[Jugular bulb position in the cranial base and its relation to cranial venous system]

Target CT images of 147 patients and digital subtraction angiography (DSA) images of 15 patients were examined to assess the relation between jugular bulb position and intracranial veins. First, relation of jugular bulb position to venous volume was examined from CT. The height of the jugular bulb was measured from the lower margin of the tympanic annulus to the apex of the jugular bulb by counting CT slices individually on the both side. The heights of the right and left jugular bulbs were 4.0 +/- 3.9 mm and 2.0 +/- 3.9 mm respectively, indicating that the right jugular bulb was higher than the left, consistent with previous reports. The depth of the sigmoid sinus sulcus, which may reflect the venous volume, was measured on the slice showing the internal auditory canal. The right side was 6.7 +/- 2.2 mm deep, while the left side was 5.3 +/- 2.0 mm in depth. These measurement also showed that the height of jugular bulb and depth of the sulcus of the sigmoid sinus were closely related. The jugular bulb was higher on the side with the deeper sigmoid sinus sulcus (correlation coefficient r = 0.73). Frontal head and neck angiography were performed after bolus injection of contrast medium. Angiographic images were modified and examined by means of a digital subtraction process. A result from angiography was consistent with the measurement of CT. The side with greater venous flow has the higher jugular bulb. And such difference in right and left venous flows was observed at and pproximately to the transverse sinuses.(ABSTRACT TRUNCATED AT 250 WORDS)