Parvindokht Bayat; Mahdie Bagheri; Ali Ghanbari & Amir Raoofi

Summary

The occipital condyle (OC) is an important area in craniovertebral surgery, but its anatomical features and the procedures concerning the OC have not been studied in detail yet. The aim of this study was to revisit the anatomy of the occipital condyle region and assess variations of the surrounding structures. Observations, on fifty dry skulls (dried specimens, 100 sides) and determined of condyle measurements. The mean length, width and height of occipital condyle were found to be 19.43±3.27 (right), 19.28±3.57 (left), 9.21±1.97 (right) 9.40±1.87 (left), 7.21±1.9 (right) and 7.33±2.74 mm (left), respectively. There were significant differences between right and left occipital condyles. The mean anterior intercondylar distance and posterior intercondylar distance were measured as 15.39±7 and 35.60±8.4 mm, respectively. Variations of occipital condyle shapes were kidney like (34.4%), S-like (25.6), triangular (13.3%) oval (10.0%), ring like (7.8%), eight like (6.7%) and deformed (2.2%) respectively. The condylar fossa presented in 60% of dry skull, 24% in right side and 36% in left side and also the condylar foramen was found in 60% of the specimens studied. There was no relation between the circumference of the head and the length of OC but we found relation between the circumference of the head and the width of OC (0.527) and foramen magnum circumference (0.433). The OC and FM are the main bony structures obstructing the surround of the brainstem. The differences in the size and the shape of occipital condyle have some differences and also similarities among racial subgroups. The posterior condylar vein may act asymmetrically. The correlation of the size of foramen magnum with the width of occipital condyles shows the importance of occipital condyle for lateral movements besides antero-posterior movements.

KEY WORDS: Skull base; Foramen magnum; Occipital bone; Iran.

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