CHAPTER XLI. 



THE CEREBRUM. 



FISSURES AND CONVOLU- PRESSURE SYMPTOMS 



TIONS. OF TUMORS. 



CEREBRAL LOCALIZA- CEREBRAL H1EMOR- 



TION. RHAGE. 



INTERNAL CAPSULE. LANDMARKS. 



ARRANGEMENT OF OPERATIONS. 



FIBRES. 



In connection with the cerebrum it is unnecessary, in a 

 work of this nature, to do more than briefly refer to 

 those portions, the knowledge of which is essential for the 

 proper understanding of cerebral topography and the 

 effects produced by tumors involving the brain. 



Fissures and Convolutions. (Fig. 11). Exam- 

 ining the lateral aspect of the cerebrum we find a fissure, 

 starting about half an inch behind the middle of the con- 

 vexity of the cerebrum at the longitudinal fissure, and 

 running downwards and forwards for about three and 

 three-quarter inches. This is the fissure of Rolando. Near 

 its termination another prominent fissure is seen, viz., the 

 fissure of Sylvius, which, running upwards and back- 

 wards, has a vertical limb, about half an inch in front of 

 the lower end of the Rolanderic fissure, and an anterior 

 limb, a little in front of the vertical. The rest of this fis- 

 sure, i.e., that portion behind the vertical limb, is the hori- 

 zontal limb. These fissures can always be identified on the 

 lateral aspect of the cerebrum, and are of great importance, 

 since the convolution in front of the fissure of Rolando, 

 viz., the ascending frontal, and that, behind the ascending 

 parietal are the chief parts of the brain associated with 

 motion, i.e., in which are situated the motor areas. In 

 front of the fissure of Rolando is the frontal lobe with its 

 three fissures the precentral, parallel to the fissure of 

 Rolando and marking off the ascending frontal convolu- 



