[Surgical anatomy of the sphenoid sinus--development and intersinus septum]

High-resolution CT images in axial sections obtained from various otologic lesions were used for morphological studies of the sphenoid sinus. 412 subjects, 224 males and 188 females with an average age of 47.5 years, were included in the study. None of the subjects showed any evidence of sinus lesions. By classifying them into four types, the incidences were: conchal type, 1.2%, and postsellar type, 58.2%, respectively. Of surgically important classification of various septae, the incidences were: transverse, 10.9%, medial, 9.4%, frontal lateral, 14.1%, lateral sagittal, 41.5%, and intersinus, 95.1%, respectively. The intersinus septum, seen in 95.1%, pointed toward the carotid canal in 61.1% (right, 33.1; left, 28.0%). In 80% of the subjects, the sphenoid sinus had extended into the bilateral lesser wings and was in contact with the optic canal.