206 



HUMAN PHYSIOLOGY. 



1. The paracentral lobule, lying in the region of the upper extremity 

 of the fissure of Rolando ; it contains the large giant cells of Betz. 

 Injury to this convolution is followed by degeneration of the 

 motor tract. 



2. The gyrus fornicatus, lying below the callosomarginal fissure. 

 Running parallel with the corpus callosum, it terminates at its 

 posterior border in the hippocampal gyrus. 



FIG. 25. DIAGRAM SHOWING FISSURES AND CONVOLUTIONS ON MESIAL ASPECT 

 OF THE RIGHT HEMISPHERE. 



Median aspect of the right hemisphere. CC. Corpus callosum divided longi- 

 tudinally. Gf. Gyrus fornicatus. H. Gyrus hippocampi, h. Sulcus hippo- 

 campi. U. Uncinate gyrus. cm. Callosomarginal fissure. FI. First 

 frontal convolution, c. Terminal portion of fissure of Rolando. A. As- 

 cending frontal, B. Ascending parietal, convolution and paracentral lobule. 

 PI'. Praecuneus or quadrate lobule. Oz. Cuneus. Po. Parieto-occipital 

 fissure, o. Transverse occipital fissure, oc. Calcarine fissure. oc f . Su- 

 perior, oc". Inferior, rami of the same. D. Gyrus descendens. T*. 

 Gyrus occipitotemppralis lateralis (lobulus fusiformis). T 5 . Gyrus occipi- 

 totemporalis medialis (lobulus lingualis). 



3. The gyrus hippocampus (H) is formed by the union of the pre- 

 ceding convolution with the occipitotemporal. It runs forward and 

 terminates in a hooked extremity uncus. 



4. The quadrate lobule, or pracuneus, lies between the upper ex- 

 tremity of the callosomarginal fissure and the parieto-occipital. 



