AX ATOM V AND PHYSIOLOGY OF NERVOUS SYSTEM. 



64 H 



cerebellum; (3) the fissure of Sylvius; (4) fissure of Rolando; (5) 

 parieto-occipital fissure. 



As previously stated, the great longitudinal fissure runs antero- 

 posteriorly to separate the two hemispheres of the brain. 



At its posterior end and at right angles to it lies the great 

 transverse fissure. By it the posterior portion of the cerebrum is 

 separated from the cerebellum. 



The fissure of Sylvius begins at the base of . the brain at the 

 anterior perforated space. It passes outward to the external sur- 



Fig. 251. Lateral Aspect of Brain. (EniNGER.) 



The gyrus centralis anterior is the ascending frontal convolution. The gyrus 

 centralis posterior is the ascending parietal convolution. Sulcus centralis, fissure 

 of Rolando. 



face of the hemispheres, where it divides into two branches. The 



J" 1 iranch passes upward (ascending limb) ; the other, a larger one, 

 nearly horizontally backward (horizontal limb). 

 The fissure of Rolando commences at the great longitudinal 

 e, half an inch behind its middle point, measuring from the 

 lla to the external occipital protuberance. It runs downward 

 and forward to terminate a little above the horizontal limb of the 

 ure of Sylvius. 



The parieto-occipital fissure commences about midway between 

 posterior extremity of the brain and the fissure of Rolando and 

 s downward and forward for a variable distance. 



