Embryology - The Key to Understanding the Inherited
Foot Structures that Result in Chronic Muscle and Joint Pain
Inventor and Designer of Postural Control Insoles
Published in the Podiatry Forum: Anatomical Origin of Forefoot Varus Malalignment - 23rd September, 2012
Below I have delineated several key axioms that are presented in almost every embryological textbook:
The following two axioms are eluded to only. I have developed these concepts more fully in my clinical research (Rothbart BA 2002. Medial Column Foot Systems: An Innovative Tool for Improving Posture. Journal Bodywork and Movement Therapies)
KEY EVENTS in Late Embryogenesis (approximately Week 6 - Week 8 Post Ovulation) - which can result in inherited abnormal foot structure - summarized:
I. The Clubfoot Deformity
II. The PreClinical Clubfoot Deformity
Around CS22, the heel bone has partially unwound (and with it, the lateral embryological column of the foot). If the ontogenetic torsional development of the foot stops at this stage, the heel bone would still retain a slight valgus torsion, but the entire embryological medial column of the foot would be in supinatus.
What would this foot look like?
I suggest that when the PreClinical Clubfoot is placed into its anatomical standing (obviously post gestation) neutral position (e.g., Subtalar Joint Congruity - not Roots 1/3 - 2/3rds definition)
III. The Primus Metatarsus Supinatus Foot Structure (AKA Rothbarts Foot)
If the foot's ontogenetic torsional development stops prematurely in Late CS22/EarlyCS23, the calcaneus would have completed its' OTD. But the talus would still retain some of its supinatus (and with it the medial column of the foot).
What would this foot look like?
Measuring Rothbarts Foot
In the mid 1990s, I approached Dr Cummings and Higbie at Georgia State University. I suggested a study to see if Rothbarts foot could be reliably measured clinically. The results of there study can be accessed in the following publication: Cummings GS, Higbie EJ 1997. A weight bearing method for determining forefoot posting for orthotic fabrication. Physiotherapy Research International, Vol 2(1):42-50. [This study was funded by a grant from the College o Health Sciences at Georgia State University]
Any one of these three foot structures will eventually result in chronic muscle and joint pain throughout the body.
Anatomical Origin of Forefoot Varus Malalignment
Rebecca S. Lufler, T. M. Hoagland, Jingbo Niu, and K. Douglas Gross
J Am Podiatr Med Assoc 2012;102 390-395
Background: Forefoot varus malalignment is clinically defined as a nonweightbearing inversion of the metatarsal heads relative to a vertical bisection of the calcaneus in subtalar joint neutral. Although often targeted for treatment with foot orthoses, the etiology of forefoot varus malalignment has been debated and may involve an unalterable bony torsion of the talus.
Methods: Forty-nine feet from 25 cadavers underwent bilateral measurement of forefoot alignment using adapted clinical methods, followed by dissection and measurement of bony talar torsion. The relationship between forefoot alignment and talar torsion was determined using the Pearson correlation coefficient.
Results: Mean ± SD forefoot alignment was −0.9° ± 9.8° (valgus) and bony talar torsion was 32.8° ± 5.3° valgus. There was no association between forefoot alignment and talar torsion (r = 0.18; 95% confidence interval, −0.11 to 0.44; P = .22).
Conclusions: These findings may have implications for the treatment of forefoot varus since they suggest that the source of forefoot varus malalignment may be found in an alterable soft-tissue deformity rather than in an unalterable bony torsion of the talus.
I find Lufler's study very interesting but flawed. I believe her conclusions are flawed for several reasons:
A study that would definitively prove (or disprove) the correlation between talar torsion and the position of the embryological medial column of the foot would be:
Measure for the Primus Metatarsus Supinatus Foot structure (as described by myself and Cummings and Higbie).
Then take that same foot, after death, strip it down to the bony structure and measure the talar torson directly off the foot.
Compare your measurements. Do they correlate or not. That is, does one see an incomplete torsional development of the talar head and neck, or not.
For obvious reasons, this would be a very difficult study to conduct.
What exactly is forefoot varus and forefoot supinatus?
Podiatrists use these terms to describe connective tissue changes in the foot resulting from positional shifts.
However, one must keep in mind that these terms are used to describe symptoms (albeit positional symptoms), not primary pathology (etiology).
So, the question remains: what is the cause of forefoot varus or forefoot supinatus. All the explanations I have read to date (including some of the very complex biomechanical explanations) do not isolate primary causes, but instead, describe in great detail a series of interlinking positional shifts leading to the varus or valgus forefoot.
My first tenant in any therapy is to first isolate (determine) the cause of the symptoms. And then treat that cause directly.
If one treats symptoms (e.g., forefoot varus), the patient will end up in a life long process of pain management. Something that is very frustrating and expensive for the patient and should be avoided, if at all posssible.