How Sub-Talar Joint Affects Flat Feet
- Flat Feet
- Sub-talar Joint
- subtalar joint is oriented oblique to the axis of ankle joint motion (between 20° and 57°);
- talar head is supported by the anterior process of the calcaneus;
- w/ foot eversion, the calcaneus no longer supports the head of the talus, which deviates medially and plantarward, dropping into
the medial aspect of the foot which causes the arch to become less pronounced;
- w/ flat feet, axis of sub talar joint is more horizontal which allows more inversion and eversion (and less internal and external rotation);
- w/ flat feet, the longitudinal axis is moved more medially (than the normal 23 deg deg) which has the effect of allowing more dorsiflexion
and plantar flexion;
- this is in contrast to cavus feet in which the axis is decreased which decreases the amount of dorsiflexion and plantarflexion);
- as a result in the change in the sub-talar axis, there is greater relative inversion-eversion and dorsiflexion and plantarflexion (i.e. there is a
greater supinatory and pronatory effect upon the foot)
Biomechanics and Orthotics of the Foot in Athletes.
Original Text by Clifford R. Wheeless, III, MD.
Last updated by Data Trace Staff on Thursday, April 12, 2012 12:43 pm