ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTEM. 



645 



The fissures which have just been mentioned are made use of 

 to map out the surface of the hemispheres into regions to which the 

 term lobes has been applied. This mapping is purely artificial and 

 has no clinical or pathological bearing; in many instances the lines 

 dividing the lobes are purely imaginary. However, anatomists are 

 accustomed to speak of six lobes: (1) frontal; (2) parietal; (3) 

 occipital; (4) temporal; (5) limbic, and (6) island of Reil. 



\Sutcus 



fornicaAt/5, 



Gyru 



s rec' 



Gyr.fusiforrniS 



Fig. 253. Longitudinal Section Through the Middle of an Adult 

 Jrain. The posterior portion of the thlamus, the crura cerebri, etc., 

 lave been removed, in order to expose the inner surface of the temporal 

 3be. ( EDINGEB. ) 



The island of Reil, or central lobe, is located at the bottom of 

 fissure of Sylvius. It is a portion of the cerebral cortex which 

 jverhung by the operculum. 

 The convolution of Broca is that portion of the inferior frontal 



nal). pr. 1. asc., An ascending branch of the prelimbic. paracentr., Paracen- 

 1 (posterior end of calloso-marginal). p.l., Post-limbic. ro, Rostral, ro. inf., 

 ferior rostral, p.-o., parieto-occipital. calc. ant., Stem of calcarine. calc. 

 t., Posterior part of calcarine. 1, 2, 3, 4, Places where annectent gyri occur 

 n calcarine and parieto-occipital fissures. t 3 , Third temporal, coll., collateral 

 or fourth temporal, h (placed on the fascia dentata) has the hippocampal fissure 

 just below it. 



Gyri FI, Marginal part of first frontal. C, callosal (gyrus fornicatus). H, 

 ippocampal. tine., Its uncus. h, Dentate. T 4 , Fourth temporal (fusiform 

 ule). T 5 , Fifth temporal or infracalcarine (lingual lobule): 

 cc, Corpus Callosum. spl., Its splenium. a, Its genu. r, Its Rostrum, fo, 

 ix. ft., Fimbria. 



