The contents of our skull and dura can be divided into three main compartments: brain parenchyma (which occupies a volume of approximately 1.4 L), spinal fluid (52-160 mL), and blood (150 mL). An increase in any of these three compartments, as per the Monro-Kellie hypothesis, will occur at the expense of the remaining two. In addition, intracranial compliance has been noted to decrease with rising pressure, thus causing further compromise in cerebral perfusion. The normal range of ICP has been reported to be 5 to 15 mm Hg.