(Revision of a Post on the SOT Forum, January 13, 2006 #2149)
Reversing poor posture (postural distortions) in children over the age of 8-9 requires a multi-disciplinary approach even when the postural problem is initiated by abnormal foot motion. In order to understand the inherent limitations of treating the foot only (e.g., the PMS imbalance), a brief discussion of the pathodynamics engaging the feet, cervical spine, cranium and teeth are presented below. In an ascending pattern, these changes predominantly occur sequentially, from bottom to top.
In the Ascending Foot - Cranial Model suggested by Rothbart, The Primus Metatarsus Supinatus imbalance drives the innominates anteriorly (externally), which, in turn can drive the temporal bones into an anterior (internal) rotation, the more pronated foot being ipsilateral to the more anteriorly (internally) rotated temporal bone (Rothbart BA 2007. JAPMA, in press).
Anterior (internal) rotation of the temporal bones can force the sphenoid bone into an extended and side bent position. This can unbalance the maxilla resulting in a (1) loss of facial vertical dimension (see Photos), and (2) narrowing of the Curve of Spee (dental arch), which can crowd the teeth and, if severe enough, 'block out' the emergence of the primary cuspids (See Figure 1, left). These occlusal changes are secondary to the unleveling of the cranial bones. That is, the cranial imbalances are in place before the primary teeth erupt. Succinctly, the bite, in large measure, is determined by the pre-existing cranial imbalance(s).
Cervical imbalances (displacement of the atlas on the axis) may result from maxilla cants. This occurs because the maxilla's axis of rotation lies between C1 and C2. Cervical imbalances can drive the sacrum into nutation (descending disruption) while reinforcing the cranial imbalance. If treatment is only directed towards stabilizing the primary foot imbalance (e.g., Primus Metatarsus Supinatus), the secondary cervical imbalance can maintain the (1) head forward position, and (2) sacral nutation (anteriorly displacement).
Occlusions should not be corrected until the head is positioned over the spine and the cranial and/or cervical imbalances are stabilized.



