[Anatomical relationship of the ethmoid-sphenoid areas to the optic canal and the internal carotid artery].

The anatomical relationships and morphologic features of the optic canal and the internal carotid artery to the lateral wall of the most posterior ethmoidal cell and the sphenoid sinus in 100 half-skulls swan middle-saggitally were investigated. The results showed: (1) The whole optic canals neighboured with the most ethmoidal cell in 39 cases, with the sphenoid sinus in 43 cases and with both of them in 18 cases; (2) The bulgings of the optic canal formed on the lateral wall of the most posterior ethmoidal cells and the sphenoid sinus were demonstrated in 48 and 47 cases respectively; (3) The marks of the internal carotid artery formed on the lateral wall of the sphenoid sinus were demonstrated in 53%-77% of all cases. The height and the thickness of the bony wall of the bulgings and marks of the optic canal and the internal carotid artery were measured. From our observation it was suggested that the variations of development and composition of the sphenoid-ethmoid sinuses, the bulging or mark of the optic canal and the internal carotid artery on the lateral wall of the most posterior ethmoidal cell and the sphenoid sinus might be the anatomical factors of severe complications in endoscopic ethmoid-sphenoid surgery.