Role of passive structures in the mobility and stability of the human subtalar joint: a literature review.

The subtalar joint plays a fundamental role in the transmission of loads between the leg and the foot. Although anatomical structures of this joint have been described extensively, much ambiguity about their location, shape, and function still persists. There is also disagreement regarding mobility, for example, whether the joint can be considered a hinge, screw-like, or a multiaxial joint. The most relevant studies from the literature are reported and the main experimental observations discussed. Recent studies have described the subtalar joint as a structure with no degrees of unresisted freedom, i.e., motion from the single neutral position is attained only by deformation of the ligaments and of the articular surfaces.