Variations of the Occipital Sinus in Korean Adults

The variations of the occipital sinus were studied in 50 Korean adult cadavers. The morphology of the sinus was classified into 5 types accordingo to its number and the connection with the marginal sinus. These results were compared with the data of the occipital sinus of bones (Sir and Chung, 1907). And the opening of the occipital sinus in the confluens sinuum was observed. 1. A single small occipital sinus was found in 40%. Single occiital sinus with two large marginal sinuses was observed in 8%. The single sinus with a left marginal sinus (6%) and with a right marginal sinus(4%) were present. Double occipital sinuses were observed in 10% of the cadavers. No occipital sinus was discernible in 32%. 2. There were 39 openings of the occipital sinus including the double sinuses. The occipital sinuses communicated with the confluence sinuum in 35 cases (89.7%), with the straight sinus in 5.1% and with the right or left transverse sinus in 1 case, respectively. The openings in the confluens sinuum were found on the left side(51.3%), on the right side (10.3%) and in the center(28.2%). 3. The diameters of the occipital sinus were variable according to the connection with the sigmoid sinus. 4. The difference was found between the data of the morphological types of the occipital sinus that were studied in cadavers and in dry bones.