CONVOLUTIONS AND FISSURES OF SURFACE OF CEREBRUM.- 47 



a guide in your study of the surface of the brain. Only the 

 most important constant convolutions and fissures are therein 

 considered. The simple diagram of Ecker, of which they arc 

 reproductions, impresses itself more easily on the memory than 

 a representation of a real brain which shows all the shallower 

 fissures, which are inconstant, alongside the deeper and more 

 constant ones. . 



First, let us look up the fissure of Sylvius ; it divides the 



FIG. 28. 



Lateral view of the brain. The convolutions and lobes are marked in Roman letters, the 

 fissures and sulci in italics. (Alter Ecker.) 



greater part of the temporal lobe from the rest of the brain. We 

 can observe two branches a long anterior and a short posterior 

 and ascending branch. The mass of brain which lies at their 

 junction and covers the island is called the operculum. If we 

 separate those portions of the brain which surround the fissure 

 of Sylvius, as is done in Fi^ 1 . 27, the island lies in full view. We 



** O 



see that it is traversed by a deep fissure, passing obliquely 

 upward and backward, the sulcus centralis insulae, which 



