目的  基于CT三维重建的载距突，探讨其解剖形态学分型及特征，为螺钉植入治疗跟骨骨折提供解剖学支持。   方法  2019年3月~2020年3月，经纳入标准排除后，最终共收集336例来自西南医科大学附属中医医院的成年人跟骨CT三维重建图像，依据载距突冠状位轴线与跟骨轴线的夹角（β）进行分型，研究参数：β、载距突内侧中点与后距关节面内侧中点的距离（AB），载距突内侧中点与后距关节面外侧中点的距离（AC），载距突内侧中点冠状位轴线与跟骨最外侧交点的距离（AD），载距突内侧中点与跟骨结节内侧突中点的距离（AE），载距突内侧中点与跟骨结节中点的距离（AF），载距突内侧中点与跟骨结节外侧突中点的距离（AG），根据分型和男女、左右分别对测量结果进行统计学分析。   结果  根据 β，我们将载距突分为3型：Ⅰ型（β<70°，68例，20.24%）、Ⅱ型（70°≤β<80°，153例，45.54%）、Ⅲ型（80°≤β<90°，115例，34.23%）。其中Ⅲ型与其他型别在 β、AB、AF上具有差异（P<0.05），Ⅲ型和Ⅰ型在AE上具有差异（P<0.05）。此外，男性和女性的载距突在AB、AC、AD、AE、AF、AG上均具有差异（P<0.05），左右两侧的载距突在 β、AB上具有差异（P<0.05）。   结论  载距突可以分为3型，以Ⅱ型为主，内固定治疗跟骨骨折时，螺钉植入角度可以尽量在70°~ 80°，其解剖形态学分型对螺钉植入有一定的临床指导意义。

Objective  To explore the anatomical morphology and characteristics of the sustentaculum tali based on CT three-dimensional reconstruction, so to provide anatomical support for the treatment of calcaneal fractures with screw implantation.    Methods  From March 2019 to March 2020, a total of 336 adult calcaneal CT three-dimensional reconstruction images from the Affiliated Hospital of Traditional Chinese Medicine of Southwest Medical University were collected after exclusion of inclusion criteria. The CT threedimensional reconstruction of calcaneus was classified according to the β, the prolate axial intersection between sustentaculum tali and calcaneus on the normal posterior. Reference points, β; AB, the distance from the inside of sustentaculum tali to the inside of posterior talar articular surface; AC, the distance from the inside of sustentaculum tali to the outside of posterior talar articular surface; AD, the distance from the inside of sustentaculum tali to lateral of calcaneal; AE, the distance from the inside of sustentaculum tali to medial process of calcaneal tuberosity; AF, the distance from the inside of sustentaculum tali to calcaneal tuberosity; AG, the distance from the inside of sustentaculum tali to lateral process of calconeal tuberosity. The results were statistically analyzed according to type, sex and body side.    Results  Under the β, the sustentaculum tali was classified into three types: typeⅠ(β<70°, 68 cases, 20.24%), type Ⅱ(70°≤β<80°, 153 cases, 45.54%), type Ⅲ(80°≤β<90°, 115 cases, 34.23%). For the distance of β, AB, AF, there were statistical differences between type Ⅲ and other types (P<0.05). For the distance of AE, there were statistical differences between type Ⅲ and typeⅠ(P<0.05). Meanwhile, for the distance of AB, AC, AD, AE, AF, AG, there were statistical differences between male and female (P<0.05). For the distance of  β, AB, there were statistical differences between right and left (P<0.05).    Conclusion  Under the β, the sustentaculum tali is classified into three types, with the typeⅡas the main type. When treating calcaneal fractures with internal fixation, direction of screw implant can choose between 70° to 80° as soon as possible. The morphology and classification of sustentaculum tali are of certain clinical implication to treat calcaneal fractures.