Distribution and morphometry of lingual foramina in dry mandibles

This study evaluated the prevalence, spatial phenotypic distribution, and linear morphometric distances of lingual foramina relative to vital surgical landmarks in dry human mandibles. Metric evaluations were conducted on 100 adult dry human mandibles ( n = 191 verified patent intraosseous canals) using a digital caliper (0.01 mm precision). Linear distances to the alveolar crest peak, mandibular base, mental spines, and mandibular foramen were recorded across four phenotypic patterns (Type I: Median only; Type II: Lateral only; Type III: Mixed; Type IV: Absence). Lingual foramina were present in 77.0% of mandibles, with multiple canal configurations predominating over solitary occurrences (56.0% multiple vs. 21.0% single). Median superior foramina were situated 13.82 ± 2.64 mm from the alveolar crest peak, whereas median inferior foramina were located 5.86 ± 2.45 mm from the mandibular base ( p < 0.001). Lateral foramina demonstrated robust bilateral metric symmetry across all evaluated landmarks (all p > 0.05, paired t-test). Spearman analysis revealed a significant inverse correlation between total foramen density and distance to the mandibular base (ρ = -0.418, p = 0.002). Type III (Mixed) patterns exhibited significantly constricted vertical bone boundaries (4.12 ± 1.85 mm, p < 0.05). An increase in lingual foramen density, especially in complex Type III patterns, significantly constricts the vertical safe bone corridor. Preoperative surgical planning should avoid standardized anatomical assumptions and prioritize patient-specific 3D radiographic evaluations to prevent severe neurovascular complications.