Comparative Study of Frontal Sinus Size in Different Populations Using Radiographs in Western Up Gonda

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:

• Individuals aged 10 to 60 years
• Availability of high-quality digital occipitofrontal radiographs
• No history of craniofacial trauma, sinus surgery, or congenital craniofacial anomalies

Exclusion Criteria:

• Poor image quality or improper head positioning
• Known cases of frontal sinus pathology or systemic syndromes affecting craniofacial development
• Individuals with previous frontal sinus surgical interventions

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

• Radiographic View Used: Occipitofrontal (Caldwell view)
• Imaging Modality: Digital radiography
• Equipment: Standard digital X-ray machine with PACS (Picture Archiving and Communication System)
• Head Positioning: Standardized alignment ensuring accuracy and consistency across samples

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:

• Frontal sinus height (left and right)
• Frontal sinus width (left and right)
• Symmetry status (symmetrical/asymmetrical)
• Septal deviation (none, mild, moderate, severe)
• Sinus shape (triangular, quadrangular, irregular)
• Presence of agenesis (unilateral or bilateral absence)

To ensure consistency:

• All measurements were performed twice by the primary investigator.
• 10% of images were independently reviewed by a second radiologist.
• Inter-observer reliability was confirmed with a Cohen’s Kappa > 0.80.

2.8 Statistical Analysis

Data were entered into SPSS version 25 and Microsoft Excel for analysis. The following statistical tests were used:

• Descriptive statistics (mean, standard deviation, frequency, percentage) for frontal sinus dimensions and demographic variables.
• Independent samples t-test to assess sex-based differences in sinus dimensions.
• Chi-square test to analyze the association between septal deviation and sinus symmetry.
• Significance Level: A p-value of < 0.05 was considered statistically significant.

3. RESULTS

3.1 Demographic Characteristics

A total of 200 radiographic images were analyzed. The demographic distribution is summarized in the table below.