Clavicular nutrient foramina in dry human bones: surface distribution, regional localisation, and surgical relevance

Iatrogenic disruption of the clavicular nutrient artery during fracture fixation has been implicated in non-union. Population-specific data on nutrient foramen location are lacking for Indian skeletal collections. This study characterises clavicular nutrient foramina in an institutional dry bone series and benchmarks the findings against published international data.

121 unpaired dry adult human clavicles (60 right, 61 left) of unknown age and sex were examined. Foramen count, surface location (inferior/posterior/superior/anterior), total clavicular length (TL), distance of the foramen from the sternal end (DNF), and foraminal index (FI = DNF/TL × 100) were recorded. Segment classification (medial/middle/lateral third) was based on FI tertiles (0-33%, 33-66%, 66-100%), following the convention of Hughes [8], which allows comparison across bones of different total lengths. Categorical variables (foramen count, surface distribution) were compared between sides using Fisher's exact test; continuous variables (TL, DNF, FI) were compared using independent-samples t-tests (p < 0.05).

146 foramina were identified; 114 clavicles (94.2%) bore at least one foramen. Single foramina predominated (76.9%; 95% CI 68.6-83.5%); seven clavicles (5.8%) had none. Surface analysis revealed near-equal inferior (48.6%; 95% CI 40.7-56.7%) and posterior (49.3%; 95% CI 41.3-57.3%) distribution. Middle-third localisation was observed in 98.2% of foraminated clavicles (FI 33-66%). Mean TL was 138.5 ± 11.3 mm; mean DNF 72.1 ± 12.1 mm; mean FI 52.1 ± 7.9%. No significant bilateral asymmetry was detected in FI (p = 0.728) or DNF (p = 0.091).

This institutional dry bone series confirms middle-third predominance and identifies near-equal inferior and posterior surface distribution-a pattern also reported by a second independent South Indian study. These findings suggest that both inferior and posterior surfaces of the clavicular midshaft may warrant surgical awareness in this population. Direct clinical recommendations require validation through vascular or biomechanical studies.