284 



PRACTICAL ANATOMY". 



convolutions are separated by the stellate fissure. By 

 separating the frontal and temporo-sphenoidal . lobes, the 

 island of Eeil is exposed. It consists of a cluster of 

 five or six convolutions projecting from the bottom of the 

 fissure of Sylvius. 



The inner surface of the cerebral hemisphere is flat 

 and presents five principal convolutions. First, the 

 marginal convolution skirts the free border of the longi- 



Gca 



FIG. 123. LEFT HEMISPHERE OF HKAIN, SHOWING ISLAND OF REIL. 



In, island of Reil ; Sc, sulcus centralis ; Gca. Gcp, gyrus centralis, anterior and posterior ; 

 Fop, fissura parieto-occipitalis. 



tudinal fissure. It begins at the inner side of the orbital 

 lobe and passes upward and backward to the junction of 

 the calloso-marginal and Rolandic fissures. Behind, it is 

 the quadrate convolution, which is separated from the 

 cuneate lobule by the parieto-occipital fissure. These 

 three convolutions the marginal, quadrate, and cune- 

 ate are all placed along the free border of the longi- 

 tudinal fissure. 



