400 



THE 





divide the hemispheres into districts termed Mes, and, for 

 that purpose, certain fissures and sulci are chosen which are 

 termed interlobar fissures and sulci \ they are the following : 



1. The lateral fissure (O.T. Sylvian). 



2. The central sulcus (O.T. fissure 



of Rolando). 



3. The parieto-occipital sulcus. 



Anterior central gyrus 

 Inferior precentral sulcus , 



Superior frontal sulcus 

 Middle frontal sulcus i 

 Superior frontal gyrus 



Middle frontal gyrus 



4. The collateral fissure. 



5. The circular sulcus (O.T. limiting 



sulcus of Reil). 



Anterior central gyrus (lower buttress) 



Anterior central gyrus (upper buttress) 

 i Central sulcus 



Inferior post -central sulcus 



Supra-marginal gyrus 



Interparietal sulcus (prop 

 Angular gyrus 



Pronto-marginal 

 sulcus 



Inferior frontal sulcus 

 Inferior frontal gyrus 



Pars orbitalis 

 Lateral fissure (ant. horiz. branch) 



Pars triangular 



Lateral fissure 



Pars basilaris 

 Sulcus diagonalis 

 Lateral fissure (posterior branch) 



Superior temporal gyrus 



Superior temporal sulcu 



CE 



fissur 

 bram 



I Sulcus occ 

 | paramedia! 

 I Lunate sulcus 



Middle temporal sulcus 

 Middle temporal gyrus 



| Lateral occipital sul 



nferior temporal gyrus 



Posterior central gyrus Superior temporal sulcus 



FIG. 152 Supero-lateral aspect of Left Hemisphere (semi-diagrammatic). 

 The orbital surface is shaded. 



The lobes which are mapped out by the fissures mentioned 

 are (i) the frontal; (2) the parietal; (3) the occipital; (4) 

 the temporal; (5) the insula. To them may be added a 

 sixth lobe, in no way related to the interlobar fissures, viz., 

 the olfactory lobe. 



Fissura Lateralis (O.T. Sylvian). The lateral fissure is 

 the most conspicuous fissure on the surface of each cerebral 

 hemisphere. It is composed of a short main stem, from the 

 lateral extremity of which three branches radiate. The stem 

 is placed on the inferior surface of the cerebrum (Fig. 138). 



