Anomalous calcaneus secundarius: Anatomical and clinical considerations

Objective: Calcaneus secundarius (CS) is an accessory bone of the anterior calcaneal facet. The main aim of the present study was to look for the presence of CS in the osteological repository. Design: An osteological study on the calcaneus. Materials and Methods: Three hundred calcaneus (irrespective of side) were collected from the bone repository in Forensic Osteology Research Centre, Chiang Mai University, Thailand. The calcaneus was studied for the presence of CS. Appropriate measurements were taken. Results: Out of 300 bone specimens of calcaneus, only 2 specimens (0.66%) exhibited anomalous CS (one left and one right calcaneus). On the left calcaneus, the maximum vertical lengths of anterior facet and posterior facets were 7.71 mm and 17 mm, respectively and the maximum vertical distance from the anterior till the posterior facet was 26.97 mm. On the right calcaneus, the maximum vertical lengths of anterior facet and posterior facets were 4.13 mm and 16.97 mm, respectively and the maximum vertical distance from the anterior facet till the posterior facet was 25.49 mm. No other associated anomalies were observed. Conclusion: Presence of abnormal CS may be important for distinguishing it from any fractures. Presence of CS may also cause unnecessary pain in any individual.