Tibial rotation.

The rotation of the tibia and subtalar motion are being taken into account in some of the newer techniques for leg bracing. It is the purpose of this paper to investigate the precise relationship between these two movements. The rotation of the tibia in a horizontal plane, occurring during stance, is rotation about a simple vertical axis to a limited degree only. The major range of tibial rotation is contributed by the subtalar joint which has a compound axis so directed as to produce tibial rotation as a primary movement. It has been customary to view subtalar motion from the aspect of the various planes in which the foot moves during inversion-eversion, i .e ., the frontal, sagittal, and horizontal planes . This, however, is essentially a non-functional concept . When the foot is on the ground, it would be more pertinent to be concerned with what happens to the segment proximal to the subtalar joint—the tibia. During the stance phase, tibial rotation becomes dependent on the motion of the joints between the tibia and the floor . These are primarily: 1. The subtalar (peritalar) joint 2. The ankle joint 3. The mid-tarsal joint The following describes a method for simulating the rotation of the tibia as it occurs in relation to these three joints.