A Model of the Extradural Space and a Reappraisal of the Extradural Space Pressure

Abstract

A model is described which was used to study the genesis of the pressure in the extradural space. It consists of a Perspex outer tube, with perforations covered with rubber septa to allow the insertion of needles, and Paul's tubing on the inside, representing the dura mater. The Paul's tubing is filled with water through a constant head of pressure apparatus. The response of the model to the insertion of an extradural needle and the reproduction of various clinical phenomena are described. The pressure in the extradural space is discussed in relation to the performance of the model.