Tweet
Daniel,
I think some of the confusion lies in how we define the actions
occurring at synovial joints.
My preference is to specify a joint by locating its axis or axes of
rotation. (The exception is where the axes of rotation are arbitrary
and not anatomically determined , i.e. the gleno-humeral joint - that
is another topic for a later time). Then locate the lines of force /
action of all the muscles working / operating / passing the joint
(more specifically the axis / axes of rotation.
Another of our differences lies in the definition of the movements of
inversion/eversion and supination and pronation.
Simplistically ( or "simple mindedly" - your choice) in- and eversion
occurs about the axes specified by the articular surfaces of the talus
and calcaneous; and supination and pronation occurs about the second
order instantaneous or resulting axis of rotation of the midtarsal,
transverse tarsal or Chopart's joint.
I may be wrong but I think that some investigators "define" these two
terms as occurring about these two joints simulatneously.
I find it difficult understanding why it is necessary to mention that
"... is not pure to the anatomical sagittal plane."
I don't think it is advisable to make any generalization as to the
independance or dependance of two or more joints in a kinematic chain.
I do think it would be useful to consider that any contracting muscle
- concentric, eccentric and isometric, does have an effect on all
joints it works / crosses and not only during concentric contraction.
My two cents for whatever its worth! (Two Cents?)
Cheers
Al
quoting Daniel Cipriani :
> Hello Dr. Solimene,
>
> I do not disagree with your response...I was simply implying that to
> consider the action of the TA, one must consider all the joints it crosses,
> and not simply the ankle joint (dorsiflexion/plantarflexion)...and that if
> one is describing the inversion/eversion action, it is important to identify
> the joint at which this motion occurs. In the earlier discussion, it seemed
> that inversion and dorsiflexion were mentioned without indication of the
> joints involved in these motions (implying only movement at the ankle).
>
> And I agree that the anatomical plane of reference is troubling, given that
> ankle dorsiflexion is not pure to the anatomical sagittal plane.
>
> I also concur that the movement at the ankle joint is not independent of the
> subtalar joint, especially when we are describing a weight bearing action -
> I failed to differentiate between a weight bearing action vs. a non weight
> bearing action of the TA. Thank you for clarifying. Yes, most certainly,
> when a muscle actively shortens, it involves all the axes it crosses.
>
> Daniel
>
>
>
> Daniel Cipriani, PT, PhD
> School of Exercise and Nutritional Sciences
> San Diego State University
> 5500 Campanile Drive
> San Diego CA 92182-7251
> (office) 619.594.1922
> (lab) 619.594.5625
> (fax) 619.594.6553
> http://www-rohan.sdsu.edu/dept/ens/ens_web/faculty/cipriani.htm
>
> -----Original Message-----
> From: as572@columbia.edu [mailto:as572@columbia.edu]
> Sent: Friday, May 09, 2008 9:52 AM
> To: Daniel Cipriani
> Cc: BIOMCH-L@NIC.SURFNET.NL
> Subject: Re: [BIOMCH-L] Locating Tibialis Anterior tendon's actionlineusing
> MRI
>
>
> Dr. Cipriani,
>
> Actually the tendon of the TA crosses several joints on its way its
> distal attachment. I believe it is necessary to define the line of
> action relative to all the joints ( read - axes of rotation) it
> passes. A task I do not believe has been done to this time.
>
> It is questionable if the talo-crural joint and subtalar are truly
> independent. The line of action of a given muscle will "work" all
> the joints it passes.
>
> Firstly, I find it difficult to accept the notion / concept that two
> joints are independent when the movement occurring at these joints
> occurs in different planes.
>
> Secondly, the idea / notion that a description of movement depends
> upon the plane(s) in which that movement takes place is significant
> eludes me.
>
> I believe, from your statement, that our definitions of inversion and
> eversion are different. I don't understand the usage of your term "a
> frontal plane motion" Nor indeed the term "is nearly a sagittal plane
> motion " for the talo crural joint.
>
> My difficulty with the use of anatomical planes to describe motions is
> that it does not take into account for the range of movement and the
> repositioning of the involved joints. It is a static rather than a
> more dynamic and functional approach.
>
> It is my belief that the usage of anatomical planes to describe
> motions and movement unnecessarily complicates descriptions without
> adding any additional useful or functional information. I think it is
> clearer if one depends on body specific references rather than space
> reference terms.
>
> Dr. Alfonso Solimene
>
>
>
> Quoting Daniel Cipriani :
>
>> In response to the discussion on the line of action for the TA, it is
>> important to keep in mind that the TA works across two different joints,
> the
>> ankle joint and the subtalar joint, which are essentially independent.
>>
>> The ankle joint (talocural joint) and the subtalar joint...these two
> joints
>> are independent in that the ankle joint motion is nearly a sagittal plane
>> motion (dorsiflexion/plantarflexion) - keeping in mind that the
> orientation
>> of the axis of motion for the ankle joint is not purely a
> frontal-horizontal
>> orientation. And the subtalar joint motion is mainly of inversion/eversion
>> (a frontal plane motion), and its axis is not purely in the
>> sagittal-horizontal orientation. The line of action of the TA might be
>> described relative to the joint action of interest separately (ankle joint
>> and dorsiflexion/plantarflexion, and the subtalar joint
> inversion/eversion)
>>
>>
>> Daniel Cipriani, PT, PhD
>> School of Exercise and Nutritional Sciences
>> San Diego State University
>> 5500 Campanile Drive
>> San Diego CA 92182-7251
>> (office) 619.594.1922
>> (lab) 619.594.5625
>> (fax) 619.594.6553
>>
>>
>> -----Original Message-----
>> From: * Biomechanics and Movement Science listserver
>> [mailto:BIOMCH-L@NIC.SURFNET.NL] On Behalf Of Greiner Thomas
>> Sent: Thursday, May 08, 2008 10:43 AM
>> To: BIOMCH-L@NIC.SURFNET.NL
>> Subject: Re: [BIOMCH-L] Locating Tibialis Anterior tendon's action
> lineusing
>> MRI
>>
>> A few comments in response to my response on the tibialis anterior. I
>> think we are mostly in agreement, but perhaps talking past each other.
>>
>>
>> "1. The anatomical planes of reference are arbitrary.
>>
>> 2. The line of force or action of any muscle does / do not occur "along
>> an artificial, and arbitrary, geometry" - it occurs where it occurs AND
>> during the range of motion of the involved body segments the position of
>> the line of action of a muscle continuously changes."
>>
>> This was my point exactly, although perhaps you say it better. The
>> anatomical planes are artificial and arbitrary and if you limit your
>> investigation to those planes you should not be surprised that muscle's
>> action line has an oblique orientation.
>>
>> "4. I respectful disagree that the line of action need be in the
>> sagittal plane to obtain meaningful data. It is done mathematically."
>>
>> I agree completely. This is a consequence that a muscle's force of
>> action "occurs where it occurs." That, is another way of saying that you
>> should not expect of find anatomical evidence of a muscular action line
>> if you limit your investigation to a single anatomical plane.
>> Investigations in three dimensions may eventually allow you to resolve
>> an action line to a particular plane, but before you can do that math
>> you need to know what the muscle does when it does something. Inasmuch
>> as Tibialis Anterior is a dorisflexor and an inverter (or perhaps
>> sometimes and everter) the line of action of its insertion tendon will
>> lie oblique to the sagittal plane. Therefore you cannot caputre the
>> muscle's action line if investigation is limited to that plane. This is,
>> effectively, the same thing as saying that for the "TA there are more
>> than one line of action."
>>
>> Thomas M. Greiner, Ph.D.
>> Anatomist and Physical Anthropologist
>> Dept. of Health Professions
>> University of Wisconsin - La Crosse
>> 1725 State Street
>> La Crosse, WI 54601 USA
>>
>> -----Original Message-----
>> From: as572@columbia.edu [mailto:as572@columbia.edu]
>> Sent: Thursday, May 08, 2008 12:16 PM
>> To: BIOMCH-L@NIC.SURFNET.NL
>> Cc: Greiner Thomas
>> Subject: Re: [BIOMCH-L] Locating Tibialis Anterior tendon's action
>> lineusing MRI
>>
>>
>> Dr Greiner,
>>
>> Four thoughts and observations ..
>>
>> 1. The anatomical planes of reference are arbitrary.
>>
>> 2. The line of force or action of any muscle does / do not occur "along
>> an artificial, and arbitrary, geometry" - it occurs where it occurs AND
>> during the range of motion of the involved body segments the position of
>> the line of action of a muscle continuously changes.
>>
>> A long while ago - some anatomists differentiated "Pure" from "Compound"
>> motion.
>> Pure motion was supposed to occur within (parallel to) the three
>> anatomical planes. Compound motion was any movement that
>> simultaneous intersected two or more of the anatomical planes.
>> Fortunately this unwieldy descriptive method is no longer widely used.
>>
>> a. To my knowledge there is no general agreement as to action of the
>> tibialis anterior muscle. In Lanz and Wachsmuth's anatomical atlas, the
>> tendon to the tibialis anterior lies on the axis of inversion and
>> eversion, if that is its true location, i.e. its moment arm relative
>> to this axis is zero. One can therefore conclude that in the
>> anatomical position the TA is neither, and functions as a dorsi-flexor.
>> This conclusion is perhaps most reasonable.
>>
>> I don't recall the reference, but I remember learning that electrical
>> stimulation of the belly of the TA would produce inversion in @50% of
>> cases and in @50% eversion. It may be worth redoing this study.
>>
>> 3b. In the case of the TA it is realistic to consider the reversal of
>> muscle action during the range of motion of the foot at the ankle.
>> This could be associated with the recruitment of muscle force during
>> movement / locomotion.
>>
>> 4. I respectful disagree that the line of action need be in the sagittal
>> plane to obtain meaningful data. It is done mathematically.
>>
>> For Dr. Miller -
>> Most likely, given the width of the tendon and the area of attachment of
>> the TA there are more than one line of action.
>>
>> For Thomas -
>> FYI - I am also an anatomist and physical anthropologist
>>
>> Cheers
>>
>> Dr. Alfonso Solimene
>>
>>
>>
>> Quoting Greiner Thomas :
>>
>>>
>>> I believe the problem you are encountering is due to the fact that
>>> that action of tibialis anterior is oblique to the anatomical
>>> reference planes. You are forcing the measurement of muscle activity
>>> to occur along an artificial, and arbitrary, geometry.. Inasmuch as
>>> tibialis anterior is primarily a foot inverter, I doubt that you would
>>
>>> ever be able to obtain realistic and meaningful measured values if
>>> your perspective is limited to the sagittal plane.
>>>
>>> Thomas M. Greiner, Ph.D.
>>> Anatomist and Physical Anthropologist
>>> Dept. of Health Professions
>>> University of Wisconsin - La Crosse
>>> 1725 State Street
>>> La Crosse, WI 54601 USA
>>>
>>> -----Original Message-----
>>> From: * Biomechanics and Movement Science listserver
>>> [mailto:BIOMCH-L@NIC.SURFNET.NL] On Behalf Of Stuart Miller
>>> Sent: Wednesday, May 07, 2008 9:10 AM
>>> To: BIOMCH-L@NIC.SURFNET.NL
>>> Subject: [BIOMCH-L] Locating Tibialis Anterior tendon's action line
>>> using MRI
>>>
>>> Hello all,
>>>
>>>
>>>
>>> My colleagues and I have recently started to calculate the moment arm
>>> of the tibialis anterior and Achilles tendon. The method we are using
>>> is the Reuleaux graphical analysis. The images of the ankle are
>>> collected using MRI techniques. The images are collected in the
>> sagittal plane.
>>> This technique has been described in Maganaris et al. (1999); Clinical
>>
>>> Biomechanics 14 pp661-666.
>>>
>>>
>>>
>>> The problem we are experiencing is of locating the action line of the
>>> tibialis anterior. The tibialis anterior tendon crosses the sagittal
>>> plane, so only an oval cross-section can be seen. This does not appear
>>
>>> enough to accurately locate the action line of the tendon.
>>>
>>>
>>>
>>> I am wondering if anyone has experienced this problem whilst using
>>> this technique, and if so, can suggest any solutions.
>>>
>>>
>>>
>>> The action line of the Achilles tendon is easy to see as it acts along
>>
>>> the sagittal plane.
>>>
>>>
>>>
>>> I will forward a summary of the responses in a few weeks.
>>>
>>>
>>>
>>> Thank you in advance.
>>>
>>>
>>>
>>>
>>>
>>> Stuart C. Miller BSc. (Hons)
>>>
>>> Centre for Sports Medicine and Human Performance
>>>
>>> Brunel University
>>>
>>> London
>>>
>>> Middlesex
>>>
>>> UB8 3PH
>>>
>>>
>>>
>>>
>>>
>>>
>>> ---------------------------------------------------------------
>>> Information about BIOMCH-L: http://www.Biomch-L.org
>>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>>> ---------------------------------------------------------------
>>>
>>> ---------------------------------------------------------------
>>> Information about BIOMCH-L: http://www.Biomch-L.org
>>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>>> ---------------------------------------------------------------
>>>
>>
>> ---------------------------------------------------------------
>> Information about BIOMCH-L: http://www.Biomch-L.org
>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>> ---------------------------------------------------------------
>>
>> ---------------------------------------------------------------
>> Information about BIOMCH-L: http://www.Biomch-L.org
>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>> ---------------------------------------------------------------
>>
>
> ---------------------------------------------------------------
> Information about BIOMCH-L: http://www.Biomch-L.org
> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
> ---------------------------------------------------------------
>
I think some of the confusion lies in how we define the actions
occurring at synovial joints.
My preference is to specify a joint by locating its axis or axes of
rotation. (The exception is where the axes of rotation are arbitrary
and not anatomically determined , i.e. the gleno-humeral joint - that
is another topic for a later time). Then locate the lines of force /
action of all the muscles working / operating / passing the joint
(more specifically the axis / axes of rotation.
Another of our differences lies in the definition of the movements of
inversion/eversion and supination and pronation.
Simplistically ( or "simple mindedly" - your choice) in- and eversion
occurs about the axes specified by the articular surfaces of the talus
and calcaneous; and supination and pronation occurs about the second
order instantaneous or resulting axis of rotation of the midtarsal,
transverse tarsal or Chopart's joint.
I may be wrong but I think that some investigators "define" these two
terms as occurring about these two joints simulatneously.
I find it difficult understanding why it is necessary to mention that
"... is not pure to the anatomical sagittal plane."
I don't think it is advisable to make any generalization as to the
independance or dependance of two or more joints in a kinematic chain.
I do think it would be useful to consider that any contracting muscle
- concentric, eccentric and isometric, does have an effect on all
joints it works / crosses and not only during concentric contraction.
My two cents for whatever its worth! (Two Cents?)
Cheers
Al
quoting Daniel Cipriani :
> Hello Dr. Solimene,
>
> I do not disagree with your response...I was simply implying that to
> consider the action of the TA, one must consider all the joints it crosses,
> and not simply the ankle joint (dorsiflexion/plantarflexion)...and that if
> one is describing the inversion/eversion action, it is important to identify
> the joint at which this motion occurs. In the earlier discussion, it seemed
> that inversion and dorsiflexion were mentioned without indication of the
> joints involved in these motions (implying only movement at the ankle).
>
> And I agree that the anatomical plane of reference is troubling, given that
> ankle dorsiflexion is not pure to the anatomical sagittal plane.
>
> I also concur that the movement at the ankle joint is not independent of the
> subtalar joint, especially when we are describing a weight bearing action -
> I failed to differentiate between a weight bearing action vs. a non weight
> bearing action of the TA. Thank you for clarifying. Yes, most certainly,
> when a muscle actively shortens, it involves all the axes it crosses.
>
> Daniel
>
>
>
> Daniel Cipriani, PT, PhD
> School of Exercise and Nutritional Sciences
> San Diego State University
> 5500 Campanile Drive
> San Diego CA 92182-7251
> (office) 619.594.1922
> (lab) 619.594.5625
> (fax) 619.594.6553
> http://www-rohan.sdsu.edu/dept/ens/ens_web/faculty/cipriani.htm
>
> -----Original Message-----
> From: as572@columbia.edu [mailto:as572@columbia.edu]
> Sent: Friday, May 09, 2008 9:52 AM
> To: Daniel Cipriani
> Cc: BIOMCH-L@NIC.SURFNET.NL
> Subject: Re: [BIOMCH-L] Locating Tibialis Anterior tendon's actionlineusing
> MRI
>
>
> Dr. Cipriani,
>
> Actually the tendon of the TA crosses several joints on its way its
> distal attachment. I believe it is necessary to define the line of
> action relative to all the joints ( read - axes of rotation) it
> passes. A task I do not believe has been done to this time.
>
> It is questionable if the talo-crural joint and subtalar are truly
> independent. The line of action of a given muscle will "work" all
> the joints it passes.
>
> Firstly, I find it difficult to accept the notion / concept that two
> joints are independent when the movement occurring at these joints
> occurs in different planes.
>
> Secondly, the idea / notion that a description of movement depends
> upon the plane(s) in which that movement takes place is significant
> eludes me.
>
> I believe, from your statement, that our definitions of inversion and
> eversion are different. I don't understand the usage of your term "a
> frontal plane motion" Nor indeed the term "is nearly a sagittal plane
> motion " for the talo crural joint.
>
> My difficulty with the use of anatomical planes to describe motions is
> that it does not take into account for the range of movement and the
> repositioning of the involved joints. It is a static rather than a
> more dynamic and functional approach.
>
> It is my belief that the usage of anatomical planes to describe
> motions and movement unnecessarily complicates descriptions without
> adding any additional useful or functional information. I think it is
> clearer if one depends on body specific references rather than space
> reference terms.
>
> Dr. Alfonso Solimene
>
>
>
> Quoting Daniel Cipriani :
>
>> In response to the discussion on the line of action for the TA, it is
>> important to keep in mind that the TA works across two different joints,
> the
>> ankle joint and the subtalar joint, which are essentially independent.
>>
>> The ankle joint (talocural joint) and the subtalar joint...these two
> joints
>> are independent in that the ankle joint motion is nearly a sagittal plane
>> motion (dorsiflexion/plantarflexion) - keeping in mind that the
> orientation
>> of the axis of motion for the ankle joint is not purely a
> frontal-horizontal
>> orientation. And the subtalar joint motion is mainly of inversion/eversion
>> (a frontal plane motion), and its axis is not purely in the
>> sagittal-horizontal orientation. The line of action of the TA might be
>> described relative to the joint action of interest separately (ankle joint
>> and dorsiflexion/plantarflexion, and the subtalar joint
> inversion/eversion)
>>
>>
>> Daniel Cipriani, PT, PhD
>> School of Exercise and Nutritional Sciences
>> San Diego State University
>> 5500 Campanile Drive
>> San Diego CA 92182-7251
>> (office) 619.594.1922
>> (lab) 619.594.5625
>> (fax) 619.594.6553
>>
>>
>> -----Original Message-----
>> From: * Biomechanics and Movement Science listserver
>> [mailto:BIOMCH-L@NIC.SURFNET.NL] On Behalf Of Greiner Thomas
>> Sent: Thursday, May 08, 2008 10:43 AM
>> To: BIOMCH-L@NIC.SURFNET.NL
>> Subject: Re: [BIOMCH-L] Locating Tibialis Anterior tendon's action
> lineusing
>> MRI
>>
>> A few comments in response to my response on the tibialis anterior. I
>> think we are mostly in agreement, but perhaps talking past each other.
>>
>>
>> "1. The anatomical planes of reference are arbitrary.
>>
>> 2. The line of force or action of any muscle does / do not occur "along
>> an artificial, and arbitrary, geometry" - it occurs where it occurs AND
>> during the range of motion of the involved body segments the position of
>> the line of action of a muscle continuously changes."
>>
>> This was my point exactly, although perhaps you say it better. The
>> anatomical planes are artificial and arbitrary and if you limit your
>> investigation to those planes you should not be surprised that muscle's
>> action line has an oblique orientation.
>>
>> "4. I respectful disagree that the line of action need be in the
>> sagittal plane to obtain meaningful data. It is done mathematically."
>>
>> I agree completely. This is a consequence that a muscle's force of
>> action "occurs where it occurs." That, is another way of saying that you
>> should not expect of find anatomical evidence of a muscular action line
>> if you limit your investigation to a single anatomical plane.
>> Investigations in three dimensions may eventually allow you to resolve
>> an action line to a particular plane, but before you can do that math
>> you need to know what the muscle does when it does something. Inasmuch
>> as Tibialis Anterior is a dorisflexor and an inverter (or perhaps
>> sometimes and everter) the line of action of its insertion tendon will
>> lie oblique to the sagittal plane. Therefore you cannot caputre the
>> muscle's action line if investigation is limited to that plane. This is,
>> effectively, the same thing as saying that for the "TA there are more
>> than one line of action."
>>
>> Thomas M. Greiner, Ph.D.
>> Anatomist and Physical Anthropologist
>> Dept. of Health Professions
>> University of Wisconsin - La Crosse
>> 1725 State Street
>> La Crosse, WI 54601 USA
>>
>> -----Original Message-----
>> From: as572@columbia.edu [mailto:as572@columbia.edu]
>> Sent: Thursday, May 08, 2008 12:16 PM
>> To: BIOMCH-L@NIC.SURFNET.NL
>> Cc: Greiner Thomas
>> Subject: Re: [BIOMCH-L] Locating Tibialis Anterior tendon's action
>> lineusing MRI
>>
>>
>> Dr Greiner,
>>
>> Four thoughts and observations ..
>>
>> 1. The anatomical planes of reference are arbitrary.
>>
>> 2. The line of force or action of any muscle does / do not occur "along
>> an artificial, and arbitrary, geometry" - it occurs where it occurs AND
>> during the range of motion of the involved body segments the position of
>> the line of action of a muscle continuously changes.
>>
>> A long while ago - some anatomists differentiated "Pure" from "Compound"
>> motion.
>> Pure motion was supposed to occur within (parallel to) the three
>> anatomical planes. Compound motion was any movement that
>> simultaneous intersected two or more of the anatomical planes.
>> Fortunately this unwieldy descriptive method is no longer widely used.
>>
>> a. To my knowledge there is no general agreement as to action of the
>> tibialis anterior muscle. In Lanz and Wachsmuth's anatomical atlas, the
>> tendon to the tibialis anterior lies on the axis of inversion and
>> eversion, if that is its true location, i.e. its moment arm relative
>> to this axis is zero. One can therefore conclude that in the
>> anatomical position the TA is neither, and functions as a dorsi-flexor.
>> This conclusion is perhaps most reasonable.
>>
>> I don't recall the reference, but I remember learning that electrical
>> stimulation of the belly of the TA would produce inversion in @50% of
>> cases and in @50% eversion. It may be worth redoing this study.
>>
>> 3b. In the case of the TA it is realistic to consider the reversal of
>> muscle action during the range of motion of the foot at the ankle.
>> This could be associated with the recruitment of muscle force during
>> movement / locomotion.
>>
>> 4. I respectful disagree that the line of action need be in the sagittal
>> plane to obtain meaningful data. It is done mathematically.
>>
>> For Dr. Miller -
>> Most likely, given the width of the tendon and the area of attachment of
>> the TA there are more than one line of action.
>>
>> For Thomas -
>> FYI - I am also an anatomist and physical anthropologist
>>
>> Cheers
>>
>> Dr. Alfonso Solimene
>>
>>
>>
>> Quoting Greiner Thomas :
>>
>>>
>>> I believe the problem you are encountering is due to the fact that
>>> that action of tibialis anterior is oblique to the anatomical
>>> reference planes. You are forcing the measurement of muscle activity
>>> to occur along an artificial, and arbitrary, geometry.. Inasmuch as
>>> tibialis anterior is primarily a foot inverter, I doubt that you would
>>
>>> ever be able to obtain realistic and meaningful measured values if
>>> your perspective is limited to the sagittal plane.
>>>
>>> Thomas M. Greiner, Ph.D.
>>> Anatomist and Physical Anthropologist
>>> Dept. of Health Professions
>>> University of Wisconsin - La Crosse
>>> 1725 State Street
>>> La Crosse, WI 54601 USA
>>>
>>> -----Original Message-----
>>> From: * Biomechanics and Movement Science listserver
>>> [mailto:BIOMCH-L@NIC.SURFNET.NL] On Behalf Of Stuart Miller
>>> Sent: Wednesday, May 07, 2008 9:10 AM
>>> To: BIOMCH-L@NIC.SURFNET.NL
>>> Subject: [BIOMCH-L] Locating Tibialis Anterior tendon's action line
>>> using MRI
>>>
>>> Hello all,
>>>
>>>
>>>
>>> My colleagues and I have recently started to calculate the moment arm
>>> of the tibialis anterior and Achilles tendon. The method we are using
>>> is the Reuleaux graphical analysis. The images of the ankle are
>>> collected using MRI techniques. The images are collected in the
>> sagittal plane.
>>> This technique has been described in Maganaris et al. (1999); Clinical
>>
>>> Biomechanics 14 pp661-666.
>>>
>>>
>>>
>>> The problem we are experiencing is of locating the action line of the
>>> tibialis anterior. The tibialis anterior tendon crosses the sagittal
>>> plane, so only an oval cross-section can be seen. This does not appear
>>
>>> enough to accurately locate the action line of the tendon.
>>>
>>>
>>>
>>> I am wondering if anyone has experienced this problem whilst using
>>> this technique, and if so, can suggest any solutions.
>>>
>>>
>>>
>>> The action line of the Achilles tendon is easy to see as it acts along
>>
>>> the sagittal plane.
>>>
>>>
>>>
>>> I will forward a summary of the responses in a few weeks.
>>>
>>>
>>>
>>> Thank you in advance.
>>>
>>>
>>>
>>>
>>>
>>> Stuart C. Miller BSc. (Hons)
>>>
>>> Centre for Sports Medicine and Human Performance
>>>
>>> Brunel University
>>>
>>> London
>>>
>>> Middlesex
>>>
>>> UB8 3PH
>>>
>>>
>>>
>>>
>>>
>>>
>>> ---------------------------------------------------------------
>>> Information about BIOMCH-L: http://www.Biomch-L.org
>>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>>> ---------------------------------------------------------------
>>>
>>> ---------------------------------------------------------------
>>> Information about BIOMCH-L: http://www.Biomch-L.org
>>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>>> ---------------------------------------------------------------
>>>
>>
>> ---------------------------------------------------------------
>> Information about BIOMCH-L: http://www.Biomch-L.org
>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>> ---------------------------------------------------------------
>>
>> ---------------------------------------------------------------
>> Information about BIOMCH-L: http://www.Biomch-L.org
>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>> ---------------------------------------------------------------
>>
>
> ---------------------------------------------------------------
> Information about BIOMCH-L: http://www.Biomch-L.org
> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
> ---------------------------------------------------------------
>