Swelling of the Brain in Cases of Injury to the Head

Dehydration methods in the treatment of injury to the head have refocused attention on the subject of the water content of the brain and the partition of fluids within the cranial cavity. The total volume of the cranial content is fixed by the rigid confines of the bony cranial walls (Monroe-Kellie Doctrine).¹To maintain pressure equilibrium, a change in one component should be associated with a reciprocal change in some other.²The components involved are brain tissue, cerebral fluid and blood. The major factor is brain tissue, the chief subdivisions of which are solid matter (which is constant), intercellular water, intracellular water and parenchymatous hemorrhages. The cerebral fluid is divided into the subarachnoid and ventricular parts.³The extraparenchymatous blood includes that within the vessels outside the brain as well as that extravasated as subarachnoid, subdural or extradural hemorrhage.⁴ It has long been taught that with trauma