Intracranial volume, brain volume, reserve volume and morphological signs of increased intracranial pressure – A post-mortem analysis

In a series of 93 unselected forensic autopsies of adults the following volumes were measured: skull volume by filling a sac of synthetic material with water, placed intracranially, after removal of the brain and brain volume by its water displacement. Objective was to demonstrate if generally is there a relation between reduced difference of skull volume minus cerebral volume (“reserve volume” = RV, predominantly identical with cerebrospinal fluid compartment) and the presence of pressure marks (grooves) on the basis of temporal lobes (uncal grooves) and cerebellum (cerebellar cone). These alterations in post-mortem examination were usually regarded as signs of increased intracranial pressure during life. The obtained data were presented in diagrams.Most of the intracranial volumes were in the range 1200–1600 ml and brain volumes in the range 1200–1500 ml. The actual brain volume can be estimated by the multiplication brain weight ∗ 0.957. The RV in most cases was situated between 25 and 150 ml, corresponding 2–10% of the cranial cavity – increasing with increasing age of the persons.Clear uncal grooves (less distinct: cerebellar grooves) relate to significant decrease of the RV and the conclusion seems acceptable that this is indicative for intracranial displacement during life and is therefore an indirect sign of – at least local – brain swelling and increased intracranial pressure. However, to provide a well-founded basis for such a conclusion in a case under investigation a (semi quantitative) graduation of the intensity of such actual grooves seems to be recommendable.