ABSTRACT
The variations of the sigmoid sinus were studied in 50 Korean adults (average age 67). The classification of the shape and a measurement of the diameters of the sinus were done and the morpological. 1. The shape was classified into 4 types, and the round type was the most common in both sides. S shaped type was below 10% in both sides. 2. The breadth was regular in 54% of the right and in 70% of the left sinuses. According to the breadth change, the shape was classified into 4 shapes. 3. The average diameter was 8.6mm on the right side and 7.2mm on the left side. 4. Symmetry was present in 16% of all. 5. The right transverse sinus was absent in 1 case (2%) and the superior petrosal sinus did not open into the sigmoid sinus in 2 cases (4%). 6. Petrosqamous sinus was observed in 16%.