[The importance of the long tensile system of the sole of the foot for the action of the metatarsus (optical potential study of a model)].

The importance of the plantar tensile systems of the foot are studied by the means of photoelasticity. In a plastic (VP 1527) model of the sagittal section of a foot skeleton the distribution of stressing under load has been visualized in photographs of the isochromes as seen in the polarized light. This examination has been carried out with and without tension in the long plantar tensile systems of the model. It has clearly been shown that by the influence of the tensile systems the resultant force for the forefoot runs approximately in the axis of the bony elements of the metatarsus. In absence of these plantar tensions on the contrary the metatarsal elements undergo considerable bending stresses.