Dilatations of the Cavity of the Septum Pellucidum and Cavum Vergae: Report of Cases

Abstract

Introduction Rarity or even relative rarity as a quality of any pathological condition has ever served to interest physicians and surgeons. Particularly is this true when the unusual condition may lend itself to treatment or lead to speculation regarding etiology, as is the case with dilatations of the cavity of the septum pellucidum and cavum vergae. Dilatations of these cavities have long been known. Sylvius mentions dilatations of the cavity of the septum pellucidum several times. In a recent excellent contribution on this subject, Dandy (1) points out Verga9s priority claim to discovery and description of the cavity now known by his name—the cavum vergae. As we shall point out later, embryologically these two cavities are really one, and only chance variations in development may separate them. From a clinico-pathological point of view, the dilatations of the cavity of the septum pellucidum and the cavum vergae may be divided into three groups: (1) the non-communicating type, in which the walls of the dilated cavity are intact and a closed cavity results (Fig. 1); (2) the communicating type, in which there is communication with the adjoining third or lateral ventricle as a result of rupture of the walls when the fluid pressure from within reaches a certain point (Fig. 2); (3) secondary or “acquired” dilatations of the communicating type as a part of a later developing or superimposed hydrocephalus from whatever cause (Figs. 3–6).