Dear Kevin and All,

"Lateral Foot Imbalance" has been around for a long time, perhaps before the
50's when "lateral forefoot imbalance"( viz. due to forefoot valgus, 1st ray
plantarflexion, lateral column planus,  short or hypermobile fourth-fifth
segments, etc. ) were measured by L. Schreiber and H. Weinerman of N.Y. with
their "supronimerter" device( see JAPA of the 50's ).

To these earlier lateral forefoot deficiencies, we would currently cite
certain lateral midfoot entities of metatarsus adductus, forefoot adductus,
calcaneocuboid instability, peroneus longus, brevis, and possibly tertius
dysfunction( PLD, PBD, PTD ).

Posterior lateral deficiencies may also involve the lateral peroneal muscles
plus the calcaneal tuber deformities which invite posterolateral sprains,
turning tendency, etc.
(i.e. calcaneal tuber varus, adductus, and more commonly, tuber adductovarus
).

One point, however, is that with a lateral foot supinating tendency, it is
the medial supinating muscles, as indicated by Hicks, which tend to preserve
the equilibrium by shifting the foot and ankle lateralward in an effort to
neuralize an existing or impending body imbalance.  D. J. Morton, Vierodt,
and the brothers Ducroquet compare the maintenance of unipodal equilibrium to
an act of juggling the body-limb column on the talus
and calcaneus, centering at the subtalar joint.  Kevin, you and I might
disagree as to the
actual mechanism and source of subtalar balancing, but I hope we may agree
that a Rotational Equilibrium in the frontal plane develops at the subtalar
joint and that, without
such a balancing mechanism, medial/lateral body equilibrium would be
jeopardized.

>From your posted remarks, I gather you believe that the lateral peroneal
muscles preserve the supinating tendency in a normal foot.  It can be
observed, however, that when the normal foot is supinated or supinating in
stance, the peroneal muscles are quiescent while the medial supinator
muscles( such as the tibialis anterior and posterior ) are most active.  This
is why, in my earlier postings on the lateral ankle sprain , I tried to
propose that the typical lateral ankle sprain was an active supinator
miscalculation event relating to the terrain expectation .  I think I lost
that argument and will probably repeat the loss here.

Cordially,

Alan


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%