Till-: < 'EREBRAL 



835 



The inferior temporal gyrus forms the infero-lateral border of the temporal lolie, 



and is usually more l>rnken up than the two gyri above it. It Ix'gins continuous \vith 

 them in the temporal pole, and extends hori/.ontally backwards into the lateral gyri of 

 the occipital lobe. It is separated from the middle gyrus by the middle temporal 

 sulcus, which likewise is never so com inuous a furrow as t he superior temporal sulcus. 

 I'Veijiiently it occurs in detached portions and often terminates within the temporal 



The fusiform gyrus is in the basal and tentorial surface of the lobe (fig. (i'Jl). 

 Its usual somewhat spindle shape surest* its name, and it is continuous backwards 

 into the occipital gyri. or its posterior end may be completely isolated by a union of 

 the itijiriiir trm /M>r<il sulciis and the collateral fissure, which two furrows separate 

 it from its neighbours OD either side. Anteriorly the fusiform gyrus runs into the com- 

 mon substance of the other three gyri at the temporal pole. 



The lingual gyrus is usually included in the tentorial .surface of the temporal lobe, 

 though in some texts it is regarded asa part of the occipital lobe. Its larger, posterior 

 portion is continuous with and lies within the boundaries of the occipital lobe. 



FIG. 622. OUTLINE DUAVVING OF CONVEX SURFACE OF LEFT CEREBRAL HEMISPHERE. 

 (After Tuldt, "Atlas of Human Anatomy," liulmuin, London and New York.) 



PRSCKXTKA1. Sl'LCi'S 



CKXTKAL SULCUS (KOLAKDl} 



aniiiim.vT.ii. 



KAMI'S (If IXTER. 

 PAK1KTM. 



Bounded laterally by the collateral fissure, it is continuous anteriorly into the hip- 

 p<>c;mip:d gyrus of the rhineiirephalon. 



All of the sulci give off occasional lateral twigs (Innisrcrse temporal sulci) which 

 themselves may or may not branch, and which tend to divide the main gyri into trans- 

 verse temporal gyri. 



The lateral fissure (fissure of Sylvius.). As promised in its origin by the over- 

 lapping and enclosing of the broad floor of the Sylvian fossa by the adjacent folds of 

 the pallium, the lateral fissure is t he deepest and most conspicuous fissure of the cere- 

 bral hemisphere. Its main divisions are a short stem and three branches. The 

 stem lies in the basal surface of the hemisphere, where it begins in a depression in the 

 anterior perforated substance, the nillicul-i Si/lrii, and passes forwards and upwards 

 between and separating the temporal pole and the superciliary border of the frontal 

 lobe. It corresponds in direction with the posterior border of the lesser wing of the 

 sphenoid bone, which projects backwards into it. and it contains the middle cerebral 

 artery, the Sylvian vein, and the sina- ala> parva-. It appears on the upper surface 

 at a point known in cranial topography as the Si/lria/i jim/it. where it divides into its 

 three branches: 



(1) The posterior ramus is the linear continuation of the fissure, and runs horizon- 



