Fig. 19. Cranio-Cerebral Topography. 



Tlie bars of A. Koehler's "Craniencephalometer" are dark red; Brain pink, 



diagrammatic. 



For practical purposes it is very important to know the surface markings 

 for the different parts of the hemisphere. By such knowledge a diagnosis can 

 be made of: "Which cortical region is affected in any particular injury of the Skull?" 

 On the other hand, functional disturbances may indicate disease of a certain part 

 of the Corte.N. which may require operation ; by this knowledge of surface markings 

 the surgeon is enabled to find the seat of the lesion. 



Generally speaking it is sufficient to determine the position of the Fissures 

 of Rolando and Sylvius because the most important centres are situated in the 

 neighbourhood of these fissures (cf. Fig. 3, 5) further with these landmarks other 

 sulci and fissures can be easily marked out. 



Many methods have been devised, some requiring special instruments. 

 Koehler's method is simple and reliable. 



Cf. Fig. Three lines are necessary. 



1. A Sagittal line extending from the root of the nose to the External 

 Occipital Protuberance. 



2. A Vertical line through the Anterior Border of the External Auditory 

 Meatus. 



3. A second Vertical line parallel to the former through the Posterior 

 Border of the Mastoid Process. 



P>om the point where the last mentioned line meets the Sagittal line another 

 line is drawn downwards and forwards to a point situated midway between the 

 junction of the middle with the lower thirds and the mid-point of the first Vertical Line. 



This point corresponds to the lower end of the ROLANDIC Fissure, the 

 upper end of which lies at the junction of the line drawn from the Sagittal Line. 



The Fissure of SYLVIUS lies Vs ii^ch below the inferior end of the Fissure 

 of Rolando. About 2 V-, inches above the Zygoma the Short Anterior and Long 

 Posterior Limbs of this fissure begin. Another excellent method of marking out 

 the Fissures of Rolando and Sylvius, devised by Kroenlein, is described 

 in Pis'. 1 8. 



