[Surgical anatomy of the sphenoid sinus--relationship to the internal carotid artery].
HRCT images in axial sections obtained from various otologic lesions were used for morphological studies of the sphenoid sinus. 412 cases including 224 males and 188 females, with an average age of 47.5 years were included in the study. None of the cases showed any evidence of sinus lesions. The internal carotid artery, at its close connection with the sphenoid sinus, was classified into five portions: I, the second turn; II, between the second and third turns; III, the third turn, IV, between the third and fourth turns, and V, ascending portion of the fourth turn. Protrusion into the sphenoid sinus was seen at I in 30.4% of the cases, at II in 39.8%, at III in 34.3%, at IV in 22.3%, and at V in 11.2%. The second turn, where the internal carotid artery emerges from the carotid canal in the petrous bone and turns upward into the cavernous sinus, showed the highest incidence of the carotid eminence. The incidence of protrusion increases as the sinus grows larger. The average distance between the natural orifice and the carotid canal was 19.3mm on the right and 18.9mm on the left. The distance between the posterior end of the nasal septum and the natural orifice was, on average, 3.6mm on the right and 3.6mm on the left.
Ikeda
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T
Department of Otolaryngology, Tokyo University Branch Hospital.
Iinuma
T
T
D000328:Adult; D002343:Carotid Artery, Internal / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013101:Sphenoid Sinus / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed