Fig. 2

A Waveform and hierarchies of pressures in the cerebral vasculature at baseline ICP. Systemic arterial pressure (P_A) with systolic peaks around 120 mmHg is followed by cerebral arteriolar pressure (P_ARL) which is somewhat lower. Pressures in the capillary bed (P_C) and veins (P_V) is markedly lower and displays a flattened waveform typical of capillary and venous circulation. Pressure in the sagittal sinus (P_SSS) is the lowest in the intracranial space and is typically lower than ICP. B Waveform and hierarchies of pressures in the ventricles (ICP_VEN), brain (ICP_BR), and subarachnoid space (ICP_SAS). At baseline, ventricular pressure is slightly higher than brain intraparenchymal pressure preventing ventricular collapse. Subarachnoid pressure (ICP_SAS) is slightly lower than both ventricular and brain intraparenchymal pressure, allowing flow of both ventricular CSF and cerebral interstitial fluid into the subarachnoid space