Age Estimation Based on CT Chest Analysis of Ossification of the Xiphisternal Joint in a Living Population Aged 35-50 in a Tertiary Setup

Introduction Age estimation has been an area of special interest in the medicolegal context because of its necessity in various criminal and civil cases like assaults, murders, rapes, inheritance, insurance claims, etc. While legal documents are useful in daily activities that require age identity, they cannot be relied on for criminal and civil proceedings because of being falsifiable and inaccessible to some people. Scientific methods of age determination like physical, dental, and radiological examinations are used for reliable age estimation due to their universal and non-falsifiable nature. The skeletal examination is of great importance here because the human skeleton provides many sites for age estimation in different age groups. The xiphisternal joint between the xiphoid process and the body of the sternum provides one such opportunity in participants of 35-50 years of age. The ossification in this joint proceeds gradually in approximately the third to fifth decade of life; this natural variation in the morphology of the joint can be leveraged for age estimation. Previous studies showed that the mean age of fusion varied with the ethnicity of individuals and environmental factors. Thus, it is critical to have statistical information for the concerned population to avoid errors. Also, the relation of gender with the mean age of complete fusion remained ambiguous with the previous studies. The xiphisternal joint can be studied by radiological techniques like computed tomography (CT) and plain radiographs. Radiological methods have the benefit that they can be used on both living and dead participants and are non-invasive. The present study aims at gathering data relevant for use in India (Maharashtra) and to find out the reference age group in which there is complete ossification of the xiphisternal joint in males and females. Methods and materials This was a cross-sectional observational study in a tertiary care setup over a period of one year. High-resolution computed tomography (HRCT) was used for assessing joint fusion due to its high spatial resolution. The participants were included in the study if they were referred for HRCT chest by a physician for some pathology, did not have any trauma or lesion of the sternum and consented to the use of their information for the purpose of this study. Results The study included a total of 384 participants, out of whom 195 (50.8%) were males and 189 (49.2%) were females. The mean age of participants was 42.87 years. The mean age of complete xiphisternal joint fusion was observed to be 46.31 years (95% CI: 45.61 to 47.00) in males and 45.57 years (95% CI: 44.73 to 46.42) in females. Similarly, the mean age of participants with an unfused xiphisternal joint was observed to be 38.42 years (95% CI: 37.47 to 39.39) in males and 37.85 years (95% CI: 37.14 to 38.57) in females. There was no statistically significant difference in the age above which males and females show complete ossification of the xiphisternal joint. Conclusion The xiphisternal joint fusion can be used to determine the chronological age of an individual. It can be estimated as lesser than or equal to 45 years if the xiphisternal joint is unossified and greater than or equal to 37 years if the joint is ossified, with a 95% level of confidence.