Morphological Evaluation of Vascular Foramina in Dry Adult Human Calcanei: A Foraminal Index-Based Study From Western India.

INTRODUCTION AND AIM: The calcaneus is the largest tarsal bone and bears a major share of body weight during locomotion. Its vascular supply enters through small openings called vascular (nutrient) foramina, which lie on the medial, lateral, superior, and inferior surfaces. Knowledge of their number, location, and distribution is clinically relevant during calcaneal osteotomy, fracture fixation, and reconstructive procedures, as inadvertent injury to these vessels may precipitate delayed healing, non-union, or avascular necrosis. This study aimed to evaluate the morphology, number, location, and foraminal index (FI) of vascular foramina on the four anatomical surfaces of dry adult human calcanei from the Vadodara region. MATERIALS AND METHODS: A descriptive, cross-sectional, observational study was conducted on 40 intact, non-pathological dry adult human calcanei from the bone bank of the Department of Anatomy, Smt. B. K. Shah Medical Institute and Research Centre, Vadodara. Specimens with macroscopic damage or deformities were excluded. The total length (TL) of each calcaneus was measured between the most prominent anterior and posterior points using a manual vernier caliper of 0.02 mm precision. The distance from the most posterior point to the largest vascular foramen on each of the four surfaces was recorded as the largest medial surface foramen (LMS), largest lateral surface foramen (LLS), largest superior surface foramen (LSS), and largest inferior surface foramen (LIS). The foraminal index for each surface was calculated as (distance/TL) × 100. Each measurement was taken twice by the same observer, and the mean value was used to minimize observer bias. Descriptive statistics (mean, standard deviation, range, and percentage) were computed using Microsoft Excel (Redmond, WA: Microsoft Corp.). RESULTS: The mean total length of the calcanei was 74.87 ± 4.82 mm (range: 63.06-86.50 mm). At least one vascular foramen was identified on every specimen. Foramina were most frequently observed on the lateral surface (36/40, 90.0%) and the medial surface (35/40, 87.5%), followed by the inferior surface (29/40, 72.5%) and least often on the superior surface (13/40, 32.5%). The mean foraminal index was 54.84 ± 12.65% on the medial surface, 41.67 ± 11.86% on the lateral surface, 35.65 ± 13.38% on the superior surface, and 56.30 ± 22.55% on the inferior surface. The majority of medial (27/35, 77.1%) and lateral (29/36, 80.6%) foramina were located in the middle third of the calcaneal length, while inferior foramina were more widely scattered between the middle and distal thirds. CONCLUSION: Vascular foramina of the calcaneus exhibit considerable variability in number, location, and distribution. They are most consistent on the medial and lateral surfaces, where the bulk of the foramina cluster around the mid-calcaneal region. These observations may aid orthopedic surgeons in planning safe surgical corridors during calcaneal osteotomy, fracture fixation, and graft harvesting, thereby reducing the risk of vascular compromise and improving postoperative bone healing.