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THE BRAIN 



named (i) temporal, (2) fronto- parietal, (3) frontal, and 

 (4) orbital. They are easily distinguished. 



The temporal operculum extends upwards over the insula 

 from the temporal lobe ; it forms the lower lip of the posterior 

 ramus of the lateral fissure (Fig. 152). 



The fronto-parietal operculum is carried downwards over the 

 insula to meet the temporal operculum. Its margin forms 

 the upper lip of the posterior ramus of the lateral fissure. 



Superior extremity are 



Inferior extremity area 

 Anterior central gyms i 

 Trunk area 



Central sulcus 



i 



j Sensory area 



Posterior central gyrus 



Face area 

 Posterior branch of lateral fissure 



Superior temporal gyrus Acoustic 



Visual area j 



Calcarine fissure 



FIG. 153. Lateral aspect of Left Hemisphere, showing 

 Sensory Areas. (After Elliot Smith. ) 



Motor and 



The frontal operculum is the small triangular piece of 

 cerebral cortex between the anterior ascending and horizontal 

 branches of the lateral fissure. It is sometimes termed the 

 pars triangularis. 



The orbital operculum is for the most part on the under 

 surface of the hemisphere. It lies below the anterior horizontal 

 limb of the lateral fissure, and passes backwards from the 

 orbital aspect of the frontal lobe over the anterior part of 

 the insula. 



Sulcus Centralis (O.T. Fissure of Bolando). The central 

 sulcus runs obliquely across the supero-lateral surface of the 



