Occipital Condyle and Cranial Base Morphometry in a Central Indian Population: Implications for Craniovertebral Junction Surgery and Osteological–Radiological Comparability

Abstract

Background: The occipital condyle and cranial base angle are critical to craniovertebral junction (CVJ) surgical planning, yet population-specific normative data are lacking for Central India, and few studies directly compare osteological and radiological measurement of these structures. Objective: To establish occipital condyle and cranial base angle norms in a Central Indian population and evaluate bilateral symmetry, osteological-radiological comparability, and measurement reliability. Methods: 220 specimens (110 dry skulls, 110 CT scans; 110 male, 110 female) were measured for occipital condyle length, width, intercondylar distance (both arms), and cranial base (basion-sella-nasion) angle and clivus length (CT arm only). Side comparisons used paired t-test/Wilcoxon signed-rank; arm comparisons used independent-samples tests; intra-observer reliability used the intraclass correlation coefficient (ICC). Results: No significant right-left asymmetry was found for occipital condyle length or width (p>0.05). Dry-skull and CT-based measurements did not differ significantly at the group level for any shared parameter (all p>0.05). Cranial base angle averaged 130.86±4.50° and did not correlate with foramen magnum dimensions (all |r|<0.16). Intra-observer reliability was excellent (ICC=0.99). Conclusion: Occipital condyle and cranial base dimensions in this population support existing international surgical safe-zone guidance for the transcondylar approach, and osteological and radiological measurement are comparable at the population level, though not established as equivalent for any individual case.