CRANIAL AND SPINAL COMPONENTS OF THE CEREBROSPINAL FLUID PRESSURE-VOLUME CURVE

Abstract

A quantitative analysis of the contributions of the cranial and spinal compartments to the cerebrospinal fluid pressure-volume curve was made using dogs. The curve was determined by rapid continuous injection of fluid into the cisterna magna with simultaneous measurement of the pressure. Spinal block at the C 1 level was produced by inflation of an epidural rubber balloon allowing the recording of the pressure-volume curve for the isolated cranial system. By subtraction of the two curves obtained, the spinal pressure-volume curve could be calculated. 70 % of the variation in volume within the system was related to the spinal section and 30 % to the cranial section. The intracranial curve represents the effects on the fluid pressure of forced alterations in the volume of the intracranial vascular bed. The spinal compartment has a quantitatively defined and probably mechanically important function as an expansion vessel for the intracranial system.