Understanding the Mechanism of Plantar Fascitis

:dropcap_open:A:dropcap_close:s chiropractors, our primary focus of care is the chiropractic adjustment. Based on our education in science, art and philosophy, we decide how and where to apply the chiropractic adjustment. Our treatment of a patient’s condition is based on the reduction or stabilization of the resulting subluxation complexes. We listen to our patients’ concerns and answer their questions, but we know that the expression of pain is not the finite reason for our care. We do not let symptoms dictate what we feel is the underlying cause of a patient’s complaint. For example, we know biomechanically and physiologically that subluxations in the lumbar spine can be a contributing factor in neck pain and headaches. However, when a patient’s complaint is not spine related, we have a tendency to use modalities, hot/cold application, give a recommendation to change shoes, ergonomic correction at our work stations, and often we treat the symptom instead of the underlying factor.

footbones2I get numerous emails from doctors who have questions regarding plantar fascia conditions. It is a common ailment for runners, but anyone can develop plantar fascitis. You probably have more patients with plantar fascia problems than you realize because the first signs and symptoms are usually foot pain with difficulty walking when arising out of bed in the morning. Once they have walked a little the pain usually resolves. When they come into our offices later in the day for their other complaints, they might not mention the condition. 
Let’s review the anatomy of the foot. Structurally the foot is made up of three arches: lateral longitudinal, anterior transverse and medial longitudinal. These arches form the rigid foundation of the foot, thus the importance of maintaining anatomical height. On radiographic views we can use the landmarks of the cyma line, which demonstrates an S-shaped curve between the talonavicular and calcaneocuboid joints. As the foot transfers the lateral weightbearing forces medial, the navicular drops (rolls inward or pronates), but the talus also slides anteriorly. During supination the talus posteriorly glides. The normal heel-to-toe transition that is important in having a symmetrical gait must have symmetry between pronation and supination. If the talus is constantly being translated forward excessively, the calcaneous will start to shift posterior and superior, causing more tension on the plantar fascia by further lengthening.

We know that the plantar fascia pain is the result of excessive traction of the fascia. Wolff’s law tells us the mechanical stresses will influence and cause hard and soft tissue to distort in direct correlation to the amount of stress imposed on them. 1 Thus, there is a possibility of a heel spur developing. Since the spur is last in forming, the pain is more a result of the excessive tension being placed on the plantar fascia.
If a patient demonstrates excessive foot pronation or hyperpronation, then the foot is more flexible, with fallen arches. Effective treatment of the condition must include stabilization of the asymmetrical patterning that the foot is going through. Commonly observed in this patient is reduced dorsiflexion of the foot and ankle. This is usually the result of a tight Achilles tendon, for which the foot must compensate throughout the stance phase of the gait cycle. This creates even more stress on the plantar fascia. For additional anatomical and biomechanical understanding, review the windlass effect that John Hicks first described in 1954.2

When we consider the biomechanical phenomenon that takes place in the foot during the weightbearing portion of the gait cycle, we can see why Leonardo Da Vinci stated, “The human foot is a masterpiece of engineering and a work of art.” So in our treatment plan we must consider adjusting the foot to make sure all joints are moving normally, as well as evaluate for weakened musculature or tight tissue structures like the anterior and posterior tibialis and the Achilles tendon. Scan the patient to identify their pronation index (which helps determine if stabilizing orthotics should be recommended). Possible shoe-type recommendations may be necessary based on foot structure and activity levels. It is extremely important to evaluate the gait cycle once you have made your corrections and recommendations. If compensatory patterns were being developed from favoring the pain and/or restricted movements resulting from subluxations, then some neuromuscular re-education may be necessary to further bring about a symmetrical gait cycle for a patient.
  1. Frost HM. Wolff’s Law and bone’s structural adaptations to mechanical usage: an overview for clinicians Angle Orthod. 1994;64(3):175-88. 
  2. Malone TR, Bolgla LA. Plantar Fasciitis and the Windlass Mechanism: A Biomechanical Link to Clinical Practice. J Athl Train. 2004 Jan-Mar;39(1):77–82.
A 1980 graduate of Palmer College of Chiropractic, Dr. Kirk Lee is a member of the Palmer College of Chiropractic Post Graduate Faculty and Parker College of Chiropractic Post Graduate Faculty. He has lectured nationwide on sports injuries and the adolescent athlete, and currently practices in Albion, Michigan.

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