| Purpose To meet the needs of the clinical operation of orbital apex ,a research has been performed to explore a secure and easy operating route and a safe border for the en-doscopic operation of the orbital apex by means of the applied anatomy , sectional anatomy and imaging scans, and to provide the reliable anatomy data for the clinical diagnosis and endoscopic operation on the diseases of the orbital apex. Therefore, satisfactory operation effect is obtained and the complications are reduced. By comparison of the imaging and the sectional anatomic data on the orbital apex , we can evaluate the accuracy and value of the CT scan in visualizing this region in detail.Methods CD 30 adult cadaveric heads without any lesion were selected at random (male 21, female 9) and cut along the midsagittal plane, whose brain tissues were removed subsequently. According to the approach of transnasal endoscopic operation to the orbital apex ,we have observed and measured the distance from anterior nasal spine to the various structures of the orbital apex, the angles of the lateral deviation and elevation and the lateral deviate distance. Quantitative measurement was done for the length of the optic canal walls, the thickness of medial wall, the distance of the medial and lateral margins. The transverse and vertical diameter and the transverse area of the canal were also measured in the orbital part, middle part and intracranial part. The superior orbital fissure was measured in the length , distance of medial and lateral margins. Meanwhile , the distances of some nerves crossing the superior orbital fissure to the superior and medial walls of fissure and to the optic canal were measured respectively. (2)CT scan was performed on 9 adult cadaveric heads with continuous 2mm sections thickness through the Frankfurt-Virchow planeCFV plane) which was adopted as axial baseline or plane and coronal plane(vertical plane of the axial plane). The content of study was almost as same as the mentioned in the method CD except the angle of elevation and the lateral deviate distance of the structures in the orbital apex, the distances of some nerves crossing the superior orbital fissure to the superior and medial walls of fissure and to the optic canal. Besides, the angle between the optic canal and the sagittal plane was also measured.(3)The specimens were decalcified and cut by the baseline of CT scan. The measurement of the item mentioned in the method (2) was done exceptfrom the angle to the sagittal plane(SP).Result The mean distances from anterior nasal spine to the medial, lateral, superior and inferior walls of the optic canal in orbital part, middle part and intracranial part are 62. Olmm, 70. 04mm, 65. 02mm, 67. 15mm, 65. 60mm, 72. 36mm, 66. 52mm, 69. 54mm, 68. 23mm, 74. 60mm, 68. Olmm, 72. 67mm respectively. The mean angles of the lateral deviation and the elevation in orbital and intracranial medial margins of the canal are 9. 56?and 5. 34? 38. 77?and 34. 08?respectively. With the depth increasing, the angles gradually decreased. 11. 04mm and 0. 55 mm are the length of the medial wall of the optic canal and the thickness of medial wall in the middle part of the canal which are the longest among the canal walls and the thinnest in three parts of the medial canal wall respectively. 15. 86mm2 is the mean transverse area of the canal in middle part which is the narrowest among three parts of the canal. 17. 96mm, 30. 78mm,51. 23mm and 28. 98mm are the length, distance of medial and lateral margins and the shortest distance of the superior orbital fissure respectively. The mean angle to the sagittal plane is 40. 61 + 3. 49? There exists a good correlation between the data of the coronal scans and sections. The results of the sectional anatomy are the same as that of CT scans on the whole.Conclusion (1)Allow for the orbital apex, the transnasal endoscopic operation must be performed near the middle line. With the depth increase, the angles must be decreased relatively. (2)For the decompression of the optic canal, it is imp...
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