Forriol and Pascual in 1990 (76) proposed the Chippaux Smirak Index (CSI) (Figure 2.5) for assessing the medial longitudinal arch. It defines as ratio of minimum width of the midfoot area (B) to maximum width of the forefoot area (A). Equation of CSI calculated by CSI = B/A. CSI for high arch is 0, normal arch is 0.01 to 0.29, intermediary arch is 0.30 to 0.39, low arch is 0.40 to 0.44, and morphological flat arch is equal or more than 0.45.