A morphometric evaluation of the optic canal: Comparative study between computerized tomographic study and direct anatomic study

Abstract

The objective of this study is to probe into the normal anatomy of the optic canal by comparison of dry skull and computed tomography (CT) images of live subjects. Materials and Methods: The optic canals of 107 normal subjects were examined by thin layer CT scan images in axial and coronal sections. 25 dry skulls were examined by using sliding Vernier caliper. The width, height of optic canal in both opening (cranial and orbital side) were measured. The medial, lateral walls (LWs) of optic canal were also measured. By using mathematical formula, the area of optic canal was calculated. Student's t-test was applied to compare the results statistically. Results: The height of optic canal at orbital and cranial opening in both CT and direct study was 4.12 ± 0.63 mm, 3.6 ± 0.76 mm and 5.7 ± 0.76 mm, 5.17 ± 0.81 mm, respectively. The width at orbital and cranial opening in both CT and direct was 2.98 ± 0.56 mm, 4.59 ± 0.83 mm and 4.74 ± 0.47 mm, 5.48 ± 0.76 mm, respectively. The length of medial and LW in both CT and direct study was 10.63 ± 1.72 mm, 9.2 ± 1.33 mm and 9.1 ± 1.46 mm, 8.66 ± 1.31 mm, respectively. The area was 1.43 cm΂ in direct study and in CT study it was 1.19 cm΂. Conclusion: Given parameters may be helpful for surgeons to plan the proper way to approach the optic canal.