Areal measurements of subtalar articular facets for example. (A) After the segmentation, the SSD reconstruction image of the 3D calcaneus presented the anterior (blue arrow), middle (yellow arrow) and posterior (red arrow) facets clearly. (B) The operator marked the border of the articular facet. The border (red curve) was actually unbroken, though part of the red curve seemed not visualized. (C) With the help of the perspective mode of SSD reconstruction, the defined boundary of the surface could be observed. (D) On the anterolateral view, the boundary of each articular facet was clear. Each area was calculated by the software (yellow arrow).