Calcaneal Articular Talar Facets, Stieda’s Process, and Calcaneus Secundarius: Variations Found in Thai Population

Objective: The calcaneus and talus have been studied in anatomy and pathology, but research is limited compared to its forensic use. This study examines the prevalence of three types of variants (calcaneal talar facet types, Stieda’s process, and calcaneus secundarius) to find correlations with sex and siding of the calcaneus and talus in a Thai population. Materials and Methods: A total of 250 specimens from the bone collection of Siriraj Anatomical and Anthropological Bone Research Centre (Si-AABRC), Thailand, were used. The calcaneus was classified into three types based on its articular talar facets, and the talus was categorized based on the presence of Stieda’s process and four types of posterolateral tubercles. Presence of a calcaneus secundarius was checked for a crescent-shaped notch and an accessory ossicle. Results: Pattern I, the most common facet type, accounted for 60.23% of calcanei, with a 45.2% average of “full-shaped” facets. Pattern III was the least common, averaging 4.4%. The flat posterior processes of the talus were the most frequent trait (41.4%), while the hook type was the least common (2.4%). Calcaneus secundarius (CS) and Stieda’s process (SP) were the rarest traits. Conclusion: The aforementioned calcaneal and talar traits can aid in investigating sides, as left or right, but not as a specific sex characteristic. The calcaneus secundarius has no correlation to either sex or siding due to limited samples. The outcomes of prevalence align with prior studies.