Abstract
Recently, the number of foot joint syndromes by an acquired transformation increases. Because loading condition and the structure of foot joint greatly influence them, the clarification of the mechanical property of foot joint is important. Especially, a flatfoot has a lot of patients as an acquired case. In this research, the bone in the arch of a normal foot and a flat foot was reproduced by three -dimensional model, the stress distribution was analyzed by the photoelastic investigation, and it made comparative study of them. The experiment analysis result showed the following things. It is calcaneus that change was looked at by especially stress distribution, and the stress value became high in the flat state outside in the normal condition at inside sidewall. If this will be in a flat state, it will be considered to be because for calcaneus to rotate inside.
