Tibialis posterior: a review of anatomy and biomechanics in relation to support of the medial longitudinal arch.

The medial longitudinal arch is unique among homo sapiens. This specialization of the human foot is believed to be necessary to the habitual bipedal gait pattern. Mechanical integrity of the arch depends on static and dynamic anatomic factors. The posterior tibial tendon in particular is situated to provide dynamic support along the plantar aspect of the foot and arch. Evaluation of the phasic activity of the posterior tibial muscle appears to confirm this premise. Furthermore, changes in the longitudinal arch that occur when the posterior tibialis is deficient lend further evidence that it is important in maintenance of the normal arch.