Department of Paramedical Science, SCPM College of Nursing & Paramedical Sciences Lucknow Road, Haripur, Gonda, U.P. - 271003
Background: The frontal sinus, an anatomically variable structure within the human skull, serves multiple physiological roles and holds significant forensic and diagnostic value. Due to its uniqueness and postmortem durability, frontal sinus morphology has emerged as a reliable tool in human identification. Objective: This study aimed to evaluate the size, shape, symmetry, and anatomical variations of the frontal sinus using digital radiographs in individuals from Western Uttar Pradesh, India. It also sought to explore differences based on sex and investigate associations with nasal septal deviation. Methods: A cross-sectional observational study was conducted on 200 digital occipitofrontal (Caldwell view) skull radiographs. Measurements of frontal sinus height, width, symmetry, shape, and septal deviation were recorded. Statistical analyses included descriptive statistics, t-tests, and chi-square tests, with a significance level set at p < 0.05. Results: Asymmetrical frontal sinuses were present in 72.5% of participants, while symmetrical sinuses were observed in 27.5%. Mild septal deviation was the most common (48%), and triangular sinus shape was most frequently noted (38.5%). Males had larger sinus dimensions than females, though differences were not statistically significant. No significant association was found between septal deviation and sinus symmetry (p = 0.849). Frontal sinus agenesis was observed in 4.5% of individuals. Conclusion: The findings affirm the high individual variability of frontal sinus morphology and its potential utility in forensic identification. The study supports the use of digital radiography as an effective and affordable method for anatomical assessment, especially in resource-limited settings. Establishing regional morphometric databases enhances both forensic and clinical applications.
The frontal sinuses are a pair of air-filled cavities located in the frontal bone of the human skull, positioned just above the eyes and behind the eyebrows. As part of the paranasal sinus system, they play essential physiological and clinical roles, including reducing cranial weight, warming and humidifying inspired air, and contributing to vocal resonance [1]. Each individual's frontal sinus exhibits a unique morphological pattern—comparable to fingerprints—making it a valuable biometric marker in forensic identification [2]. Morphologically, the frontal sinuses vary widely in shape, size, and symmetry among individuals. This variation is influenced by factors such as sex, age, genetic makeup, and environmental conditions [3]. Notably, asymmetry is a dominant characteristic, with studies showing that perfect symmetry is rare and septal deviation is a frequent finding in normal individuals [4]. While some individuals may lack one or both frontal sinuses entirely—a condition known as agenesis—such cases are relatively uncommon but relevant in clinical diagnosis and forensic evaluations [5]. Imaging modalities, especially radiographic tools like plain X-rays and computed tomography (CT), have enabled detailed examination of frontal sinus anatomy. Though CT offers superior resolution, plain digital radiographs (such as the Caldwell view) remain widely used due to their accessibility and cost-effectiveness, particularly in low-resource settings [6]. Digital radiographs are routinely employed in ENT and forensic practices to assess sinus health, detect infections, and compare anatomical patterns for identity confirmation [7]. The forensic utility of frontal sinus morphology is well-established. The sinus remains morphologically stable throughout adult life, is protected within the cranial vault, and can survive postmortem degradation, making it especially useful in disaster victim identification or in situations where DNA or dental records are unavailable [8,9]. Despite its relevance, region-specific anatomical data on frontal sinus characteristics are lacking for many Indian populations. Western Uttar Pradesh, with its ethnic and demographic diversity, remains underrepresented in morphometric sinus research. Establishing normative data for this population is crucial to enhance diagnostic accuracy in clinical radiology and reliability in forensic applications. This study therefore aims to evaluate the size, shape, symmetry, and anatomical variations of the frontal sinus using digital radiographs in individuals from Western Uttar Pradesh. By examining potential differences based on age and sex, and exploring forensic implications, this research contributes both clinically and scientifically to the field of radiological anatomy and identification science.
2. METHODS
2.1 Study Design
This study employed a cross-sectional, observational research design to assess the morphological features of the frontal sinus using digital radiographic imaging. The approach was quantitative in nature, enabling objective measurement of sinus parameters and their statistical comparison across demographic groups.
2.2 Study Setting and Population
The research was conducted in the Department of Radiodiagnosis at a tertiary-level diagnostic center in Western Uttar Pradesh, India. The population comprised individuals who underwent routine digital occipitofrontal (Caldwell view) skull radiography for non-traumatic indications.
2.3 Inclusion and Exclusion Criteria
Inclusion Criteria:
Exclusion Criteria:
2.4 Sample Size and Sampling Technique
A purposive sampling technique was used. Based on prior prevalence estimates of sinus asymmetry (~85%) and a desired confidence level of 95% with a 5% margin of error, the minimum required sample size was calculated as 196. To ensure statistical robustness, a total of 200 radiographs were selected and analyzed.
2.5 Ethical Considerations
Ethical approval was obtained from the Institutional Ethics Committee (IEC). All radiographic data were anonymized to protect patient confidentiality. Since archived diagnostic images were used without direct patient contact, written informed consent was waived under institutional guidelines.
2.6 Imaging Protocol
2.7 Data Collection Tools and Parameters
Measurements were performed using the digital ruler tool embedded in the radiographic viewing software. The following parameters were recorded for each radiograph:
To ensure consistency:
2.8 Statistical Analysis
Data were entered into SPSS version 25 and Microsoft Excel for analysis. The following statistical tests were used:
3. RESULTS
3.1 Demographic Characteristics
A total of 200 radiographic images were analyzed. The demographic distribution is summarized in the table below.
The demographic and anatomical distribution of the study participants revealed important insights into the morphological characteristics of the frontal sinus among individuals from Western Uttar Pradesh. Of the 200 subjects analyzed, females comprised 55% of the sample, while males accounted for 45%, ensuring a balanced representation for sex-based comparisons. In terms of frontal sinus symmetry, a significant proportion—72.5% of individuals—exhibited asymmetrical sinuses, whereas only 27.5% had symmetrical sinuses. This observation supports the established anatomical understanding that sinus asymmetry is a naturally prevalent feature among the population. Regarding nasal septal deviation, mild deviation was the most common finding, observed in 48% of participants, followed by none (26.5%), moderate (16.5%), and severe deviation (9%). The high prevalence of mild deviation aligns with general clinical observations, suggesting that minor structural shifts in the nasal septum are common and may not necessarily be pathological. When analyzing the shape of the frontal sinuses, the most frequent morphology observed was triangular (38.5%), followed closely by quadrangular (31%) and irregular shapes (30.5%). This variety underscores the anatomical uniqueness of frontal sinus patterns across individuals, which is a critical factor in forensic identification. Additionally, frontal sinus agenesis—the congenital absence of one or both sinuses—was present in 4.5% of subjects, consistent with reported global prevalence rates ranging between 3% and 10%. The majority of individuals (95.5%) had well-developed sinuses, further validating the reliability of frontal sinus morphology as a biomarker in both clinical and forensic applications.
3.2 Descriptive Analysis of Sinus Dimensions
Table 1: Mean Height and Width of Frontal Sinus (N = 200)
|
Measurement |
Mean (mm) |
Standard Deviation (mm) |
|
Left Frontal Sinus Height |
24.65 |
±4.83 |
|
Right Frontal Sinus Height |
24.27 |
±4.97 |
|
Left Frontal Sinus Width |
20.28 |
±4.03 |
|
Right Frontal Sinus Width |
19.53 |
±4.28 |
Interpretation:
3.3 Comparison by Sex
Table 2: Mean Frontal Sinus Dimensions by Sex
|
Measurement |
Male (mm) |
Female (mm) |
|
Left Frontal Sinus Height |
26.21 ± 5.18 |
23.43 ± 4.23 |
|
Right Frontal Sinus Height |
25.94 ± 5.10 |
22.88 ± 4.56 |
|
Left Frontal Sinus Width |
21.43 ± 4.11 |
19.34 ± 3.74 |
|
Right Frontal Sinus Width |
20.71 ± 4.20 |
18.53 ± 3.89 |
Interpretation:
3.4 Statistical Comparison Between Sexes
Table 3: T-Test Comparison of Sinus Dimensions by Sex
|
Measurement |
Male (Mean ± SD) |
Female (Mean ± SD) |
t-value |
p-value |
Significance |
|
Left Frontal Sinus Height |
26.21 ± 5.18 |
23.43 ± 4.23 |
-1.64 |
0.103 |
NS |
|
Right Frontal Sinus Height |
25.94 ± 5.10 |
22.88 ± 4.56 |
-1.28 |
0.201 |
NS |
|
Left Frontal Sinus Width |
21.43 ± 4.11 |
19.34 ± 3.74 |
1.49 |
0.138 |
NS |
|
Right Frontal Sinus Width |
20.71 ± 4.20 |
18.53 ± 3.89 |
1.48 |
0.140 |
NS |
NS: Not Significant (p > 0.05)
Interpretation:
3.5 Association Between Septal Deviation and Sinus Symmetry
Table 5: Chi-square Test – Septal Deviation vs Frontal Sinus Symmetry
|
Septal Deviation |
Symmetrical (n) |
Asymmetrical (n) |
Total (n) |
|
None |
24 |
29 |
53 |
|
Mild |
26 |
70 |
96 |
|
Moderate |
4 |
29 |
33 |
|
Severe |
1 |
17 |
18 |
|
Total |
55 |
145 |
200 |
Interpretation:
DISCUSSION
The present study examined the morphological characteristics of the frontal sinus using digital radiographs in individuals from Western Uttar Pradesh, with a focus on parameters such as symmetry, size, shape, septal deviation, and sex differences. The findings contribute to both clinical and forensic applications by providing population-specific data on sinus anatomy. One of the most significant observations was the high prevalence of asymmetrical frontal sinuses, noted in 72.5% of the sample. This finding is consistent with previous studies that have emphasized asymmetry as a common and natural anatomical trait. For instance, Camargo et al. (2007) reported similar asymmetry in their Brazilian population study, underscoring the uniqueness of frontal sinus morphology for forensic comparison [4]. The presence of asymmetry further validates its potential role in personal identification, as it adds individual-specific variation that remains relatively stable throughout adult life [2]. Another major finding was the variation in sinus dimensions between sexes, where males consistently exhibited larger frontal sinus height and width compared to females. Although the differences were not statistically significant in this study (p > 0.05), the trend is consistent with established literature on sexual dimorphism. Yadav et al. (2018) and Singh et al. (2022) both reported that frontal sinuses in males are generally larger, which is attributed to greater craniofacial growth driven by hormonal and genetic factors [7,10]. The lack of statistical significance in this study may be due to sample size, ethnic variation, or the use of 2D radiographs, which can limit volumetric precision compared to CT-based assessments. In relation to septal deviation, this study found that mild deviation was the most common, present in 48% of participants, while no deviation was seen in about 26.5%. However, there was no statistically significant association between septal deviation and frontal sinus symmetry (p = 0.849). This finding aligns with the work of Park et al. (2021), who also concluded that while septal deviation and sinus asymmetry may coexist, there is no strong evidence to support a causal relationship [11]. Thus, factors influencing sinus development are likely more genetic and developmental than mechanical. The distribution of frontal sinus shapes—triangular (38.5%), quadrangular (31%), and irregular (30.5%)—reflects the wide morphological variability reported in global literature. According to Sharma et al. (2017), sinus shape is a highly individualized characteristic, which enhances its utility in forensic settings [12]. This diversity in shape also reinforces the importance of having population-specific databases when using frontal sinus features for identification purposes. Furthermore, the study reported frontal sinus agenesis in 4.5% of participants, which aligns with global prevalence rates that typically range from 3% to 10% [5,13]. Agenesis was more commonly unilateral and did not significantly affect the broader applicability of sinus measurements. However, its presence should be documented carefully, as it can affect surgical planning and reduce forensic identification options in a small subset of cases. Although statistical significance was not achieved for several hypotheses, the observed trends are in agreement with previous anatomical and forensic studies [8,9]. Importantly, the use of digital radiographs (2D) instead of CT or MRI represents a low-cost and accessible tool that can still provide meaningful anatomical information in resource-limited settings, especially in rural and district hospitals [6].
CONCLUSION
This study provides valuable insights into the morphological variations of the frontal sinus among individuals from Western Uttar Pradesh, using digital radiography as an accessible and cost-effective imaging modality. The findings highlight that frontal sinus morphology is highly individualistic, with a high prevalence of asymmetry (72.5%), significant variation in shape patterns, and observable though not statistically significant sexual dimorphism, with males exhibiting larger sinus dimensions than females. The lack of a significant association between septal deviation and sinus symmetry suggests that such anatomical features may develop independently, likely influenced by genetic and developmental factors rather than structural nasal alignment alone. The presence of sinus agenesis in a small proportion (4.5%) of the sample is consistent with global norms and underlines the importance of considering such anatomical variants in radiological evaluations and forensic assessments. From a clinical perspective, understanding frontal sinus variability aids in accurate diagnosis of sinus-related disorders, surgical planning, and interpretation of imaging findings. From a forensic standpoint, the study reinforces the potential of frontal sinus morphology as a reliable marker for human identification, especially in mass disaster scenarios or in cases where traditional biometric identifiers are unavailable. Despite limitations such as the use of 2D imaging and a region-specific sample, this research contributes to the growing body of evidence supporting frontal sinus pattern analysis as a practical, low-cost, and reproducible method in both diagnostic radiology and forensic science. Future studies incorporating 3D imaging, larger sample sizes, and AI-based morphometric analysis are recommended to further validate and enhance the application of this method across diverse populations.
REFERENCE
Preeti Sahu*, Shubhanshi Rani, Comparative Study of Frontal Sinus Size in Different Populations Using Radiographs in Western Up Gonda, Int. J. Sci. R. Tech., 2025, 2 (11), 166-172. https://doi.org/10.5281/zenodo.17554042
10.5281/zenodo.17554042
