The significance of the amount of fluid surrounding the brain to the recognition of brain swelling (or atrophy) at autopsy: a new and routinely applicable method of diagnosing abnormal brain size.

A new method of measuring relative brain size (relative to the skull cavity) at autopsy is presented. It is convenient and accurate and may be applied almost routinely. It consists of measuring the volume of the brain and the fluids surrounding it. These two volumes together must equal the intracranial volume. An abbreviated method consists of relating the fluid volume to the brain weight. This abbreviated method should not be routinely relied on when the brain size deviates slightly from normal. A review of the pertinent literature shows that other existing methods of determining relative brain size are impractical. The significance of measuring peri-brain fluids at the time of brain removal has not been appreciated prior to this report.