At 11:22 AM 12/15/01 -0500, you wrote:
>Recently, this comment was made on one of this or another similar list:
>
><Pronation is not a single plane movement, it is triplanar.  "It combines
>components of eversion, abduction and dorsiflexion of the lower segment of
>the foot in open chain.  In closed chain, the calcaneus everts under the
>talus and the talus plantarflexes, adducts and glides foward on the
>calcaneus.  The floor abducts and dorsiflexes
>the forefoot around the mid-talar joint (MTJ) oblique axis, and inverts the
>forefoot around the MTJ longitudinal axis." (Cusick, 1995) >

Hi Dr. Mel -

Cusick here...  And for 30 years I've wrestled with the "considerable
difference of opinion regarding the disposition of the foot during various
activities." As an instructor, I have found that by observing the movements
of the various foot joints as they occur in each of the three cardinal
planes, I can grant clarity to the relevance of axial inclination, to the
variances that are seen in the same deviations into pronation and
supination as evidence of planar dominance, and to deriving a plan for
restoring a more ideal alignment while molding a cast for an orthosis, a
splint, or a series of casts.

I did not define pronation and supination as entire lower limb actions
because I was discussing them at the foot - not the forearm - at the time.
And their influences on leg, knee, and hip motions are worth noting in a
discussion of the closed chain,  but not in the definition.

As Christmas is looming and my daughter is 4, I'm not prepared to launch a
dissertation on this topic at the moment, but I do urge any who are
interested in this issue to go to my website, where I've posted a lengthy
discussion of the nomenclature
and an offer to participate in the honing of it into a meaningful body of
terms. www.gaitways.com .

So Happy Holidays!!  I'll be back on the case in a week or so!

Regards -

Beverly Cusick, PT, MS



>*** This comment is very important to note, because there is often
>considerable difference of opinion regarding the disposition of the foot
>during various activities.  Many authors refer quite casually to foot
>problems being caused by excessive pronation or supination of the foot, but
>others point out that these terms are inaccurate and should be replaced by
>eversion and inversion, respectively.
>
>That physio comment above, while correct in stressing the triplanar aspects
>of "pronation", at the very least should rather have stated that "what is
>commonly referred to as pronation of the foot involves triplanar actions of
>the entire lower extremity."
>
>According to the basic definitions, pronation takes place about a single axis
>(along the length of the foot or hand) and simply means the turning over of
>the surface of the hands or feet so that their surfaces face partially or
>fully downwards, while supination refers to the turning over of those
>surfaces to face upwards. In other words, pronation and supination are
>defined as uniplanar actions.
>
>On the other hand, eversion, ostensibly simply meaning a "turning outwards"
>and "inversion", ostensibly meaning a "turning inwards", are terms that have
>never been defined as uniplanar actions along a single given axis, since they
>involve action of all joints of the lower extremities in several planes.
>Eversion certainly does not refer to rotation about the axis of the leg or
>the arm, since that action  is known as internal or external rotation, nor
>does it refer to inward or outward displacement to or away from the midline
>of the body, since those actions are adduction or abduction.  Finally,
>eversion and inversion do not refer to rotation of the foot about a specific
>axis of the ankle, since those actions are known as plantarflexion or
>dorsiflexion.
>
>In other words, inversion and eversion have never been defined to be any form
>of uniplanar action, so it would be interesting to know where the notion
>arose that regards these actions as being some special fundamental joint
>action.  This view suggests that eversion and inversion, like flexion,
>internal rotation and abduction, are fundamental actions about a given joint
>that involve no actions about any other axes, but they are not, as the above
>process of "reductio ad absurdum" has shown.
>
>Eversion is a complex action involving pronation, lateral rotation, valgus
>("knee knocking"), dorsiflexion and adduction of the various joints of the
>lower extremity in open chain situations, whereas inversion involves the
>inverse of all of those actions.  Presumably one could also refer to
>eversion, inversion, pronation and supination of the upper extremities if one
>were standing or walking on the hands, as is the case in gymnastics and
>circus acts.
>
>Thus, if one attributes knee injuries to excessive pronation, this may be
>profoundly misleading, since what one believes to be simple pronation
>invariably involves differing degrees of angular displacement of all joints
>of the lower extremity.  For example, one may pronate with the knees pointing
>directly forwards, outwards or even  inwards with significant valgus (noting
>that 'pure' pronation of the sole of the foot is not possible with the knees
>fully extended); the consequences for the knees will be very different.
>Incidentally, the last mentioned situation represents potentially the most
>harmful posture for activities such as running and squatting.
>
>Dr Mel C Siff
>Denver, USA
>http://groups.yahoo.com/group/Supertraining/