DISSECTING MANUAL. 



zontalis, prolonged by the ramus occipitalis. The intrapa- 

 rietal sulcus divides the surface into a superior and an in- 

 ferior parietal gyrus lying above and below it; and a posterior 

 central convolution lying in front of it, behind the fissure of 

 Rolando. The posterior Sylvian limb and the superior and 

 inferior temporal sulci divide the inferior parietal gyrus re- 

 spectively into the supra-marginal, angular, and postparietal 

 gyri. [563] 



Occipital Lobe. This is the pyramidal hinder part of the 

 hemisphere. The mesial surface is marked off by the internal 

 parieto-occipital fissure; this joins a fissure (calcarine) running 

 forward from the occipital pole to end just below the splenium; 

 the surface above the calcarine fissure is a triangular gyrus 

 (cuneus); that below it is the gyrus lingualis. The inferior 

 surface, which is marked off by an arbitrary line from the 

 pneoccipital notch to the isthmus of the limbic lobe, is the 

 posterior part of the occipito-temporal gyrus. The external 

 surface is marked off by the external parieto-occipital fissure 

 and its imaginary prolongation to the praeoccipital notch; 

 superiorly it presents the sulcus occipitalis transversus, a bifur- 

 cation of the ramus occipitalis; lower down a horizontal sulcus 

 (occipitalis lateralis) is seen. [564] 



Temporal Lobe. The external surface is bounded above by 

 the posterior Sylvian limb and its imaginary prolongation, 

 and behind by the imaginary prolongation of the external 

 parieto-occipital fissure; two horizontal sulci, the first and 

 second temporal, divide it into the superior, middle, and in- 

 ferior temporal gyri. The inferior surface is bounded in front 

 by the Sylvian stem, internally by the collateral fissure, and 

 posteriorly by the arbitrary line from the prseoccipital notch 

 to the isthmus of the limbic lobe. It consists of the front part 

 of the occipito-temporal gyrus and part of the inferior (third) 

 temporal gyrus; these are separated by the occipito-tem- 

 poral sulcus. It has also an upper opercular surface hidden in 

 the Sylvian fissure. [567] 



[40] 



