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Kevin Kirby posted a while ago and listed his considerations of the various roles of the plantar fascia (10 I think). Search as I might I cannot find it
I don't think Kevin has posted them - we have mentioned them in other threads. Kevin has a lecture on the "Ten Functions of the Plantar Fascia" - he given it a few times including at the last years SMA conference here in Melbourne --- I followed it with the "Four Dysfunctions of the Windlass":
Quote:
1. No windlass
2. Delayed onset to windlass establishment
3. High force to establish the windlass
4. Disruption during loading of the windlass.
Maybe Kevin will list them...
__________________ Craig Payne
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Last edited by Admin : 3rd January 2006 at 02:18 AM.
Reason: added quotea
Kevin Kirby posted a while ago and listed his considerations of the various roles of the plantar fascia (10 I think). Search as I might I cannot find it
Can anyone suggest the post it is under? :)
Thanks
Ian
Ian and Craig:
Here is my current list of the functions of the plantar fascia:
1. Serves to support the medial and lateral longitudinal arch in a higher arched position (i.e. increases the dorsiflexion stiffness of the medial and lateral forefoot)
2. Assists in resupination of subtalar joint (STJ) during propulsive phase of walking
3. Assists the deep posterior compartment muscles by limiting STJ pronation
4. Assists the plantar intrinsic muscles in preventing longitudinal arch flattening
5. Reduces tensile forces in plantar ligaments
6. Prevents excessive interosseous compression forces on dorsal aspects of midfoot joints
7. Prevents excessive dorsiflexion bending moments on metatarsals
8. Passively maintains digital purchase and stabilizes proximal phalanx of digits within sagittal plane
9. Reduces ground reaction force on metatarsal heads during late midstance and propulsion
10. Helps to absorb and release elastic strain energy during running and jumping activities
Most of these functions are now supported by research while some of them are based only on my consideration of mechanical modelling of the foot.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
BACKGROUND: Plantar fasciotomy, a common operative procedure to relieve chronic heel pain, has been suggested to decrease foot arch stability. A systematic evaluation of the biomechanical consequences of partial or total plantar fascia release is essential to the understanding of the biomechanical rationale behind these operative procedures.
METHODS: A geometrical detailed three-dimensional (3-D) finite element (FE) model of the human foot and ankle, incorporating geometrical and contact nonlinearities, was constructed by 3-D reconstruction of MR images. Partial and complete plantar fascia releases were simulated to evaluate the corresponding biomechanical effects on load distribution of the bony, ligamentous, and encapsulated soft-tissue structures.
RESULTS: Partial and total plantar fascia release may decrease arch height but did not necessarily cause total collapse of the foot arch even with additional dissection of the long plantar ligament. Operative release of the plantar fascia was compromised by increased strains of the plantar ligaments and intensified stress in the midfoot and metatarsal bones. Load redistribution among the centralized metatarsal bones and focal stress relief at the calcaneal insertion were predicted with different types of fasciotomy.
CONCLUSIONS: The FE model suggested that plantar fascia release may provide relief of focal stress and therefore could relieve associated heel pain. However, these operative procedures may pose a risk to arch stability and clinically may produce dorsolateral midfoot pain. The initial strategy for treating plantar fasciitis should be nonoperative. If surgery is necessary, partial release of less than 40% of the fascia is recommended to minimize the effect on arch instability and maintain normal foot biomechanics.
RESULTS: Partial and total plantar fascia release may decrease arch height but did not necessarily cause total collapse of the foot arch even with additional dissection of the long plantar ligament.
From the Ten Functions of Plantar Fascia:
1. Serves to support the medial and lateral longitudinal arch in a higher arched position (i.e. increases the dorsiflexion stiffness of the medial and lateral forefoot)
Quote:
Operative release of the plantar fascia was compromised by increased strains of the plantar ligaments and intensified stress in the midfoot and metatarsal bones.
5. Reduces tensile forces in plantar ligaments
6. Prevents excessive interosseous compression forces on dorsal aspects of midfoot joints
7. Prevents excessive dorsiflexion bending moments on metatarsals
Hopefully the physicians that perform plantar fasciotomy without understanding its important multiple mechanical functions in the human foot will eventually come to realize that the sole function of the plantar fascia is not simply to cause chronic plantar heel pain.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
One word, redundancy. Mechanical redundancy occurs when there is more than one structure that can support load. When one structure is removed the other structures will have to support more load.
Re: Functions and Dysfunctions of the Plantar Fascia
Quote:
Originally Posted by Kevin Kirby
Ian and Craig:
Here is my current list of the functions of the plantar fascia:
1. Serves to support the medial and lateral longitudinal arch in a higher arched position (i.e. increases the dorsiflexion stiffness of the medial and lateral forefoot)
2. Assists in resupination of subtalar joint (STJ) during propulsive phase of walking
3. Assists the deep posterior compartment muscles by limiting STJ pronation
4. Assists the plantar intrinsic muscles in preventing longitudinal arch flattening
5. Reduces tensile forces in plantar ligaments
6. Prevents excessive interosseous compression forces on dorsal aspects of midfoot joints
7. Prevents excessive dorsiflexion bending moments on metatarsals
8. Passively maintains digital purchase and stabilizes proximal phalanx of digits within sagittal plane
9. Reduces ground reaction force on metatarsal heads during late midstance and propulsion
10. Helps to absorb and release elastic strain energy during running and jumping activities
Most of these functions are now supported by research while some of them are based only on my consideration of mechanical modelling of the foot.
Dr Sha adds an 11th and 12th for consideration (based only on my consideration of mechanical modelling of the foot---) :
11. Provides stability and a functional lever arm to allow the extrinsic and intrinsic muscle engines that power the rearfoot and forefoot to perform more efficiently and effective.
12. Reduces the peroneus longus from acting as a rearfoot pronator in stance and gait. peronealTendonsPlantar1.gif
Re: Functions and Dysfunctions of the Plantar Fascia
Quote:
Originally Posted by drsha
Dr Sha adds an 11th and 12th for consideration (based only on my consideration of mechanical modelling of the foot---) :
11. Provides stability and a functional lever arm to allow the extrinsic and intrinsic muscle engines that power the rearfoot and forefoot to perform more efficiently and effective.
12. Reduces the peroneus longus from acting as a rearfoot pronator in stance and gait.
Hi Dennis,
Welcome back.
I was wondering why you felt your additions were different from
Quote:
1. Serves to support the medial and lateral longitudinal arch in a higher arched position (i.e. increases the dorsiflexion stiffness of the medial and lateral forefoot)
2. Assists in resupination of subtalar joint (STJ) during propulsive phase of walking
11 and 1 seem to be the same in that they both seem to be addressing stiffness of the foot
12 and 2 seem the same in that they could be interpreted to mean increase supination moment at the STJ.
Re: Functions and Dysfunctions of the Plantar Fascia
[quote=efuller;
11 and 1 seem to be the same in that they both seem to be addressing stiffness of the foot
12 and 2 seem the same in that they could be interpreted to mean increase supination moment at the STJ.
Regards,
Eric[/QUOTE]
Eric:
Back? I never left!
#1 makes no mention of the plantar fascia stabilizing the rearfoot (it mentions the medial and lateral forefoot) so perhaps I should have restricted #11 to say
Provides stability and a functional lever arm to allow the extrinsic and intrinsic muscle engines that power the rearfoot to perform more efficiently and effective.
But at that point, referring to gait, #11 would have to be #1.
#2 discusses activity during the propulsive phase of gait.
I think that the contact phase going to midstance are the additional phases of gait that I am referring to (adding as # 12). Since peroneus, in open chain, is a pronator of the foot, it must be restricted before propulsion in order to have a locked and efficient foot when necessary in function and to allow it to have reserves to perform midstance and beyond.
Dennis
PS:
Robert, I want my diploma!
I'd hang it up in my office in a supination moment.
Functions and Dysfunctions of the Plantar Fascia
Re: Functions and Dysfunctions of the Plantar Fascia
Linear Mode
