Glossary term:

Intracranial pressure

This is the effective pressure within the tissues inside the skull, principally the brain.
In any organ of the body blood flows in through arteries, passes through a capillary bed and drains back out into veins. Blood will spurt out of a cut artery under high pressure. Blood will flow out of a vein under low pressure. Between these inflow and outflow channels the pressure averages at a level which, in effect, represents what is left of the main arterial pressure, as it dissipates through the brain’s capillary bed. If the brain’s venous drainage reduces, for example when lying down from a standing position, then the intracranial pressure will rise. Following brain surgery, therefore, patients are often nursed in a partially propped-up position. Read more