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Five toed windlass

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Simon Spooner, Mar 28, 2012.

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    All, during my lecture on myth busting in biomechanics last week in Belgium (available here: http://www.arteveldehogeschool.be/e...iatric Biomechanics myth busting. Belgium.pdf ) I talked about Hicks's description of the windlass mechanism:

    Hicks stated that: “When one toe alone was extended the corresponding metatarsal head was found to be moved by the mechanism posteriorly and downwards...
    Although this mechanism exists in each of the five rays it’s effects are most marked in the first ray. Thus, when all toes are equally extended, the first ray shows the greatest degree of flexion and the fifth the least. This is a pronation twist of the forefoot.”

    Hicks J.H.: The mechanics of the foot ii. The plantar aponeurosis and the arch.
    Journal of Anatomy vol. 88 part 1

    The presumption and modern interpretation seemingly being that each toe extends (dorsiflexes) by the same number of degrees during gait, and at the same time. In reality, the degree of dorsiflexion in each digit should be variable and phasic during gait. So where does this assumption that the windlass mechanism of the foot should result in a "pronation twist of the forefoot" during gait come from? My guess: a misinterpretation of Hicks.

    Lets say the digits all dorsiflex simultaneously but by varying degrees- should we still expect to see a "pronation twist of the forefoot"- not necessarily. If the digits are each dorsiflexing by varying amounts: 5>4>3>2>1 then this could result in a supination twist of the forefoot, or no twist of the forefoot- right?

    What influence does the variation in toe length have?

    If phasic extension of the toes runs from the 5th toe through to the 1st, what influence should this have?

    What influence might a tear in the plantar plate have?
  2. Let me put it another way, since despite over a hundred views no-one has responded. Why do you assume that the windlass function of the foot should result in resupination of the rearfoot when you have no idea of the number of degrees of dorsiflexion occurring in the lesser digits during gait, nor of the timings of the extension of each digit relative to one-another?

    "Errrr because the windlass mechanism causes resupination" Oh yeah? Who says?

    Bojsen-Moller anyone?
  3. BTW resupination can only occur if the net supination moment is greater than the net pronation moment. But does the lesser toes windlass action add to the net supination moment or, does it decrease the net supination moment?
  4. efuller

    efuller MVP

    When you take a cadaver rearfoot and push proximally on the talar head and pull anteriorly on the attachment of the plantar fascia you get supination of the STJ. Some cadavers are easier than others. Unbpublished research of mine.

    I think part of your question is related to the relative amount of metatasal motion as you go from medial to lateral. The original question talked about pronation of the forefoot. So, if the medial metatarsals plantar flexed more than the lateral metatarsals then it would appear as eversion of the forefoot. I think that explains the Hicks quote regarding the forefoot motion. Eversion of the forefoot is not necessarily what causes rearfoot supination. I believe it is the forces created in the first ray windlass that cause resupination as described in my windlass paper. Those forces are the posterior push from the navicular on the talar head and the anterior pull on the calcaneus at the attachment of the plantar fascia.

    There are some other factors that will also be important. Since the first ray plantar flexes more than the other rays, we might be able to assume that there would be a medial shift in the center of pressure on the forefoot and this will tend to reduce the pronation moment from the ground. Another factor that might be relevant is that the bases of the medial metatarsals are higher off of the ground than the lateral metarsals, so that the slip of the plantar fascia to the respective toe will have a longer lever arm to cause plantar flexion of the metatarsal in the medial rays. Also, I recollect from Sarafian that sometimes there is no slip to the 5th toe as it goes to the base of the metatarsal.

  5. Thanks for your reply Eric.

    Firstly, I agree regarding anatomical variation of the insertion of the plantar fascia into the 5th toe.

    My contention here is really regarding the degree and timing of dorsiflexion of each digit during gait. The observation of Hicks being that with equal amounts of digital dorsiflexion, the first ray plantarflexes (due to the windlass mechanism) more than the other rays. Yet, if at a given instant in time during gait: the fifth toe were to be dorsiflexed by say 70 degrees; the fourth toe by 65 degrees, the third toe were dorsiflexed by 50 degrees, the second by 40 degrees and the hallux by 30 degrees, would the foot's windlass mechanism still be producing supination moment, or would it be producing pronation moment?

    We don't know what the exact number of degrees of dorsiflexion of each digit should be required to have the same amount of ray plantarflexion in all rays, so the numbers above are somewhat arbitrary. But lets pretend that the degrees of digital dorsiflexion I gave above result in exactly the same amount of ray plantarflexion in all rays. Would you still expect eversion of the forefoot? Then pretend that the numbers I gave for digital dorsiflexion result in plantarflexion of the rays such that the 5th ray plantarflexes > 4th> 3rd>2nd>1st; are we still going to get forefoot eversion?

    The forefoot "pronation twist" described by Hicks was dependent upon all digits being dorsiflexed by the same amount, at the same time. I don't believe this situation exists for more than an instant, if at all, during the propulsive phase of gait.

    Let me put it another way: if we dorsiflex the 4th and 5th toes in isolation, would the windlass effect from this result in forefoot inversion or eversion? What factors define this effect?
  6. Kenva

    Kenva Active Member

    Hi Simon

    Leaving aside the equal amount of DF of the digits, I understood from this description that the largest windlass was the one around the 1st metatarsal head making a relative more plantar flexion moment of the first ray compared with the lesser metatarsals. if you would look at the forefoot alone - one could easily define a relative forefoot 'pronatus'
    The biggest misinterpretation in my opinion is that the forefoot during propulsion is the fixed segment of the foot making contact with the ground. The heel begin lifted of the ground and being able to start an inversion movement.

    For this to be true, a couple of parameters need to be defined?
    What's the length of the plantar aponeurosis going to each digit?
    What's the diameter of each metatarsal head?
    How far (distal) on each digit does the PA end?
    Does every toe equally DF.

    Assume that the length of all segments of the PA are the same, the amount of DF of each toe is the same,... The effect would be only dependent on the size of the metatarsal head, and this is the Hick's assumption.
    The question is, (if you have a 80° DF of D5, 70° of D4 etc. ) when do you reach a net result of equal windlass effect on MTP 5 and MTP1
    in other words, how much DF in D5 do you need to equal out the inversion/eversion effect of the PA on the rear foot, when the hallux dorsifexes ie. 10°...

    Not sure i'm making myself clear here...
  7. Ken, I think you've defined the variables quite well... Yet we have not quantified the variables. Here's a simple one which should have been done- what is the average dorsiflexion of each of the toes during walking? You'll find lots of data for the hallux, but virtually nothing on the lesser digits. Here's another, what is the phasic relationship of dorsiflexion in the digits? What is the average sagittal plane radius of each of the metatarsal heads... etc.

    There's your next project.

    p.s. try the Spooner test: dorsifex each of the digits in turn, see if you get internal or external rotation of the leg, see if you get pronation or supination of the foot when each digit is dorsiflexed. This might give you an indication of what each digital slip is bringing to the party.
  8. efuller

    efuller MVP

    When you have long gear pushoff (I don't like that term, but everyone seems to know it.) , when looking from behind, you can often see the 5th toe not touching the ground when the first met and hallux are both still on the ground. Certainly in this position, the slip of the fascia to 4 and 5 don't matter.

    In some feet, where the 5th met is considerably shorter than the 2nd, there would have to be quite a bit of STJ supination to keep the 5th met on the ground during push off.

    Thinking about the retrograde force on the metatarsals, when you push the anterior facet posteriorly, you will tend to get pronation of the STJ. Now, thinking about it I don't recall pulling anteriorly at the fascial attachment at the same time. If you hold the talus steady and push posteriorly on the anterior facet of the calcaneus the STJ will pronate. I'm not so sure what would happen if you simultaneously pushed from ant to posterior on the anterior facet, while simultaneously pulling anteriorly on the attachment of the plantar fascia.

    Again, I think the motions seen with activation of the windlass are not caused by a rotation of the forefoot relative to the rearfoot, but rather the more proximal pushes and pulls. If you want to give a function of the fascia that goes to the lateral rays, I would say that the big one is creating a plantar flexion moment on the ray that helps resist the dorsiflexion moment from ground reaction force.

  9. Athol Thomson

    Athol Thomson Active Member

    I think the other variable worth considering is whether all slips of the plantar aponeurosis are capable of storing and releasing the same amount of elastic strain energy. I doubt the slip to the 5th Metatarsal/digit will have the exact same extracellular matrix and collagen profile as say the slip to the hallux.

    The slip that is exposed to the greatest amount of loading during either windlass or reverse windlass loading should store the most elastic strain energy. Some of this energy is transduced directly into extracellular matrix and protein/collagen synthesis changes via mechanotransduction. With the majority of the energy returned to the system to create movement.

    Pretty thought provoking subject Spooners five toed windlass......I haven't been able to get it out of my head for 24 hrs now....Thanks for that Simon!

  10. It's not mine.... Hicks described it.

    I think it was Pollard when looking at shear forces who said the fifth ray had little, if any role in propulsion, Eric. I tend to agree there.

    Bed now though. I'll give it some more thought over-night.
  11. drsha

    drsha Banned

    Correct me if I'm mistaken but you seem to be stating that focusing on the first ray (The MLA) is a mistake and that we must look at all five rays when it comes to the windlass effect (The Vault of The Foot).

    Firstly, I thought that structure (Architecture) played little to no role in biomechanics?

    Second, I thought that Shavelson's Vault of The Foot had little import to Spooner et al?


    Attached Files:

  12. Kenva

    Kenva Active Member

    I'm not sure the discussion here is about being wrong thinking that the first ray is important when looking at the windlass mechanism. The discourse here is trying to understand the roll of the lesser digits in the windlass mechanism

    Be careful here drsha. In my opinion, one of the most thoroughly accepted principles of modern biology is that form is unarguably related to function BUT function is not per sé exactly te same as biomechanics. In human locomotion there are much more influencing parameters determining function then only the structure of the foot. The foot and the digits changed in shape during evolution. And if I understood the lecture of Dr. D'Août correctly, shape rather changed to perform better function, then the other way around.
  13. drsha

    drsha Banned

    Good research person:
    Are you the judge of what this discussion is about?
    Why wouldn't my comment be a part of the discussion?
    Dr Spooner discusses one toe Hicks (MLA) and then five toe Hicks (The Vault) and the Topic is The Five Toed Windlass is it not?

    Good research person:
    Is this a threat?

    I do agree strongly with this statement.
    I therefore question:
    Then if the structure of the foot is one of the influencing parameters in determining structure, then why should we eliminate architecture from biomechanics or this discussion?

    Rephrasing in order to be careful here:
    When dealing with the five toed windlass, are we dealing with The Medial Pedal Arch or The Vault of The Foot Architecturally?

  14. RobinP

    RobinP Well-Known Member

    I love podiatry Arena for the threads like this that challenge some conventional thinking and make the lazy people like me think about biomechanics in a fashion well beyond my usual capabilities

    However, when I go on to the new thread page, 2 things jump out at me

    1. barefoot running
    2. drsha has replied to many of the threads and, unfortunately, the threads degenerate into a slanging match about foot typing and architecture. Also unfortunately(and i am trying to say this without coming off as being a bully) Dennis' insistence on peddling his own system and nomenclature simply diverts threads to pointless arguements.

    Other posters also frequently meintion their own paradigms but they are generally backed up by some peer reviewed literature that I can read about and decide for myself so this is far less offensive. Their varied views on things also serve to make them look less like one trick ponies

    Not that my contributions to this forum are innovative or even, for that matter, interesting but I am rapidly going off pod arena for these reasons which is a shame

    Dennis, please can you have a little perspective on this. I don't appreciate a continuous barrage of religious Dogma being shoved down my throat and i feel the same about my biomechanics.

    Simon, good thread. My opinion, for what it is worth is that there must be a constantly changing net effect depending on met length, toe length, plantar aponeurosis tension and anatomy, proximal anatomical variations with respect to overall rotational amount versus line of progression. Also, i'm sure the elastic strain potential that Athol mentions has something to do with it but that is waaaaaayyyyy beyond me at the moment

    The idea that the foot should resupinate at a particular point otherwise the foot is not functioning properly seems flawed based on this.

  15. Kenva

    Kenva Active Member

    No threat from my part - and no personal attack eighter. Just trying to point to the fact that there could be a mistake in judgement if you only put form before function and if you redefine function as biomechanics. I'm not the judge here, and i'm not the one making statements here eighter.

    Also, sorry for my ignorance, but i don't know the vault of the foot. Never came across this term in the literature before - have to read more literature I suppose. the medial pedal arch, if you mean that this is an arch created if the lateral part of the plantar fascia is brought under tension, could exsist.

    I just don't see the one on one connection you make with the five toed windlass and the lateral arch architecture.

    What do you mean?
    There is a lateral arch, therefor there exsists a windlass mechanism around the 5th met head
    There could be a significant windlass mechanism around the fifth met. head, possibly creating a lateral arch.
  16. drsha

    drsha Banned

    I do too.
    That's why I participate Robin.
    Problem is I have the nerve to offer challenges to conventional thinking that do not totally conform to The Arena Agenda.
    I won't be bullied away or silenced especially because my following keeps growing elsewhere in spite of your personal attacks.
    Craig showing me as Bart at the nuclear plant in his lectures. Spooner putting me next to a picture of a dinosaur and calling my parents mutants are merely seeds you are planting to eliminate dissent in your ranks to no avail. The world is watching.
    You want to brainwash the students and those interested but less capable to your zealous biomechanical viewpoint.
    I have no problem with that until you make me out to be Satin.

    You state Architecture has no place in biomechanics because I preach it. Now Spooner has two threads, this one and the navicular height one that are Architectural. Not one of you ever will credit me with trying to keep structure alive as a vital part of biomechanics (Not even Jeff Root, the son of the architect of biomechanics).

    I visit foot typing, a concept that makes so much sense to so many wanting to learn biomechanics. it assists in understanding, teaching and presenting biomechanics in practice and you have allowed me to turn Foot Typing into the "F" word for three years on The Arena.

    All of you utilize STJ Neutral casting, yet all I get when I comment on the fact that we should be upgrading our shells to allow less use of ORF's and supply a starting platform for subgrouping feet into characteristic types what I get, fored from both barrels is Dennis, we utilize many casting types in practice which doesn't obviate the fact that your default cast is the one that you state you have no evidence for.

    Scherer's and Kirby's labs when called state they prefer a STJ Neutral cast, can you understand that denies them of their arrogance and pulpits! Fuller hates me every time he takes a subtalar neutral cast and we all know how often that is. Robin, you must hate me everytime you take one as well.

    You asked me to discuss topics other than foot typing, I have (have you read the recent Derm Thread?).
    I have gotten thanks from a number of practitioners for the advice I offered in response to their clinical queries.
    I lecture around the world and show slides of the brilliant men and women that live on the Arena and quote the additions they have made to the literature.

    Robin, I piss on you because you piss on me on The Arena and I won't stop until you do. Haven't I proven that yet. Act like children and so will I.

    First I was Rothbart, then Glaser, then ??? and now I'm Barefoot when in actuality, you all know I am one of you, but dissenting in some areas that are yet undefined in the literature.
    I patent, profit and entrepeneur, so did Bill Gates, Henry Ford and Jonas Salk. Get over it.

    Give me some props and watch what happens.
    Throw me a bone.
    Show me a crack in the door.

    Even as a charlatan, at least acknowledge that I'm a good one.

    Actually Robin, you are a bully and that's why you need the parenthetical comment.

    Have you ever witnessed what you (yes you) and so many others do on any thread that I start?
    I worked with Chiropractors twelve years ago. Shoot me.
    I have no evidence just like most of you (although you act as if you do).
    The Subtalar Axis Paper had THREE SUBJECTS and the author posting here is so obviously biased.
    You have no consensus on orthotics.
    Leave one or two of my threads alone and watch what will happen.

    Give me one or two that have entered The Arena in the last 3-5 years with dissenting views to The Arena that have survived or were fairly evaluated.
    Ask Bruce Williams and countless others how you treat opposing viewpoints like Dananberg's or Jeff on how you treat him or Dr Root.

    When I publish peer reviewed articles (and I'm close to the second and third), you will destroy them all with your bias while vaulting any peer reviewed literature in your camp with higher praise than it deserves, you watch.
    Kirby publishes in Podiatry Today or in his own self published world and you accept it as if it was JBJS. No bias there.

    Here, I can't agree with you more :rolleyes: (we both know you participate on a pretty high level but how does that feel?)

    No you're not but I bet you would win the beauty contest between us if it were held.

    Ditto! Ditto! Ditto!
    David Smith tried to sling your dogma on an American site and he left with his eyes looking down.
    Craig's two articles a year don't impress me and next year, you won't have many valuable additions one more time.
    Biomechanics is just not very evidentiary. Get over that one too.
    (At least Craig has the class to expose how he judges situations when there is no evidence available)

    Simon, good thread but let's face it, it is Architectural in nature.
    Acknowledge who The Architect is here on The Arena and watch what happens.

    My opinion is that you are examining the windlass in open chain and not considering the foot type specific collapse with the Truss-Tie Beam structure of the foot as a clinical factor when transposing your theory into something that is clinical.
    The bones are collapsing secondarily stretching the soft tissue tie beam, not the reverse.
    Clinically, when you dorsiflex the toes, you stretch the plantar plate and produce compensatory pathology. That's a no no for me in practice.

    You know me Simon, Dr Pronation bad, Supination Good (what crap) so what can I say about this:rolleyes:.

    Summarily, When what's good for the Goose is good for the Gander on The Arena, watch what happens
    or fall pray to those that wish me off The Arena and bury dissent with my banishment from your Kingdom.

  17. RobinP

    RobinP Well-Known Member

    No further questions, your honour
  18. Kenva

    Kenva Active Member

    Did some looking around on 'the vault topic'
    I start to understand where we are coming from...
  19. Robin:

    After reading his last posting, I think DrSha needs to start his own website so he won't be bothered by the rest of us.

    The new website should be called:

    Dennis Arena

    I'm sure it will be verrrrryyy popular....oh yeah.....:rolleyes:
  20. drsha

    drsha Banned


    If you have any further questions about The Vault of The Foot and its clinical applications in Functional Lower Extremity Biomechanics or how it relates to The Foot Centering Theory of Structure and Function, please raise them on The Vault of The Foot Thread that Dr Spooner authored or in order to reduce the slanging matches, do as others continue to do and raise them personally to me @ drsha@foothelpers.com.

  21. drsha

    drsha Banned

    You miss the main reason that I am a Veteran Member, just like most of you, here on The Arena.
    I wish to engage with some of the best minds in the world of biomechanics and exchange ideas and philosophies in order to grow our beloved science and take it forward from where Dr's Root, Dananberg, Kirby and Payne et al have brought us.

    Or do you have a different agenda?

    I love it here and am more and more comfortable:cool:.

  22. Dennis:

    The reason why I avoid responding to your postings and avoid trying to engage with you in discussion here is that you can't seem to get over the "me versus them" mentality, where nearly every posting is more about what you think about the rest of us here on Podiatry Arena and less about what you think. You continually "pick fights" here for no apparent reason other than to try and prove that others aren't as good as they may think they are.

    I don't believe you are evil or a bad person. I believe you care about your patients and greatly care about the direction your profession is going. However, I wish you could just offer your considerable wealth of knowledge here without always mentioning the names of the others here on Podiatry Arena and portraying them in a negative fashion.

    I think that will find that if you start being more of a model of respect for the others here on Podiatry Arena who are considered as experts on biomechanics, then you will, in turn, get the respect you want and deserve. I am willing to let our disagreements be like water under the bridge as long as you can keep to the discussion and not start making accusations against many of us. However, I do not have the time, patience or inclination to respond to you otherwise.
  23. drsha

    drsha Banned

    Are you trying to say that The Arena has no "me versus them" posture when it comes to those, in Robin's words, that "challenge conventional thinking" in different ways then its biomechanical experts?

    DITTO, DITTO, Big Time!!!
    But to Kenya's agreement, there are more than one way to skin the biomechanical cat.
    In medicine and science, one makes a working diagnosis but also keeps alive and entertains a differential diagnosis in case the diagnosis has flaws or holes or in fact is just plain wrong.
    Kevin, I wouldn't begin to ask where you think the flaws are in SALRE and TS and dare I say it, depending so strongly on EBM but just in case they might exist what are your
    biomechanical differential diagnoses ?
    I in turn wish you could just offer your considerable wealth of knowledge here without always mentioning my name here on Podiatry Arena and portraying it in a negative fashion

    I, like you, have a hard time of being a "model of respect" on command. I would rather keep the status quo.
    Once again, if that's your ultimatum, I am more comfortable with being disrespected.

    Ditto, Ditto, Ditto!
    I am willing to let our disagreements be like water under the bridge as long as you can keep to the discussion and not start making accusations against me.

    Over the years, I have learned to navigate in your world as my differential diagnosis to Foot Centering, I am a better EBMer and a better TSer.
    The Arena has taught me so much and I am so appreciative.
    However, unfortunately, I have still not found reasons to apply SALRE into my protocol as I am a centrist thinker and SALRE is too far to the rearfoot. I post possible flaws and holes in your work because it, like some of Root and Dananberg and Payne's work, like mine, must be questioned in order to grow. I do that after investigating it and more and more, I incorporate the STJ Axis into my work.

    I, like you, do not do well to ultimatums.

    I have already started to temper my personalizations and am focusing on our work even though your personalizations remain toxic.
    Puff Daddy stepping on **** has no place on The Arena, EVER!
    I will continue to temper them as you do in kind and I have no ultimatums for you, ever.

    Happily, I have a sense that you taking the time to discuss our future together rather than apart.
    Building a common ground instead of trenches will be a great day for biomechanics.
    IMHO Biomechanics needs us united, not divided.
  24. Dennis:

    Then you will continue to be disrespected here on Podiatry Arena since that seems to be your wish.

    Have a happy life....I am done responding directly to you.
  25. You, Shavelson, were not even close to being the first to using the term "vault" to define the medial longitudinal arch of the foot. As can be seen from this thread http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=54083
    Kapandji had already suggested that this term was somewhat archaic and flawed by 1971. It is an archaic term, much like calling the talus the astragalus, but if it helps... to attempt to defraud the public. But don't lets pretend that Shavelson invented this term, because he did not. Not even close. I should like to state for the record, that "Shavelson" should not be credited with the terminology: "vault of the foot". Now, it would be nice if Shavelson could publicly admit that he was not the first to use the term "vault of the foot" and withdraw his statements pertaining to "Shavelson's vault of the foot". This is like me claiming Spooners laws of motion and ignoring Newton who clearly had made these observations in published research prior to me. For the record, there is no such thing as "Shavelsons vault of the foot" since many authors had described this prior to Dennis Shavelson. An apology might be in order from Shavelson for pretending that he was the first to describe the foot's arch structure as a "vault". Frankly, I won't hold my breath, since his ego will not allow it.


    Yes we should look at the five rays in terms of the DYNAMIC, WEIGHTBEARING CONTRIBUTION to the foot's structure and function. I don't believe that anyone has ever said that structure is not important. I do believe that Shavelson was attempting to construct a straw man argument here. Regardless, it is true that the study of structure in isolation is pretty useless, as indeed is the study of forces in isolation. I re-iterate though, I know few people who believe that the study of one or the other in isolation is useful, with the exception of perhaps: Dennis Shavelson.

    I'll come back to rest tomorrow. Frankly, I feel sick just responding to Shavelson's egotistical nonsense. But we'll see how it goes.

    Don't reply Shavelson. I have absolutely no interest in your thoughts. I am merely responding because my name was used directly. Don't send me any more private messages either.
  26. blinda

    blinda MVP

    Not much of a discussion, yet. But, patience is my middle name.

  27. I thought your middle name was "Kenneth"?
    He was second author.
  28. blinda

    blinda MVP

    No, that`s yours :rolleyes:

    Yeah, I know he was second author. But, as he informed us that he was lecturing on the proposed re-classification recently, I assumed (one never should, I know) that he would be an authority on the subject.

    And, before you say it; Yep, he probably is the cats father.
  29. Tkemp

    Tkemp Active Member

    I'm personally impressed at the number of times the word "ditto" can be used in a thread!
    I'm going to throw away my Thesaurus and make it the word of the month! :D
  30. efuller

    efuller MVP

    No Dennis, He's worried about you making yourself look stupid.

    Dennis, who is trying to eliminate architecture? We are just keeping architecture in proper prospective.
  31. Isaacs was put in mind of this

  32. drsha

    drsha Banned

    I have been using and crediting Kapanzi's work and illustrations in my lectures for many years.
    I guess I left out the ;) when I keyboarded Shavelson's Vault of The Foot. Sorry.
    In reality an architectural vault exists when two longitudinal arches (the MLA and LLA in this case) are connected by a transverse roof (in this case the sum of all the transverse arches).
    It lives in between the MLA and the LLA and not at the rim of the MLA. It is not measured by Navicular Height.
    (see Kapanzi's Illustration)

    This reflects what I called fantasy and ignorant interpretation of my work that Dr Spooner seems obcessed with on another thread

    Is this your clever way of getting me to not reply to your posts?
    Myth: Dennis will listen to Simon's commands withput free thought.
    Myth: Dennis will listen to Simon's commands withput free thought.


    Attached Files:

  33. David Wedemeyer

    David Wedemeyer Well-Known Member

    Simon, I guess Dennis left out the ;) when he copyrighted Kapandji and others work as well (what's that term for presenting someone else's work as your own...?)


    Huh? How many transverse arches and please name them all, Hell, trademark them? ;) What is their orientation? Noooo a series of independent bones supported by soft tissues does not make a "roof". Do roofs have interlocking pieces separated by distance and allow movement between them? No. Do arches have interlocking pieces separated by distance and allow movement between them. No. "Architecture" is a redaction of the complexity of the midfoot and inapplicable to structures which produce motion eg. biostructures which exhibit these features eg. the human foot.
  34. Its called plagiarism. It's OK though because Shavelson has "been using and crediting Kapanzi's work and illustrations in his lectures for many years." I have no idea who this Kapanzi is though.

    Kapandji not Kapanzi.:bash:

    Anyway, I started a thread in which I wanted to discuss the dynamic motion of the foot which occurs due to the windlass mechanism and the phasic dorsiflexion of the five toes during the propulsive phase of gait. Does anyone actually have anything to say about this subject? When the moderators find time it might be helpful if the garbage can be removed from this thread since very little that has been written since Shavelson interjected has anything to do with the OP.
  35. drsha

    drsha Banned

  36. Little bit of pot / kettle?

    We were talking about the 5 toed windlass, (a dynamic structure). You kinda gatecrashed with your ideas about achitecture. So we talked achitecture. Now you're accusing David of being off topic when he does too and want to get back into talking Cogs (whatever that means in the foot, but it sure ain't architecture) and the ROMS of intrinsics (muscles don't have ROMS).

    Fact is Dennis, you did use the phrase "shavelsons Vault of the foot". You can say you were tongue in cheek, but it rather clearly did not come across that way. And you have said in the past

    Which sort of suggests likewise. And as for your typo, It does look a bit dodgy, that you claim to have many times credited the guy for coining the term... but then forget how to spell it. Twice. Badly. Doesn't help your case.

    Can I make a suggestion? What you've discussed here does not particularly relate to the OP. If you want to discuss the vault of the foot, bioarchitecture, or anything else, start a thread about those things. Or bump one of the many, many threads we've had here before. Unlike many of my colleagues, I do think you should be heard on this forum Dennis, but you have an unfortunate habit of derailing unrelated threads into one of your pet topics. You might get more interest if you keep them to threads where they are relevant.
  37. Does anyone have a reference to a study which has examined the dorsiflexion of the lesser toes during gait? I seem to recall such a study, but can't find the reference. I got a feeling the reference might be in a chapter in Valmassy, but my copy is at work and I'm at home right now. Anyone?
  38. Simon:

    Getting back to your original question, the central component of the plantar aponeurosis sends slips to the medial and lateral sesamoids and also to the plantar plates and onto the bases of proximal phalanges of the lesser digits. The slips to the hallux through the medial and lateral sesamoids have a much larger effect than do the slips to the lesser digits, but certainly there is some minor effect of a "lesser digit windlass" after heel off. The question is, how significant is the "lesser digit windlass" when the lesser metatarsal heads have such a small diameter when compared to the first metatarsal-sesamoid diameters?
  39. Depends on the degree of dorsiflexion occurring at any given toe, at any given time. Despite the smaller radius of the lesser metatarsal heads ("drums" of the windlass) if we "crank the handles" (toes) further there seems little reason why the overall net effect could not be the same.

    Here's a slightly different way I've been thinking about this. Lets say we model the plantar fascia as a spring system; lets say each slip of the plantar fascia to each of the digits is an individual spring. Then effectively the springs (digital slips) are basically in parallel so the overall stiffness of the plantar fascia is simply an additive of the stiffness of each slip-

    K = stiffness
    X = displacement
    F = force

    K fascia = Kslip1 + Kslip2 + Kslip3 + Kslip4 + Kslip5.

    Dorsiflexing the toes effectively loads each spring, so the force each slip adds will be: Ffascia= -Kslip1X1 + Kslip2X2 + Kslip3X3 + Kslip4X4 + Kslip5X5

    So, the overall force that the facia exerts at its calcaneal attachment should be the sum of the force in each slip. Thus, we can vary the forces from each slip, but still arrive at the same net fascial (windlass) force.

    I think there might be an error in my reasoning here. Your thoughts...

    Got it now- this is only good for elastic force, and not the windlass function per se- or is it??? ... like I said: your thoughts.
  40. Simon:

    The problem with this line of reasoning is that, during gait, the digits are all dorsiflexing a similar amount in unison during propulsion. Also, due to the larger radius of the first metatarsal-sesamoid "drum", by the time the hallux has dorsiflexed even the slightest degree, the position of the foot joints have changed which may affect the lesser digit "windlass" effects.

    One other factor, relative to the subtalar joint, is that the first ray windlass will have a potentially large supination effect since it lies at the medial perimeter of the forefoot, with a longer supination moment arm possible than any other metatarsal ray "windlass". Certainly this arrangement is one of the reasons why having a large diameter first metatarsal head-sesamoid unit is so important in contributing to normal function of the human foot and lower extremity during the latter half of stance phase of walking.

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