SULCI ON THE MESIAL SURFACE. 



753 



one or two small gyri uniting the adjacent convolutions. Some 

 distance before its posterior termination it sends a small limb 

 upwards, which forms the anterior limit of a convolution (para- 

 central, fig. 273, or) enclosing the upper end of the Rolandic, or 

 central sulcus on its mesial aspect. 



The par id o- occipital or perpendicular fissure (fig. 273, po) is a Parieto- 

 deep cleft which descends from the upper margin of the hemisphere 

 at the back part, with a slight inclination forwards, to join the 



FIG. 273. SULCI AND CONVOLUTIONS OF THE INNKR ASPECT OF THE 

 HEMISPHERE. 



Fissures and Sulct : 



cia. Calloso-marginal. 

 po. Parieto-occipital fissure. 

 c. Calcarine fissure. 

 h. Hippocampal or dentate fissure. 

 coll. Collateral fissure (fourth tem- 

 poral hollow). 



it. Third temporal sulcus. 



Convolutions : 



M. Marginal. 



Ov. Para-central, or oval, lobule. 



Call. Callosal convolution. 



Q. Pnecuneus or quadrate lobule. 



Can. Cuneate lobule. 



u. Uncinate convolution (fifth 

 temporal). 



EOT. Fourth temporal (occipito- 

 temporal). 



IT. Third temporal. 



FD. Dentate convolution or fascia 

 dentata. 



TH. Taenia hippocampi. 



* Cut surface of optic thalamus. 



fissure. 



calcarine fissure on a level with the hinder end of the corpus 

 callosum. 



The calcarine fissure (c) is nearly horizontal. It begins close to Calcarine 

 the posterior extremity of the hemisphere, and is directed forwards, 

 receiving the parieto-occipital fissure about the middle of its length, 

 to end a little below the splenium of the corpus callosum. It gives 

 rise to the eminence called the hippocampus minor in the lateral 

 ventricle. The posterior and anterior parts of this fissure are 

 developed separately at first ; and if the student opens up the 

 fissure near the entrance of the parieto-occipital he will see a small 

 D.A. 3 c 



