Department of Paramedical Science, SCPM College of Nursing & Paramedical Sciences, Gonda, India
Background: In forensic anthropology, age and sex estimation are crucial for identifying unknown human remains. The sternum, due to its predictable ossification and protected anatomical location, offers valuable markers for such evaluations, especially in adult individuals. Advancements in computed tomography (CT) imaging now allow for accurate, non-invasive assessment of sternal fusion and morphometry. Objective: This study aimed to evaluate the fusion status of the manubriosternal and xiphisternal joints and assess sternal morphometric parameters using CT imaging for forensic age and sex estimation in an Indian population. Methods: A cross-sectional study was conducted on 100 adult chest CT scans (50 males, 50 females). Measurements included total sternal length, manubrium and body lengths, and the fusion status of sternal joints. Statistical analysis involved chi-square tests, t-tests, and Pearson’s correlation. Results: A significant correlation was observed between xiphisternal joint fusion and age (p = 0.003), supporting its role as a reliable age marker. Males had significantly longer sterna than females (p < 0.001), indicating sexual dimorphism. However, fusion patterns alone were not significantly different between sexes (p = 0.249). Conclusion: CT-based sternal assessment is a reliable and non-invasive method for age and sex estimation in forensic practice. The results highlight the need for population-specific reference standards, particularly in the Indian context.
Accurate estimation of age and sex from human skeletal remains is a cornerstone of forensic anthropology and medicolegal investigations. Traditionally, the pelvis, skull, and long bones have been primary skeletal markers due to their pronounced sexual dimorphism and known developmental timelines. However, in cases involving fragmentation, decomposition, or thermal damage—such as mass disasters or criminal cases—these bones may not be preserved. In such contexts, the sternum emerges as a valuable alternative for forensic identification due to its central location, predictable fusion patterns, and protection within the rib cage structure [1,2]. The sternum, or breastbone, is a flat bone situated in the midline of the anterior thoracic wall. It comprises three distinct components—the manubrium, body (gladiolus), and xiphoid process—that develop from separate ossification centers and gradually fuse over the human lifespan [3]. This biological characteristic allows radiologists and forensic anthropologists to correlate the fusion status of the manubriosternal and xiphisternal joints with chronological age, particularly in adult populations where other skeletal indicators are less informative [4,5]. Recent advancements in multidetector computed tomography (MDCT) and 3D imaging techniques have enabled high-resolution visualization of sternal morphology and ossification patterns. CT-based analysis offers numerous advantages over traditional radiography, including higher precision, reduced inter-observer variability, and the ability to reconstruct detailed anatomical models without invasive procedures [6,7]. The ability to perform non-invasive, reproducible morphometric measurements has made CT imaging a preferred method for forensic evaluations of the sternum. Moreover, the sternum exhibits measurable sexual dimorphism. Males typically have longer and wider sterna, whereas females present shorter and narrower configurations [8]. Morphometric parameters such as total sternal length, manubrium width, and the sternal index have been shown to achieve high accuracy (up to 90%) in sex estimation when applied through discriminant function analysis [9]. However, these measurements often vary significantly across different ethnicities, necessitating the development of population-specific reference data for forensic application [10]. In the Indian context, few studies have explored the radiological assessment of sternal features for forensic purposes. Given the genetic, environmental, and lifestyle diversity in the Indian population, establishing localized CT-based standards is essential to improve the accuracy of forensic identification. This study aims to evaluate the sternal fusion patterns and morphometric differences using CT imaging and assess their forensic applicability in age and sex estimation among adults in a North Indian population.
METHODOLOGY
2.1 Study Design
This research was conducted using a descriptive cross-sectional design, analyzing retrospective CT scan data to evaluate the fusion status and morphometric parameters of the sternum. The study employed a quantitative observational approach, enabling objective measurement and statistical correlation of anatomical features with demographic variables.
2.2 Study Setting
The study was carried out in the Radiology Department of SCPM Hospital and Medical College, Gonda, Uttar Pradesh, India. CT images were retrieved from the hospital’s Picture Archiving and Communication System (PACS), which stores digital radiological data, including chest CT scans from patients across various age groups.
2.3 Sample Selection
2.3.1 Target Population
Adult individuals aged between 18 and 70 years who underwent thoracic CT imaging for diagnostic purposes unrelated to trauma or musculoskeletal disorders.
2.3.2 Sampling Technique
A purposive sampling method was used to select CT scans based on inclusion and exclusion criteria.
2.3.3 Sample Size
The final sample included 100 individuals, comprising:
The sample size was determined based on feasibility, availability of suitable imaging records, and time constraints.
2.4 Inclusion and Exclusion Criteria
Inclusion Criteria
Exclusion Criteria
2.5 Imaging Modality and Tools
2.6 Measurement Parameters
The following morphometric and fusion parameters of the sternum were recorded:
Fusion status was graded as:
2.7 Reliability and Validity
2.8 Data Collection Procedure
2.9 Statistical Analysis
A p-value < 0.05 was considered statistically significant.
RESULTS
A total of 100 CT scans (50 males and 50 females) were analyzed to evaluate sternal fusion patterns and morphometric differences for the purposes of forensic age and sex estimation.
3.1 Demographic Distribution
The majority of participants (33%) were in the 31–45-year age group. The 46–60 group followed closely at 30%. This distribution supports the evaluation of age-related fusion patterns across early, middle, and late adulthood. Slight over-representation of females in the youngest group may influence early fusion trends.
3.2 Fusion Status of Manubriosternal and Xiphisternal Joints
The xiphisternal joint shows a higher rate of complete fusion (46%) compared to the manubriosternal joint (32%).
3.3 Morphometric Comparison Between Males and Females
|
Sternal Parameter |
Male (Mean ± SD) |
Female (Mean ± SD) |
p-value |
|
Total Sternal Length (mm) |
168.2 ± 12.1 |
153.7 ± 11.4 |
< 0.001 |
|
Manubrium Length (mm) |
51.5 ± 4.6 |
47.3 ± 4.1 |
< 0.01 |
|
Sternal Body Length (mm) |
116.7 ± 10.3 |
106.4 ± 9.5 |
< 0.01 |
|
Sternal Index (%) |
44.1 ± 3.5 |
44.5 ± 3.2 |
0.65 |
3.4 Fusion Status of Xiphisternal Joint vs. Age Group
|
Age Group (Years) |
Unfused |
Partially Fused |
Fully Fused |
|
18–30 |
10 |
8 |
4 |
|
31–45 |
6 |
12 |
15 |
|
46–60 |
2 |
10 |
18 |
|
61–70 |
0 |
6 |
9 |
Statistical Test: Chi-square (χ² = 19.80, df = 5, p = 0.003)
There is a statistically significant association between xiphisternal fusion and age group (p = 0.003). Fusion tends to increase progressively with age, with fully fused joints peaking in the 46–70 age group. This confirms the xiphisternal joint as a reliable marker for age estimation, particularly in older adults.
3.5 Total Sternal Length Between Males and Females (Independent t-test)
|
Sex |
Mean Length (mm) |
SD |
t |
df |
p-value |
|
Male |
168.2 |
12.1 |
|||
|
Female |
153.7 |
11.4 |
6.17 |
98 |
< 0.001 |
A statistically significant difference in total sternal length exists between males and females (p < 0.001). The result confirms sexual dimorphism and supports the use of sternal length as a discriminant parameter for sex estimation in forensic analysis.
3.6 Xiphisternal Fusion by Sex
|
Fusion Grade |
Male (n=50) |
Female (n=50) |
|
Grade 1 (Unfused) |
6 |
12 |
|
Grade 2 (Partially Fused) |
18 |
18 |
|
Grade 3 (Fully Fused) |
26 |
20 |
Statistical Test: Chi-square (χ² = 2.78, df = 2, p = 0.249)
While males showed a higher rate of complete fusion, the difference between sexes in xiphisternal fusion was not statistically significant (p = 0.249). Thus, fusion status alone is not a reliable indicator of sex and should be used in conjunction with morphometric measurements.
DISCUSSION
The current study aimed to evaluate the forensic utility of sternal fusion patterns and morphometric characteristics using computed tomography (CT) imaging for age and sex estimation in an Indian adult population. The findings strongly support the use of xiphisternal joint fusion as a reliable indicator of chronological age, while sternal morphometry, particularly total sternal length, emerged as a statistically significant parameter for sex determination. A significant proportion of participants exhibited complete fusion of the xiphisternal joint (46%), with a clear upward trend correlating with increasing age (p = 0.003). This observation aligns with prior studies by Chiba et al. (2018) and Tellioglu et al. (2021), both of whom demonstrated that the xiphisternal joint typically begins to ossify after the age of 40 and is commonly fused by 60 years of age [2,4]. This gradual and consistent pattern of fusion makes the xiphisternal joint a dependable marker in forensic age estimation, especially in adult and elderly individuals where other skeletal markers are often less reliable. In contrast, the manubriosternal joint showed more variability in fusion, with only 32% completely fused and 28% remaining unfused. This variability may be attributed to genetic and environmental factors influencing ossification rates, as previously suggested by Ekizoglu et al. (2014), who emphasized that fusion at this joint can be incomplete even in older adults [6]. Therefore, while the manubriosternal joint provides supplementary information, it should not be used as a sole indicator for age determination. Regarding sex estimation, our analysis revealed statistically significant differences between males and females in key morphometric parameters, particularly total sternal length (p < 0.001) and manubrium/body length. These results are consistent with the findings of Garvin and Ruff (2010), who reported pronounced sexual dimorphism in sternal dimensions, with males exhibiting longer and broader sterna than females across African-American and European-American samples [1]. Similarly, Kim and Lee (2019) reported comparable results in a Korean population, where discriminant function analysis using CT-measured sternal dimensions achieved over 80% classification accuracy [8]. However, the sternal index—a ratio comparing manubrium to body length—did not show significant variation between sexes (p = 0.65). This suggests that while the absolute dimensions differ, the relative proportions between sternal components are relatively consistent across sexes. This result is echoed in studies by Mahakkanukrauh et al. (2015) and Silva et al. (2020), both of which acknowledged the limited reliability of the sternal index as a standalone sex determinant [7,9]. Interestingly, the fusion status of the xiphisternal joint did not significantly differ between males and females (p = 0.249), although males showed a slightly higher proportion of complete fusion. This reinforces the notion that while morphometry is strongly sexually dimorphic, fusion patterns are more age-dependent and less influenced by sex, a conclusion also drawn by Obertová et al. (2017) in their large-scale European CT-based study [5]. One of the major strengths of this study lies in its use of high-resolution MDCT imaging, which allows for precise and non-invasive evaluation of sternal morphology and ossification. CT-based studies have consistently outperformed traditional radiographs in both resolution and reproducibility, as emphasized by Badole et al. (2022) in their Indian forensic radiology review [10]. Furthermore, the ability to perform measurements digitally reduces observer bias and enhances the statistical reliability of forensic assessments. Nonetheless, this study is not without limitations. The sample size (n=100), while adequate for preliminary statistical analysis, limits generalizability across broader regional or ethnic variations within India. Additionally, the retrospective nature of data collection and the lack of longitudinal follow-up restrict causal interpretation. Future multicentric studies with larger, stratified samples are recommended to develop population-specific standards and improve accuracy in forensic identification.
CONCLUSION
This study confirms that CT-based evaluation of sternal fusion patterns, particularly at the xiphisternal joint, is a reliable method for age estimation, while sternal morphometric measurements such as total sternal length significantly aid in sex determination. The findings reinforce the value of using computed tomography in forensic identification, especially in situations where conventional skeletal remains are unavailable or damaged. Establishing population-specific reference data is essential to improving accuracy and reliability in the Indian forensic context. Overall, the sternum—when assessed radiologically—serves as a practical, non-invasive tool in forensic science.
REFERENCE
Vivek Kumar Yadav*, Shivam Kumar, Radiological Evaluation of Sternal Fusion Pattern Including Manubriosternal and Xiphisternal Joints for Age and Sex Determination Using Computed Tomography of the Chest, Int. J. Sci. R. Tech., 2025, 2 (11), 189-194. https://doi.org/10.5281/zenodo.17557714
10.5281/zenodo.17557714
