Proposed three-dimensional model of the orbit and relevance to orbital fracture repair.

PURPOSE: To describe the relationship of the orbital rim and depth in Far Eastern skulls by anatomical study, using morphometry to yield an octagonal three-dimensional model of the orbit. METHODS: Forty-one orbits of 21 Far Eastern skulls from the Department of Anatomy of St George's, University of London were included in this study. A morphometric study was conducted, measuring between eight reproducible orbital rim landmarks to yield perimeters, and from these landmarks to the optic canal to yield orbital depth. Orbital height and width were also recorded. Results were statistically analysed to look for evidence of gender variation or laterality before comparison with those from other ethnicities. The authors then present a method for three-dimensional description of the orbit. RESULTS: 67 % of orbits were male. Orbital height and width were significantly greater in males (34.6 ± 2.0 and 39.4 ± 1.7, vs. 32.5 ± 2.3 and 37.2 ± 2.4 mm). Orbital perimeter tended towards being larger in males (126.3 vs. 122.2 mm, p = 0.05), as was the angle between medial and lateral walls (50.1° ± 2.0°, vs. 47.9° ± 3.0°). CONCLUSION: This study has proposed a new method for describing the orbit using three-dimensional measurements, yielding clinically useful morphometric data. These results and model have applications in surgical navigation of the orbit, repair of fractures, and prediction of post-traumatic or surgical enophthalmos.