Morphological and Topographical Anatomy of the Nutrient Foramen in the Clavicle: A Cross-sectional Study

Introduction: The clavicle is the first bone to ossify during the fifth to sixth week of gestation and the last to complete the process. It develops from intramembranous ossification. Opinions vary regarding the significance of the nutrient foramen in the clavicle. Aim: To comprehensively understand the topographic anatomy of the nutrient foramen in adult human clavicles and its clinical importance. Materials and Methods: This cross-sectional study was conducted on 50 clavicles at the Department of Anatomy, Government Medical College Srinagar, from September 2023 to December 2023. The nutrient foramina were macroscopically observed using a magnifying lens to determine their number, location, direction, and patency. Vernier calipers were used to measure various foraminal dimensions, and the Foramen Index (FI) was calculated using the Hughes formula. The data was entered into Microsoft Excel 2016 and analysed using Statistical Package for Social Sciences (SPSS) version 22.0. Results: The study included 20 right-sided clavicles and 30 left-sided clavicles (total 50). Approximately 47 (94%) clavicles had a single nutrient foramen, while 3 (6%) clavicles had double nutrient foramina. All right-sided clavicles (100%) had a single nutrient foramen. Among the left-sided clavicles, 27 (90%) had a single foramen, and three clavicles (10%) had double foramina. Nutrient foramina were patent in 20 (100%) right-sided clavicles and 9 (30%) left-sided clavicles, meaning they were non-patent in 21 (70%) left-sided clavicles. Most clavicles had the nutrient foramen located on the posterior surface (42, 84%), while 8 (4%) had the nutrient foramen on the inferior surface. The nutrient foramen was noted in the middle third of the clavicle in about 35 (70%) clavicles, on the medial third in 10 (20%) clavicles, and on the lateral third in 5 (10%) clavicles. Conclusion: Nutrient foramina are predominantly located in the middle one-third region and on the posterior surface of the clavicle. As microvascular bone graft transfer is gaining popularity, surgeons must be familiar with the topography of the nutrient foramina of the clavicle to ensure successful bone grafting.