[BIOMCH-L] Foot Movement

[BIOMCH-L] Foot Movement

Thomas Ferrone

12/23/2003

I have copied a message from biomechanics listserve below for
review. It seems it could be of mutual value.



Subject: [BIOMCH-L] Foot Movement
Survey Results To: <Email Address Redacted>
Dear Friends:
I again thank everyone who has taken the time to respond to my survey on
foot movements. The survey was sent to the Biomechanics, Clinical Anatomy
and Podiatry list servers. I received 50 responses. I will summarize those
responses below. I am now in the process of surveying journal articles and
textbooks for uses and definitions. Eventually, I plan to write this up as a
journal manuscript - any suggestions, especially from editors, about an
appropriate journal would be welcome.
IF YOU HAVE NOT YET RESPONDED TO THE SURVEY you may still do so, but please
send me your response BEFORE reading the rest of this summary. The survey
asked:
Based solely upon your own understanding and experience (ie., without
reference to any written text), please define the following terms. When
possible, please also indicate the specific joint, or joints, where this
movement occurs.
Foot Pronation:
Foot Inversion:
Foot Supination:
Foot Eversion:
If you consider any of these terms to be synonymous, please so indicate.
Your definitions may state that one movement should be considered as a
component of another. Also, please indicate if you never use one, or more,
of these terms to describe foot motions.
Finally, so that I can get a sense of where this diversity is coming from,
please provide the following information about your background:
Highest Degree and Discipline:
Current Specialty:
Are you an active clinician?
Do you consider yourself to be a specialist, or an expert, on the foot?
It would be best if people responded to my personal email
( <Email Address Redacted> ) rather than to the list as a whole. If there is
interest, I will post a summary of my findings to the list.
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Now for the summary:
Undoubtedly some people will quibble over how I combined some definitions
and failed to combine others. Since it was rare that two people would give
me identical definitions, this type of problem is unavoidable. I did not
reject anyone's response unless they told me that they were quoting from a
book or some other authority. I wanted to know how people read and think
about these terms, rather than telling me about some text that may not be
universally consulted. I expect that there were a few instances of
respondents quoting from texts and I failed to recognize the response as a
quotation. All these are methodological problems associated with Internet or
reader response surveys. With these restrictions in place, I consider all
replies as equally valid examples of how knowledgeable and informed people
treat these terms. While the results I report here may not be definitive,
they do give a sense of what's going on.
INVERSION/EVERSION
Definition A: 50% of the respondents agreed that Inversion should be defined
as motion about the long axis of foot so that sole faces medially; and that
Eversion should be defined as motion about the long axis of foot so that the
sole faces laterally.
Definition B: 10% of the respondents came up with a similar definition, but
limited movement to only part of the foot. This definition states that
Inversion is the result of motion about the subtalar joint so that the sole
of the rearfoot faces medially, and that Eversion is motion about the
subtalar joint so that the sole of the rearfoot faces laterally
Definition C: 6% of the respondents also limited their definitions to part
of the foot, but this time it was the forefoot. Inversion was defined as
medial movement of the forefoot in the plane of the sole; and Eversion as
lateral movement of the forefoot in the plane of the sole. Definition C
appears to be the exact opposite of definition B.
Definition D: 4% of the respondents stated that Inversion/Eversion are
inappropriate terms, or lay terms, that should not be used in scientific
discussions of foot movement.
Definition E: 30% of the respondents fall in to this category. Definition E
is not really a single definition, but a conglomeration of the 12 other
definitions that were received. The phrase other probably fits bets for
this group
PRONATION/SUPINATION
Definition 1: 38% of the respondents defined Pronation as motion about the
subtalar joint involving forefoot Eversion, Dorsiflexion and Abduction.
Supination was defined as motion about the subtalar joint involving forefoot
Inversion, Plantarflexion and Adduction. Note that the words Eversion and
Inversion are included in these definitions. Not all of these respondents
agreed on the definition of those terms. So, this definition needs to be
further refined as:
Definition 1A: 22% of respondents used definition A for
eversion/inversion.
Definition 1B: 12% of respondents used definition B for
eversion/inversion
Definition 1D: 4% stated that Eversion/Inversion are
inappropriate terms. This response was particularly interesting since these
terms were used in the definition of pronation/supination!
Definition 1E: 4% used a definition that was included in the
other category. So, for this group Eversion was defined as movement at the
Talocrural Joint in which the sole of the foot is rotated in the coronal
plane to face laterally. A component of Pronation. Inversion was defined as
movement at the Talocrural Joint in which the sole of the foot is rotated in
the coronal plane to face medially. A component of Supination. This
definition of eversion/inversion is essentially the same as Definition A,
except that it specifically states that eversion/inversion are components of
pronation/supination. The main reason I counted this as a separate
definition is because of Definition 2 listed below.
(Yes, I know these numbers don't add up. Some people gave me multiple
definitions.)
Definition 2: 16% of the respondents defined Pronation as motion about long
axis of foot so that the sole faces laterally, and Supination as motion
about long axis of foot so that the sole faces medially. Based upon
Eversion/Inversion Definition A, this response would imply that supination
is a synonym for inversion, and pronation for eversion. However, these
respondents would not agree.
Definition 2B: 4% used definition B for eversion/inversion.
Definition 2C: 4% used definition C for eversion/inversion.
Definition 2E: The remaining 8% were spread out over
definitions in the other category as follows:
2E-a: 4% stated that Eversion is a combination of
Pronation, Abduction and Dorsiflexion, while Inversion is a combination of
Supination, Adduction and Plantarflexion. Notice that this definition claims
that pronation/supination are components of eversion/inversion, which is
contradicted by the next group.
2E-b: 4% stated that eversion/inversion are
movements about the long axis of the foot (similar to definition A), but
that these are not physiological movements and must be viewed as components
of pronation/supination. Effectively respondents that use this definition
are saying that pronation/supination are synonyms with eversion/inversion,
although they don't seem to realize it.
Definition 3: 14% stated that pronation/supination are incorrect or
inappropriate terms for describing motion in the foot.
Definition 4: 32% of respondents fall into the other category, which spans
20 different definitions.
INTERPRETATIONS
I start with what now appears to be the understatement of the century:
Terminology of pedal movements is somewhat confused amongst orthopaedists,
kinesiologists and others. Gray's Anatomy (British) 1989 p. 538
It would seem that while each one of us may have a clear idea of what we
mean by eversion/inversion and pronation/supination we run the risk of
conveying no useful information when we use those terms in communications
with our colleagues. In some cases, we will actually convey information that
is exactly opposite to what we mean.
In response to my first survey summary, some people balked at the high
percentage that appears for Incorrect or Inappropriate term. These people
would often ask - how could someone deny that this movement occurs? I think
that the people that asked this question are missing the point. No one is
denying that any particular movement is occurring, or at least it would be
incorrect to infer that from these survey results. Instead, they are
disputing the proper use of a term to describe that motion. In science there
is the dictum that if it exists, we give it a name. But, it is not logical
to assume that something does not exist just because we have not given it a
name.
I asked respondents to supply some basic information about their academic
background, to see if there is any pattern of definitions that can be
associated with one group more than another. I didn't find one. A few
respondents made me aware of an attempt by the Physical Therapy association
to formalize the use of these terms. I also note that physical therapists,
at least the ones that responded to the survey, are just as variable as the
rest of us in how they use these terms. So much for the efforts of a
professional organization. Still, I do not believe that any one organization
can impose a solution on this problem. Who owns the rights to name
movements? And if one organization claimed that right, what would compel the
rest of us to follow their dictates. For example, the Federative Committee
on Anatomical Terminology has asserted the sole authority in coming up with
the official name for parts of the body - yet how many of us still refer to
the peroneal muscles that were replaced by fibular muscles almost 20
years ago? However, this is not quite the same problem, for even when the
old terms are used we all still understand the meaning.
I noticed that my survey fell short in several areas, and I thereby learned
a few lessons. First, some people wanted to make a distinction between foot
movements and ankle movements. The definitions of pronation/supination and
inversion/eversion may differ depending upon what you are talking about.
While I agree that there can be important differences here, I assumed that
foot was the more generic term that would include the ankle. First
mistake/lesson - do not assume that generic terms are generic for all. Next,
people responded using terms I had never thought about or considered with
regard to foot movement. For example, adduction/abduction were commonly used
terms. To me, these terms do not and cannot apply to the foot/ankle, unless
you are talking about an injury, a pathology or movement of the toes. You
don't need to tell me that most of you would disagree. However, a quick
survey of responses, and the start of my survey of journal articles,
indicates that meanings of adduction/abduction when applied to the foot are
as variable as the meanings of pronation/supination or inversion/eversion.
Also, a number of respondents used the terms varus and valgus to describe
foot/ankle movements. To me, these are terms of morphological condition and
not terms of movement. I found that Biomch-L actually had a heated
discussion on the use of these terms about two years ago - but failed to
resolve the issue. I really should have done some homework first and
included these terms in the survey. Second mistake/lesson - do not assume
that you know all the different terms that researchers use to describe foot
movements. Much of this has rocked my confidence in my ability to describe
movements of the foot/ankle. At this point, I am not entirely sure that
plantarflexion/dorsiflexion mean the same thing to me as they do to everyone
else.
I also note that we, as a community of individuals, are very wedded to our
own set of terms. So much so that we seem to take offense when someone
suggests that our use of these terms is different from the mainstream, or
that our definitions are different from that of our academic group. I noted
this reaction in several private communications, and I also noted it in
myself. I therefore suspect that any solution to this problem is not going
to be simple or quickly adopted. I think a new set of terms, ones that carry
no historic meaning in the context of foot movements, will eventually be the
most useful solution. Until that time, I encourage everyone to define terms
in their communications - no matter how simplistic or textbook those
definitions may seem. And, resist with all your strength the efforts of
reviewers and editors that may try to pressure you into removing those
definitions. I suspect that with your definition in place, many reviewers
will try to convince you that you are using the term incorrectly, when we
all now know that you are merely using it differently.
So, in closing, I give you the sage advise of the philosophers Lennon &
McCartney:
Try to see it my way, only time will tell if I'm right or I am wrong. While
you see it your way, there's a chance that we may fall apart before too
long. We can work it out.
Who would have ever guessed that they were talking about the terms of
foot/ankle movements?
Thomas M. Greiner, Ph.D.
Associate Professor of Anatomy
Department of Basic Sciences
New York Chiropractic College
Seneca Falls, NY 13148-0800 USA