Intracranial pressure

Dr Craig Hacking and Dr Bruno Di Muzio et al.

The intracranial pressure (ICP) represents the pressure exerted by the essentially incompressible components (brain tissue and interstitial fluids, blood and CSF) contained within the rigid confines of the skull 1-3.

ICP has a normal pulsatile variation derived from the transient changes in blood volume associated with the cardiac and respiratory circles 2.

Under a dynamic equilibrium, the normal range of CSF pressure is between 5 and 15 mmHg (7.5-20 cm H2O) 2-4. In children, however, there are different upper tolerated limits, defined for age groups - in general the normal interval is considered to be 3 to 7 mmHg for young children and 1.5 to 6 mmHg for term infants 4.

The Monro-Kellie hypothesis explains the pressure-volume relationship that aims to keep this dynamic equilibrium among the essentially non-compressible components inside the skull 1.

Changes in ICP have been shown to depend on four variables:

Physiological elevations of ICP can occur briefly (e.g. due to coughing, head-down tilt, and neck veins compression). As they are equally distributed throughout the spinal axis and last for a short period of time, they do not cause neurological damage 2.

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Article information

rID: 37054
Section: Anatomy
Synonyms or Alternate Spellings:
  • Intracranial pressures

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