia into rotation. The movement extends further to the femur, bringing the greater trochanter forward and out. The piriformis muscle at the apex of the trochanter is then subjected to a windlass-type stretch. Due to its connection with second, third and fourth sacral segments, the sacrum at its articulation with the ilium on the involved side may be pulled into a subluxated anterior and inferior position.

When this occurs, the gluteus maximus muscle compensates by contracting to resist the downward and forward disposition of the pelvis. At its origin on the posterior third of the iliac crest, the gluteus maximus contraction may force the ilia portion of the innominate to rotate posteriorly. Thus begins a typical basic distortion.

Likewise, with the sacrum in an anterior and inferior position, the fifth lumbar vertebra is mobile. Following Lovett’s Law, it will rotate toward the side and introduce structural scoliosis.

According to Free, the trapezius muscle “may tighten on the same side as the hypertonic hamstring, creating an inferior occiput and an atlas laterality. Subluxations may occur at the atlanto-occipital or the atlanto-axial area, with cervical pain on the side of the tight hamstring. If this cervical compensation occurs, the patient will have pain on the entire side (cervical, thoracic, lumbar) and many times the leg and arm.”11 Porterfield writes that “the cervical spine may be only one component of neck pain complaints. Structures related to the upper extremity and head often are involved with the painful syndrome, and an examination of these structures reveals alteration in function.”12

Postural Evaluation

Clinical evaluation of the standing posture using relatively low-tech tools has been confirmed as valid and reliable by several recent studies.13-15 The original device used to evaluate posture was the plumb line, which served as a reference line for the effects of gravity on body alignment. The plumb line remains a useful tool, and Foot Levelers has expanded its evaluative usefulness with its PostureCheck® (Fig. 4, PDF).

A valuable procedure in postural evaluation is the assessment in the frontal and sagittal planes of the balance and alignment of the three major regional masses of the body (cervical, torso, pelvis), and their relationship to their base of support—the feet and legs. This method permits a rapid yet standardized determination of postural deviation from the optimal alignment, and can be used in prescribing specific corrective exercises.

When assessing cervical postural distortions in the sagittal plane, the most common is identified as anterior translation.16 Translation is the motion of a rigid body in which a straight line in the body always remains parallel to itself. “For example, if a boat is pushed smoothly in a straight line from position 1 to position 2 without pitching or rolling, it moves in pure translation” (Fig. 5, PDF).17

In anterior translation, the ear is forward of the AC joint and the bite line is level, creating the so-called “dowager’s hump”.18 In addition to the forward head, the evaluating clinician will also note an increased cervical lordosis, round shoulders, internally rotated humerus and kyphotic posture.

Lack of stability in the pedal foundation can lead to serial distortions and muscular stretching all the way up the spine. With foot pronation and the associated collapse of the anterior transverse arch, the base point of the body’s center of gravity shifts forward. This shifting causes a pelvic translation, which in turn produces a thoracic extension. At this point the head attempts to maintain its position over the vertical center of gravity, and therefore slides into anterior translation (Fig. 1, PDF). The body’s support is greatly reduced, and it must work harder to maintain a standing posture. Cailliet concluded that for every one inch of anterior translation, there is a ten-fold increase in muscular effort on the part of the supporting muscles of the cervical spine. This inefficiency results in a constant firing of these muscles.19

There are literally hundreds of clinical observations which suggest that a mutually detectable relationship appears to exist between a cervical anterior translation and a deviated pedal foundation (pronated feet). In order to provide your patient with optimal balance and stability, it is critical that you evaluate and treat both the cervical spine and the feet.

Adjust, Support, Rehab

Care for cervical anterior translation requires adjustments, functional orthotics for support and the use of an appropriate rehabilitative exercise regimen. Often, both muscle and joint dysfunction require correction,20 and appropriate strength should be developed to help minimize the potential of future injury.21

Cervical spine. For isotonic exercise of the cervical spine, the NECKSYS® Home Care System is a unique combination of a versatile, simple-to-use neck exerciser, cervical collar and a series of biomechanical exercises. The patient can be instructed within minutes and then, at home, perform the prescribed exercise of posterior translation (Fig. 6, PDF).

Thoracic spine. As mentioned in Porterfield, cervical anterior translation can be linked to weakness in the thoracic spine.12 The BACKSYS® Home Care System provides an easy-to-use, effective way to condition and strengthen back muscles affected by injury, illness, or postural deficits. In the case of thoracic extension, the appropriate exercise would be thoracic flexion (Fig. 7, PDF).22

Orthotic support. Orthotics are of special value in cervical anterior translation cases where foot pronation and arch ligament laxity have been observed. A flexible, custom-made orthotics addresses the excessive pronation and provides support for collapsed structures in the feet (Fig. 8, PDF).

Additional support. Many patients also benefit from the use of a support for their excessively stressed spinal areas. Two highly recommended products are the Postural Back Rest (PBR) to give support to the thoracic-lumbar spine during prolonged sitting, and the Pillo-Pedic® cervical support pillow to ensure proper neck and shoulder alignment during sleep.

References

  1. Sims M. Adam’s Navel: A Natural and Cultural History of the Human Form. New York: Viking, 2003.
  2. Perry J. Gait Analysis: Normal and Pathological Function. Thorofare, NJ: SLACK, Inc., 1992.
  3. Zacharkow D. Posture: Sitting, Standing, Chair Design and Exercise. Springfield, IL: Charles C. Thomas, 1988.
  4. Cailliet R. Soft Tissue Pain and Disability (2nd ed.). Philadelphia: F.A. Davis, 1988.
  5. Chaffin DB. The value of biomechanical assessments of problems of load handling, workplace layouts, and task demands. In: Hayes KC et al. (eds.) Biomechanics IX-B. Champaign, IL: Human Kinetics Pub., 1983.
  6. Kendall HO et al. Posture and Pain. Malabar, FL: Robert E. Krieger Pub. Co., Inc., 1992.
  7. Travell JG, Simons DG. Myofascial Pain and Dysfunction, The Trigger Point Manual, Vol. 2. Baltimore: Williams and Wilkins, 1992.
  8. Steindler A. Kinesiology of the Human Body Under Normal and Pathological Conditions (3rd ed.). Springfield, IL: Charles C. Thomas, 1970.
  9. Cailliet R. Foot and Ankle Pain (2nd ed.). Philadelphia: F.A. Davis, 1983.
  10. Greenawalt MH. Spinal Pelvic Stabilization (4th ed.). Roanoke, VA: Foot Levelers, Inc. 1990.
  11. Free RV. Some common denominators in spinal misalignments, part 2. Digest Chiro Econ 1988; 30(6): 128-129.
  12. Porterfield JA, DeRosa C. Mechanical Neck Pain: Perspectives in Functional Anatomy. Philadelphia: W.B. Saunders Co., 1995.
  13. Garrett TR, Youdas JW, Madson TJ. Reliability of measuring forward head posture in a clinical setting. JOSPT 1993; 17:155-160.
  14. Raine S, Twomey L. Posture of the head, shoulders and thoracic spine in comfortable erect standing. Austr J Physiother 1994; 40:25-32.
  15. Bullock-Saxton J. Postural alignment in standing: a repeatability study. Austr J Physiother 1993; 39:25-29.
  16. Harrison DD, ed. Spinal Biomechanics: A Chiropractic Perspective. Harrison Pubs. 1992.
  17. White AA, Panjabi MM. Clinical Biomechanics of the Spine (2nd ed.). Philadelphia: J.B. Lippincott Co., 1990.
  18. Christensen KD. Chiropractic Rehabilitation, Vol. 2: Cervical Spine. Ridgefield, WA: C.R.A. Publication Division, 1991.
  19. Cailliet R. Neck and Arm Pain. Philadelphia: F.A. Davis, 1981.
  20. Cibulka MT. Evaluation and treatment of cervical spine injuries. Clin Spts Med 1989; 8(4): 691-701.
  21. Cole AJ et al. Cervical spine athletic injuries. Sports Med 1994; 5(1): 37-68.
  22. Christensen KD. The big three. Success Express 1994; 15(1): 4-5.