Compression of cerebral vessels by intracranial hypertension. I. Dural sinus pressures.

Abstract

In the monkey, sagittal sinus pressure is a complex function of cerebral blood flow and intracranial pressure; jugular vein pressure is a qualitative measure of cerebral blood flow. In the presence of intracranial hypertension, the response of anterior sagittal sinus pressure to blood flow changes is greatly exaggerated, but there is minimal communication of these large fluctuations in pressure to the transverse sinus and jugular vein. On the basis of these observations, we postulated compression of the sagittal sinus in response to increased intracranial pressure, and evidence is presented to localize maximum compression to the region of the interaural line. Reduction in diameter of cerebral vessels proximal to the sinus also appears to occur with intracranial hypertension, and ultimately, the dynamic interaction of these two factors is responsible for sagittal sinus pressure. In the end stage of cerebral decompensation, when intracranial and arterial tensions are equal, anterior sagittal sinus pressure also approaches the diastolic pressure, indicating nearly total collapse of the sinus.