European Journal of Cardiovascular Medicine

The mandibular foramen is a vital anatomical landmark located on the medial surface of the ramus of the mandible, serving as the entry point for the inferior alveolar neurovascular bundle, which travels through the mandibular canal to supply the lower teeth, jawbone, and associated soft tissues [1,2]. Given its clinical significance, particularly in dental and oral surgical procedures, accurate localization of this foramen is essential for effective regional anesthesia, most notably the inferior alveolar nerve block (IANB) [3].

The IANB remains a widely practiced technique in dentistry and maxillofacial surgery to achieve anesthesia of the mandibular arch. However, failure rates of 15–20% have been reported in clinical settings, primarily due to anatomical variations or inaccuracies in needle placement [4,5]. Contributing factors such as age, sex, ethnicity, and individual developmental differences can lead to deviations in the foramen’s position, which in turn may result in inadequate analgesia, patient discomfort, or iatrogenic complications including hematoma formation and neurovascular injury [2,5].

Although advances in radiological imaging such as CBCT and MRI have improved anatomical visualization, many clinicians continue to rely on conventional surface landmarks and generalized anatomical averages during anesthetic procedures. As a result, morphometric studies of the mandibular foramen remain crucial to refine anatomical knowledge, guide clinical practice, and account for population-specific variations [1,3,4].

Previous investigations have described the position of the mandibular foramen relative to neighboring landmarks such as the anterior and posterior borders of the ramus, mandibular notch, and mandibular base, but significant variability persists across different populations [2,5,6]. Therefore, this study aims to evaluate the morphometric location of the mandibular foramen in a sample of dry adult mandibles and discuss its clinical implications in improving the success rate of IANB procedures.

The present study aims to assess the morphometric location of the mandibular foramen in adult dry mandibles and to explore its clinical significance for improving the precision of the IANB procedure.

Study Design and Setting

This was a descriptive, cross-sectional morphometric study conducted in the Department of Anatomy at Shri Vasantrao Naik Government Medical College (VNGMC), Yavatmal, Maharashtra, over a period of 17 months, from August 2021 to December 2022.

Sample Size and Sampling Technique

A total of 100 mandibular sides from 50 adult dry human mandibles were included in the study. The mandibles were obtained from the departmental osteology collection and were of unknown age and sex. Only mandibles that were fully ossified, intact, and without any pathological deformities were selected through purposive sampling. Damaged or deformed specimens were excluded.

Morphometric Parameters Measured

Using a digital Vernier caliper (accuracy 0.01 mm), the following parameters were measured bilaterally:

MF–AB: Distance from the mandibular foramen to the anterior border of the ramus

MF–PB: Distance from the mandibular foramen to the posterior border of the ramus

MF–MN: Vertical distance from the mandibular foramen to the mandibular notch

MF–MB: Vertical distance from the mandibular foramen to the base of the mandible

Each measurement was taken three times by two independent observers, and the average value was recorded to minimize observer bias.

Data Analysis

The collected data were entered into Microsoft Excel and analyzed using SPSS version 25.0. Descriptive statistics were calculated for each parameter, including mean, standard deviation (SD), minimum, and maximum values. An independent t-test was used to compare left and right side measurements, and a p-value of <0.05 was considered statistically significant.

Ethical Considerations

As this study was conducted on archived dry human mandibles, no direct human or animal participants were involved. However, approval for conducting the study was obtained from the Institutional Ethics Committee of VNGMC Yavatmal.

A total of 100 mandibular sides were analyzed in this morphometric study, comprising 50 left and 50 right sides from adult human mandibles. The anatomical landmarks measured included the distance from the mandibular foramen to the anterior border of the ramus (MF–AB), posterior border of the ramus (MF–PB), mandibular notch (MF–MN), and mandibular base (MF–MB).

The overall descriptive statistics for all measured parameters are summarized in Table 1. The mean distance from the mandibular foramen to the anterior border of the ramus (MF–AB) was 15.24 ± 2.11 mm, and to the posterior border (MF–PB) was 11.76 ± 1.94 mm. The mean vertical distance to the mandibular notch (MF–MN) measured 20.32 ± 2.38 mm, while the distance from the foramen to the mandibular base (MF–MB) was 21.85 ± 2.60 mm.

Table 1. Descriptive Statistics of Mandibular Foramen Measurements (n = 100)

 Figure 1. Descriptive Statistics of Mandibular Foramen Measurements

A side-wise comparison between the left and right mandibular sides is presented in Table 2. The mean measurements of all parameters were found to be comparable between sides. Specifically, the MF–AB distance measured 15.12 ± 2.10 mm on the left and 15.36 ± 2.13 mm on the right. Similarly, MF–PB was 11.82 ± 1.88 mm on the left and 11.70 ± 2.01 mm on the right. The MF–MN and MF–MB distances also showed minimal variation between sides. Statistical analysis using the independent t-test revealed no significant differences between the left and right sides across any of the measured variables (p > 0.05 for all), confirming bilateral symmetry of the mandibular foramen location in this sample population (Table 2).

Table 2. Side-wise Comparison of Mandibular Foramen Measurements (Left vs Right)

No statistically significant difference was observed between left and right mandibular sides (p > 0.05 for all measurements), as analyzed using the independent t-test.

Figure 2.Side-wise Comparison of Mandibular Foramen Measurements

These findings highlight the consistent morphometric positioning of the mandibular foramen, with the majority of values indicating a location posterior to the midline of the ramus width and superior to the midpoint of the ramus height. Such precision in localization holds clinical importance, particularly in improving the accuracy and efficacy of inferior alveolar nerve block (IANB) procedures.

The present study aimed to determine the morphometric location of the mandibular foramen and its clinical implications for the accurate administration of the inferior alveolar nerve block (IANB). Accurate localization of the foramen is essential for effective regional anesthesia in dental procedures, but anatomical variability poses a frequent challenge for clinicians [6,9].

In this study, the mean distance from the mandibular foramen to the anterior border of the ramus (MF–AB) was 15.24 ± 2.11 mm, and to the posterior border (MF–PB) was 11.76 ± 1.94 mm. These values are comparable to those reported in previous morphometric analyses conducted in Indian [6] and Saudi pediatric populations [7], highlighting consistency in foramen placement across demographic groups. The vertical distances MF–MN (20.32 ± 2.38 mm) and MF–MB (21.85 ± 2.60 mm) also align with the findings of Insha et al. [6] and Guzmán et al. [9], who emphasized the relevance of vertical dimensions in minimizing the risk of failed or misplaced nerve blocks.

Importantly, no statistically significant differences were observed between the left and right sides (p > 0.05), suggesting a high degree of bilateral symmetry in foramen positioning. This anatomical symmetry is consistent with findings from AbdElrahman et al. [8] in a Sudanese population and reinforces the reliability of using contralateral landmarks when localizing the foramen during unilateral procedures.

The mandibular foramen in our sample was generally located posterior to the midpoint of the ramus width and above the midpoint of the ramus height. This relative positioning supports a more targeted and predictable approach to needle placement for IANB and may help reduce procedural failure, particularly in patients with anatomical variations, developmental abnormalities, or structural alterations due to trauma [6,11].

The use of dry adult mandibles provided high precision in identifying osseous landmarks, but the absence of soft tissue and demographic details limits the extrapolation of these results to live clinical populations. Additionally, the lack of sex and age categorization in our sample may overlook important anatomical differences reported in studies utilizing CBCT in pediatric and adult cohorts [7,8,10]. Furthermore, variations in the mandibular lingula and canal morphology, which can influence the foramen’s accessibility, were not assessed in this study but have been described in recent literature [11].

Despite these limitations, our findings align with those of multiple global studies and strengthen the evidence base regarding the morphometric characteristics of the mandibular foramen. Future research involving cone-beam computed tomography (CBCT) in living subjects is recommended to validate these observations, explore age and sex-related variations, and optimize clinical strategies for both surgical and anesthetic applications.

This morphometric study provides valuable insights into the anatomical positioning of the mandibular foramen, a critical landmark for administering the inferior alveolar nerve block (IANB). The foramen was consistently located posterior to the midpoint of the mandibular ramus width and superior to the midpoint of the ramus height, with no statistically significant differences between left and right sides. These findings highlight the relative symmetry and predictability of the foramen’s location in adult mandibles. Accurate knowledge of these measurements can significantly enhance the success rate of IANB and minimize complications.

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