404 



THE BRAIN 



and a half to tivo inches] anterior to the occipital pole. It is 

 about 12.5 mm. (half an inch} in length, and it is brought 

 to an abrupt termination laterally by an arching gyms, called 

 the arcus parieto-occipitalis, which winds round it (Fig. 154). 



The medial part of the parieto-occipital fissure (Fig. 159) 

 will be seen when the medial surface of the hemisphere is 

 studied (p. 419). 



The Lobes seen on the Supero-lateral Surface of the 



Central sulcus Anterior central gyrus 

 Posterior central gyrus ^ j Central sulcus 

 Superior parietal lobule \ _^ j Superior post-central sulcus 



Arcus parieto- 

 occipitalis, at lateral 



end of parieto- 

 occipital fissure \ 



Angular gyrus 

 Superior 

 temporal 

 sulcus 



Post-parietal, 

 gyrus 



Middle 



temporal 



gyrus 



Middle 



temporal 



sulcus 



Inferior 



temporal 



gyrus 



Lateral .- 



occipital 



sulcus 



Sulcus lunatus 



Inferior post-central 

 ulcus 



Interparietal sulcus 

 - (proprius) 



Par-occipital 

 -. sulcus 



Superior 



temporal sulcm 



Transverse 

 "occipital sulcus 



Middle 



temporal sulcus 

 .Paramedial 



occipital sulcns 

 . Lateral 



occipital sulcus 



-./.Sulcus lunatus 



Calcarine fissure 



alcarine fissure 

 Sulcus for superior sagittal sinus 



FIG. 154. Posterior view of the Hemispheres of the Brain (semi-diagram- 

 matic). The posterior parts of the supero-medial borders are separated 

 and portions of the medial surfaces are seen (shaded). 



Hemisphere, and the Insula. The dissector must understand 

 that the areas called the lobes of the cerebrum are defined 

 merely for purposes of description and localisation ; they 

 do not correspond with physiological areas, nor do they 

 correspond, exactly, in extent with the bones after which 

 they are named. For example, the lobes which can be seen 

 on the supero-lateral surface, without any disturbance of its 

 parts, are the frontal, the parietal, the occipital and the 

 temporal. It is true that all those lobes lie in relation with 

 the bones after which they are named, but only the parietal 



