The Pressure-Volume Curve of the Cerebrospinal Fluid Space in Dogs

The cerebrospinal fluid pressure-volume curve was determined by measuring the pressure response to rapid injection of fluid into the cisterna magna of dogs, by means of a constant flow infusion pump. The shape of the curve is complex, with two plateaus at the levels of the venous and arterial pressures, respectively. The slope dP/dV is referred to as the elastance of the system (mmHg/ml). The elastance has a low value in the normal pressure range and shifts at a fluid pressure of about 15 mmHg to a value approximately 20 times higher, with a relatively minute change in the volume of the system.