Occam's Razon or the Law of Parsimony

Here is another example of how structure defines function:

The animation below is a patient diagnosed as having the Primus Metatarsus Supinatus deformity (RFS).



At heel contact the right foot is near its anatomical np (STJ np / joint congruity).

• This is exactly what we would expect because the calcaneus in the RFS (PMS deformity) has fully unwound (no residual supinatus).
• This places the plantar suface on the heel bone on the ground, a very stable position. Its' motion is being directed by Hip Drive pronation.

At midstance right foot is abnormally pronated (e.g., gravity drive pronation).

• This occurs because in the RFS, the talus,(and with it, the entire embryological column of the foot) is in supinatus. This places ONLY the FIRST metatarsal (not the remaining metatarsals) in a structurally inverted and elevated position relative to the ground.
• Gravity forces the 1st metatarsal downward until it rests on the ground (e.g., forces the foot into gravity drive pronation)

 

Another example of how structure determines function:

The animation below is a patient diagnosed as having the PreClinical Clubfoot Deformity (PCFD), a foot deformity in which both the calcaneus and embryological medial column of the foot are structurally in supinatus (In the RFS, only the medial column of the foot has retained its' supinatus)




At heel contact, both feet (white arrows) are in gravity drive (abnormal) pronation.

• This is the result of the retention of calcaneal supinatus (plantar surface of the heel bone is structurally inverted relative to the ground)

• Gravity forces the heel bone to rotated inward until the entire bottom surface of the calcaneus rests on the ground

At midstance, both feet continue to abnormally pronate (e.g., gravity drive pronation) when they should be resupinating

• This occurs because the talus,(and with it, the entire embryological column of the foot) is in supinatus. This places ONLY the FIRST metatarsal (not the remaining metatarsals) in a structurally inverted and elevated position relative to the ground.

• Gravity forces the 1st metatarsal downward until it rests on the ground (e.g., forces the foot into gravity drive pronation)

At heel lift, the windlass effect has:

• resupinated the left foot

• The right foot remains abnormally pronated

This has occurred, in this instance, due to the descending disruption in the gait pattern coming from the malocclusion.


Notice how the structure has define how the foot moves during gait.

• The RFS enters gravity drive pronation only when weight has transferred over the ILA and into the forefoot.

• The PCFD enters gravity drive immediately at HC and continues in gravity drive pronation throughout its' stance phase. (The PCFD is the cause of the functional flatfooted gait pattern).

 

Knee Bend Test used to make a differential diagnosis (For directions on how to run the KBT, click here)



Above is the Knee Bend Test used to differentiate RFS from the PCFD

When the weight is over the heel bone (as occurs at heel contact to foot flat)

• RFS is functioning around Hip Drive Pronation
• PCFD is functioning around Gravity Drive Pronation

When the weight is transferred over the ILA to the forefoot

• RFS is functioning around Gravity Drive Pronation
• PCFD continues to function around Gravity Drive Pronation

 

Another example of the Knee Bend Test

Patient diagnosed with PCFD

 

Gravity Drive Pronation



In the above illustration (left foot) the pelvis, and with it, the femur and tibia, are rotating counter clockwise. This should be supinating the left foot. But, as you can see, the foot is pronating, that is, it is in Gravity Drive Pronation.

Gravity is forcing the 1st metatarsal and hallux, which are in supinatus (along with the entire medial column of the foot), to rotate downward until the 1st metatarsal and hallux rest on the ground.

Note that the lesser metatarsals are resting on the ground. Only the first metatarsal is in supinatus (structurally inverted and elevated).

This is what distinguishes the difference between Root's Forefoot Varum and RFS (Rothbarts Foot Structure):

Root's Forefoot Varum

• Metatarsals 1-4 are inverted relative to the ground
• No deformity in the medial column of the foot

RFS (Primus Metatarsus Supinatus foot deformity)

• Only the first metatarsal is in supinatus, structurally inverted and elevated relative to the ground. The lesser metatarsals rest on the ground (no positional/structural inversion as described in Root's forefoot varum)
• The entire medial column of the foot is in supinatus

 

Structure not only defines function, structure also determines therapy. Below is a gait analysis taken from a patient diagnosed with a RFS, with and without insoles.



Using a proprioceptive signal (insole), notice the attenuation of gravity drive pronation at Foot Flat. The proprioceptive signal was place underneath the medial column of the foot, extending from the internal cuneiform, distally, to the hallux.

In this case, a generic 3.5mms insole was used, sold by a plethora of distributors throughout the world.

Knowing where the supinatus was located in this foot deformity determined where the proprioceptive signal needed to be applied - directly inferior to the structural aberration.

 

Another example where structure determines therapy



This patient was diagnosed as having RFS. A generic 6mms insole was prescribed. Note the dramatic attenuation of midstance gravity drive (abnormal) pronation (green arrow)

This highlights another difference when comparing RFS to forefoot varum; e.g., how they are treated:

• As a student (1967) I was taught to use a forefoot varus wedge extending under all 5 metatarsal heads, apex under the 1st met, nadir under the 5th met.

• The proprioceptive wedge prescribed for the RFS extends under the medial column of the foot. This includes the 1st metatarsal only (apex of the wedge medially, nadir of the wedge laterally).

Controlling abnormal pronation is the keystone and accepted paradigm in postural therapy.

• Axiomatically, So goes the posture, So goes the musculoskeletal pain.

That is - improving the patient's posture (via attenuating gravity drive pronation), dramatically decreases their musculoskeletal pain. (Recent research suggests the scope of improvement also impacts cranial, dental and mental symptoms)

• Rothbart BA 2013. Prescriptive Insoles and Dental Orthotics Change the Frontal Plane Position of the Atlas (C1), Mastoid, Malar, Temporal and Sphenoid Bones: A Preliminary Study. Journal of Cranio Manidibular and Sleep Practice, Vol 31(4):300-308.

• Rothbart BA 2014. Malocclusion and Abnormal Foot Motion.Cranio UK (Journal of the British Society for the Study of Craniomandibular Disorders), Issue No. 1, pp 26-29.

• Rothbart BA 2021. Alteration in Plantar Pressure Gradients (foot function) Linked to Alterations in Brain Wave Activity

 

I am still not convinced that classification of inherited foot structures based on foot embryogenesis at 12 weeks is the way forward, simply because so much happens between week 12 and a 30 year old patient presenting with foot related pain .
Footwear, for example, has a huge role to play .

Yes ,understanding why things are as they are in a presenting patient is key to treatment but can you prove, that with regard to the foot , the particular developmental patterns you point out at week 12 will have consistent consequence for the subsequent adult ?

My understanding is that fetuses develop at different rates with regard to male/ female, good diet/ poor diet etc .

From D'Aout et al -a typically shod foot vs an hab unshod foot .Form and function differ a lot between the two and a classification that ignores development after 12 weeks is ,IMO , much less useful than one which describes the situation in front of you .

(If you don't mind me saying so you do seem to have a better grasp of the importance of the muscles of the foot than many.)

 

Hi Gerald,

To answer your comments:

You wrote:

"My understanding is that fetuses develop at different rates with regard to male/ female, good diet/ poor diet etc"

• I agree. There are also teratogenic factors, such as radiation, maternal infections, chemicals and drugs that can result in congenital malformations. But far and above these considerations, the most common congenital foot deformations we see as Podiatrists (IMO) are the ones I listed above.

"Foot wear is also a factor"

• I agree. Foot wear is the weak link in treating RFS and PCFD. For example, if the patient wears his proprioceptive insoles in a shoe that the sole quickly compresses, the effectiveness of the proprioceptive signal is compromised.

" Shod foot vs an hab unshod foot, form and function differ"

• Absolutely. However, no matter how strong the intrinsic and extrinsic muscles of the foot have been developed, in time their feet will fatigue and collapse against the ever present gravitation pull of mother earth, if they have either the RFS or PCFD.

• I had a chance to examine the indigenous Mexican Mesoamerican population (specifically the Mixteco and Chol). Many had never worn any type of footwear. I found RFS and PCFD deformities in this population. Gait analyses, LRT and KBT demonstrated they also functioned around gravity drive pronation. That even with strong musculature, their feet collapsed (abnormally pronated) when they walked.

"A classification that ignores development after 12 weeks is much less useful than one which describes the situation in front of you"

• I agree and disagree. Absolutely we must treat the situation in front of us. But in order to do so effectively we need to isolate the primary etiology (that is, not just treat the symptoms).

• Understanding the embryological foot types provides a very powerful insight and tool in the differential diagnosis. It also provides the logic and direction in using proprioceptive insoles when either the RFS or PCFD is diagnosed.

 

You classified the feet of these people without any reference to foot embryogenesis at 12 weeks so your classification does not need to reference this aspect at all .

As far as I am aware any connection between foot embryogenesis at 12 weeks and the foot types in your classification is purely speculative .

 

Hi Gerald,

You stated that “As far as I am aware any connection between foot embryogenesis at 12 weeks and the foot types in your classification is purely speculative”

I disagree and this is why:

Embryologists have described in detail the normal torsional changes that occur during embryogenesis that shape the limb bud into a supinatus position. And the normal torsional changes that occur during fetalgenesis that mold the foot from a supinatus structure to a plantargrade structure. This torsional unwinding is always linear, proximal to distal (femur to foot).

Let’s follow this step by step in the developing foot:

• First the cuboid unwinds (taking with it, the lateral column of the foot), from supinatus to plantargrade (plantar surface perpendicular to the leg).

• After the calcaneus has completed its positional migration on top of the talus, it starts unwinding, from supinatus to plantargrade.

• And the finally, after the calcaneus has nearly completed its’ torsional unwinding, the talus inchoates its’ torsional development, and with it, the entire medial column of the foot.

If we were to look inside the womb and watch this process in real time, this is what we would see:

• At approximately Week 10pf, we would observe an embryonic foot structure that resembles a clubfoot deformity. That is, both the calcaneus and talus (including the medial column of the foot) would be in supinatus. If this structure was retained (e.g., the calcaneal ontogenetic development prematurely ended at this stage), at birth the baby would be diagnosed as having a clubfoot deformity, a very obvious foot deformity.

• At approximately Week 11pf, as the foot continues to unwind, we would observe an embryonic foot structure that resembles the PCFD. If this structure was retained (e.g., the calcaneal ontogenetic development prematurely ended at this stage), the infant would be diagnosed as having the PCFD. Before age 4, this diagnosis is difficult to make due to the baby’s prominent fat pad.

• At approximately Week 12pf, as the foot continues it unwinding, we would observe an embryonic foot that resembles the RFS. If this structure was retained (e.g., the talar ontogenetic development prematurely ended), the infant would be diagnosed as having RFS. Again, before age 4 (there abouts), this diagnosis is difficult to make due to the baby’s prominent fat pad.

• At Week 36pf, the foot's torsional development has nearly completed. The heel and sole are plantargrade to the Ieg. In the neonatal, I refer to this foot structure as plantargrade.

So, In summation, With the above understanding, I contend:

• If the normal ontogenetic foot development is interrupted at approximately Week 10pf, the baby is born with a Clubfoot Deformity.

• If the normal ontogenetic foot development is interrupted at approximately Week 11pf, the baby is born with a PCFD.

• If the normal ontogenetic foot development is interrupted at approximately Week 12pf, the baby is born with a RFS.

 

Who is Gerald ? If you mean me, please see the signature at the end of this post .

My understanding is that club foot deformity is not classified until after birth when measurements can be taken .
There would seem to be nothing to be gained by classifying the condition before then or indeed , trying to classify similar but lesser developmental problems before the baby is born .

 

I agree. A clubfoot deformity is usually diagnosed immediately after birth.

 

You have not given me a reason to think that your foot types are different and you have a history of renaming concepts.

This is where your physics phobia gets you into trouble. Gravity drive and hip drive are descriptions of where the forces come from. You are trying to use force and moments without understanding force and moments.

From your post #30

Uncompensated: foot maintained in STJnp weight bearing (positioned by examiner)
Compensated: relative to RFS and PreClinical Clubfoot Deformity - pronated

from your post #19
The PreClinical Clubfoot Deformity is a congenital deformity involving both the calcaneus and entire embryological medial column of the foot, both being in supinatus.

• Calcaneal supinatus is a structural twist (transverse axis) within the bone. Relative to the ground (uncompensated, standing) it would be twisted so that the medial plantar surface would be elevated, apex (highest) medially, tapering to nothing laterally.

• Medial column supinatus is a structural twist involving the talar head and neck, navicular, medial cuneiform, 1st metatarsal (only) and hallux. Relative to the ground (uncompensated, standing), the 1st metatarsal and hallux only would be inverted and elevated relative to the ground, the apex of the
  
• elevation being medially, and tapering laterally. (The proximal supinatus being obfuscated by the contour of the ILA)

Your comments in post #30 were in response to the question what is uncompensated standing.

Your "deformities" are based on neutral position just as Root's deformities are.

Why did you use neutral position as a reference point for defining a deformity?

 

The embryological foot types are derived from the understanding on how the foot developes during gestation. They are not based on a neutral position.

 

When a patient walks in to your office you don't know what happened in utero until you put them into neutral position. Therefore, you are using neutral position to determine the foot type, just as Root did.

What happened in utero may determine the shape of the foot. But it is the shape of the foot that determines the mechanics of the foot. You are claiming that a certain foot type has gravity drive pronation because of its shape. You don't really have to know what happened in utero you only need to know the shape of the foot.

The term gravity drive pronation is an attempt at explaining why a motion occurs. Brian the science of explaining why motion occurs uses fores and moments. Your original post in this thread was anti science. The term gravity drive pronation means nothing unless you can use forces and moments to explain what it is.

 

Eric,

Below I have addressed your comments and hopefully answered your questions.

Initially, when a patient walks into my office, I take a complete history that includes a replete listing of the patient’s subjective symptoms.

In my practice I treat chronic musculoskeletal pain resulting from one of the embryological foot types, only. If the patient's subjective pain profile falls outside my diagnostic parameters, I refer them to someone who handles their specific problem(s).

Differential Diagnosis

20 years ago I advocated using the PMSv test to determine which embryological foot structure is present and its’ severity. This test uses the concept of STJnp and is described in my 2002 paper.

However, for the past 10 years, I have discarded this test due to the difficulty in accurately measuring PMSv with microwedges. Instead, I now use the Knee Bend Test and Gait Analyses to qualitatively differentiate which embryological foot deformity is present.

Quantitative Analysis

Running a computerized sagittal plane postural analyses, determines the strength of the proprioceptive signal to be incorporated into the insole. Some practitioners, who are comfortable with muscle testing, will use kinesthetic tests (e.g., Leg Rotation Test) and various other muscle testing techniques to quantify the severity of the deformation and determine the Rx.

As you can see, the above provas (tests) do not use the concept of neutral position (as Root did in his methodology).

Importance of understanding the ontogenetic torsional development of the foot

Knowing what happens during gestational development, defines the most common foot deformations that can occur postnatally. And with this understanding, it facilitates the process of differential diagnosis and intervention.

I agree with you that “motion occurs us(ing) forces and moments”. And it is gravity that drives that motion. And yes, you can enter into a replete scrutiny discussing these forces and moments involved in gravity drive pronation.

But clinically, the tests that have been developed to diagnose and treat RFS or PCFD do not require the analyses of these forces and moments. However, in research, the physics of these forces and moments should be considered and become paramount and decisive.

• Rothbart BA, 2002. Medial Column Foot Systems: An Innovative Tool for Improving Posture. Journal of Bodywork and Movement Therapies (6)1:37-46

 

Brian, you are intellectually dishonest. Earlier in this thread you told me to go read your paper (post #27). Now you say that you have discarded that. You have proven there is no point in arguing with you.

 

Eric,

Replacing the PMSv test (introduced 20 years ago), with a more reliable CPA, is what you consider being "intellectually dishonest", then so be it.

And, just so there is no misunderstanding, we are not arguing. Hopefully, we are exchanging ideas, points of view. Nothing more, nothing less.

 

No, the intellectual dishonesty was referring me to an article to read about your current thoughts that did not contain your current thoughts. Intellectual dishonesty is claiming that an article has certain information when it does not.

 

Eric,

Obviously there was a misunderstanding/miscommunication. The reason I suggested you read my 2002 paper was to elucidate exactly why the PCFD was not simply a renamed Rearfoot Varum, by reviewing the ontogenetic torsional development of the foot during fetalgenesis, and nothing more.

To be precise, below is exactly what I wrote in my prior comments:

(1) If you had read my paper (see above), it goes into the embryological ontogenetic development of the fetus during the first trimester. It explains exactly what the PreClinical Clubfoot Deformity is. And it is totally different from what Root labeled Forefoot Varum.

I have a suggestion, read my paper. And then let's discuss this in detail.

(2) If you want a complete presentation on PCFD I suggest you read:

• Rothbart BA, 2002. Medial Column Foot Systems: An Innovative Tool for Improving Posture. Journal of Bodywork and Movement Therapies (6)1:37-46

​

I did not suggest you read my paper to garnish an understanding of the PMSv test, which I no longer use. As you can see, No “intellectual dishonesty” intended.

Just a further clarification:

The practice of medicine is progressive, not static. That is, we are always improving on our skills in diagnose and intervention. Replacing the PMSv test with CPA is just an example of the former.

 

Please would you point me towards where I can read about these in a referreed biological journal. Ta

 

Rob,

The embryological foot classification is a result of my research. The PCFD and RFS were first brought to light in 2002 (Rothbart), a referreed journal.

Current interest in RFS:

• A research team in Iran (Zahra Safaeepour PhD) did several studies on the RFS

• Renee S Hartz MD and Mary Biancalana MA, CMT, Journal of Pain) published a clinical study (n=214) on patients Dx with RFS

The interest in my research has been exponentially increasing. According to ResearchGate.net, my research has garnished the following interest as of November 17, 2021:

• 158.5
  Research Interest - Interest on my original research is higher than 72% of researchers on ResearchGate.
• 196
  Citations
  
• 35
  Recommendations
• 14,296
  Reads
• RG Score 15.76 - My score is higher than 62.5% of all ResearchGate members’ scores.

The RG Score is calculated based on the research in my profile and how other researchers interact with my content.

 

I did not see anything in your paper that differentiated your foot types from Root et al's foot types. This is why I had asked you to cut and paste the information where you thought it was different. Claiming information is in a paper when it is not is intellectually dishonest.

 

Brian, you are coining a term that should use physics to explain what it is. Yet, in this thread you were critical of the overcomplication of biomechanics with the use of the terms force and moments. Brian you have introduced the term gravity drive pronation without a way of understanding what the term means. If you cannot define gravity drive pronation in terms of forces and moments there is no reason for you, or others, to use the concept.

 

Brian ,

Whilst it seems to me you are no stranger to a tall tale or two ( Golds Gym and all lifting new PBs with insoles from your bag ) , you do seem to have been the first to to place wedges under the big toe with a view to earlier proprioceptive input from the intrinsics during gait ,possibly giving earlier activation of the intrinsics and thus controlling pronation .

That being the case fair play ,but, IMO, your classification system cannot be supported without evidence directly linking measurable abnormality of the foot at birth with "your" foot types in adulthood .

 

When I first described the proprioceptive insoles I invented, on this forum, you should go back and read the vitriolic comments:
One of our esteemed colleagues vehemently stated: "You are destroying the 1st MPJ by placing a wedge underneath the 1st metatarsal" Subsequent research supported my original research and proved that protestation unfounded. (Aminian, Safaeepour et al 2012).

And in fact, this was not an isolated occurrence.

In 1988 I published a statistical paper linking abnormal (gravity drive) pronation to disruptions in the sagittal and frontal plane motion of the pelvis. At that time, the acidic remarks flinged in my direction were astounding. In posterity, that paper has been cited innumerable times. And if you do a Google search on that link, you will find that it has been validated by many other research teams.

I could provide many more examples, but I do not want to belabor the point.

You commented: "IMO, your classification system cannot be supported without evidence directly linking measurable abnormality of the foot at birth with "your" foot types in adulthood"

I believe I have done so. Case in point, fetal foot at 10week pf vs Clubfoot deformity at birth. Both identical foot structures. Fetal Xrays have been taken (which I had on my research website) demonstrating this.

But as they, "That's what makes horse racing, different strokes for different folks"

• Aminian G, Safaeepour Z et.al.2012. The effect of prefabricated and proprioceptive foot orthoses on plantar pressure distribution in patients with flexible flatfoot during walking. Prosthetics and Orthotics International DOI:10.1177/0309364612461167

• Rothbart BA, Esterbrook L, 1988. Excessive Pronation: A Major Biomechanical Determinant in the Development of Chondromalacia and Pelvic Lists. Journal Manipulative Physiologic Therapeutics 11(5): 373-379.

 

That actually occurred, as fantastical as it may sound, that professional weight lifter increased his lift capacity by 50 lbs with the simple application of forces and moments. Nothing new for the Russians, they have been doing this for years in the Olympics!

I am surprised no one has mentioned the link (I presented) between pregnancy and foot proprioception. Again, if you go back and read the comments, they were execrable. However, again as bizarre as it may sound, it is factual. The link is the posterior sagittal plane adjustment that occurs in the pelvis when gravity drive pronation is attenuated.

I clinically observed this connection in more than 10 of my patients during their RPTherapy. At the time I theorized that the posterior shift of the pelvis released the compression on the fallopian tubes, hence facilitating their impregnation.

Earlier this year, I read a research study where the same observation was made. I will see if I can find and cite it.

 

Not one lifter but eight from the audience . And no warm up . Yes it does sound fantastical .
Here is the quote
"Just an interesting anecdotal incident at Gold's Gym in St Petersburg Florida some years ago:

I was presenting a workshop for some 30 aspiring weight lifters at the Gym, discussing the concept of linear vs torsional mechanics: how torsional mechanics compromised performance

One weight lifter volunteered to be a test case:

• His best ever squat lift was 500 lbs.
• He proceeded to squat lift 485 lbs.
• Upon examination I diagnosed the PreClinical Clubfoot Deformity and concomitant gravity drive pronation (he functioned in extreme gravity drive pronation).
• I placed the appropriate Proprioceptive Insole inside his (new) shoes
• He proceeded to squat lift 540 lbs
• Removed the Proprioceptive Insoles, his squat lift fell to 485 lbs

This test was then repeated with 7 other lifters with the same results: decreasing the torsional mechanics resulting in increasing their lb performance.

Not definitive but certainly compelling. "

Are you sure it was ten and not just one or a coincidental two .

Anway , fluff aside and getting back to your classifications , a baby is diagnosed with club foot after it is born and the severity of the condition is classified by measurements .

Can your foot types be classified by measurement after birth and if not how do you know they are present ? Could you provide a link to a study that identifies your foot types at birth and then follows through to specific defects in later life .

Also with regard to gravity driven pronation and hip driven pronation , could you succinctly define these on these pages and highlight the differences ?

 

Hi Gerrad,

You asked: Can your foot types be classified by measurement after birth and if not how do you know they are present?

Neither the RFS nor the PCFD can be diagnosed at birth. The earliest a definitive diagnosis can be established is when the baby’s fat pad has diminished and their neurological system has completed its development.

The differential diagnosis is discussed in the following paper:

• Rothbart BA 2010. The Primus Metatarsus Supinatus (Rothbarts) Foot and the PreClinical Clubfoot Deformity.Podiatry Review, Vol. 67(1):

You asked: Also with regard to gravity driven pronation and hip driven pronation , could you succinctly define these on these pages and highlight the differences ?

Hip Drive:

The understanding of normal pronation is based on the work of Inman (Inman VT. The Joints of the Ankle. Williams and Wilkins, 1976) in which he couples subtalar pronation/supination to the horizontal plane oscillation of the pelvis:

Ambulation is an internal/external rotation of the pelvis around the weight bearing axis of the body. The total amount of this rotation varies from individual to individual. As the pelvis swings forward, the femur and tibia synchronously rotate internally.

• It is this internal shank rotation that generates STJ pronation at heel contact.

As the pelvis swings backwards, the femur and tibia synchronously rotate externally.

• It is this external shank rotation that generates STJ supination, initiating at flatfoot stance in gait.

This coupling of pronation/supination to internal/external horizontal plane rotations of the pelvis is referred to as Hip Drive. Transverse rotation of the innominates pronates and supinates the feet.

• Counter Clockwise rotation of the pelvis, pronates the right foot, or supinates the left foot in a closed kinetic chain.
• Clockwise rotation of the pelvis pronates the left foot, or supinates the right foot in a closed kinetic chain.

Gravity Drive:

If the subtalar joint's pronation/supination is decoupled from the horizontal plane rotations of the pelvis, it is referred to as Gravity Drive.

A common cause of gravity driven pronation is a structural deformation within the foot itself (e.g., Rothbarts Foot and/or PreClinical Clubfoot Deformity).

In Rothbarts Foot, at flatfoot (stance phase), the first metatarsal and hallux are not touching the ground.

As the forefoot is weighted, gravity forces the first metatarsal and hallux downwards until they rest on the ground (referred to as Gravity Drive Pronation)

This downward rotation of the first metatarsal and hallux forces the subtalar joint to pronate when it should be supinating.

 

Could you clarify what you mean by "and their neurological system has completed its development." ?

 

All the neurons in the cortex, temporal, parietal and frontal lobes are produced prenatally, however they are poorly connected. Most of the synaptic connections are produced after birth in a massive burst, aka exuberant period.

In the first 2-3 years of life, an astonishing two million new synapses form every second. These synapses control such areas as locomotion, hence the reason the toddler’s gait is so precarious early in life, and why we are unable to accurately access the infant’s gait until approximately 4 years of age when the synaptic connections are sufficient.

Gait analyses is one of the primary tests we use to differentiate a plantargrade foot from RFS and PCFD.

 

Primus Metatarsus Supinatus test (PMSv Test)

 

Gravity Drive (Abnormal) Pronation seen in RFS



At midstance the right foot is pronating (gravity drive pronation):

• The pelvis is rotating clockwise.

• This clockwise pelvic rotation should be supinating the right foot (e.g., hip drive supination)

 

RFS - Gait Correction (gravity drive pronation attenuated) using proprioceptive insoles (3.5mms)



Frames 1 and 3 - No Insoles

• Frame 1 - gravity drive pronation at midstance
• Frame 3 - gravity drive pronation at early heel lift

Frames 2 and 4 - with 3.5cmm Insoles

• Frame 2 - attenuation of gravity drive pronation at midstance
• Frame 4 - attenuation of gravity drive pronation at mid heel lift

 

Brian , just to be clear, are you saying that the foot types described by Root are not the "result embryological ontogenetic development of the fetus "?
If not what causes them ?

 

Any comments regarding the gait analyses I have provided above?

 

Embryologically, the foot types described by Root cannot occur because the ontogenetic development of the cuboid, calcaneus and talus are linearly sequenced.

 

Thank you for providing the information .

If you don't know what causes the foot types described by Root, how do you know they are different than yours ?

 

Are you still an advocate of Root's foot types?