446 



THE BRAIN 



Arteria Cerebri Posterior. Immediately beyond the origin 

 of the two superior cerebellar arteries the basilar trunk 

 bifurcates into the two posterior cerebral arteries. These 

 diverge from each other, and, curving laterally and posteriorly, 

 encircle the mesencephalon. Then they run posteriorly towards 

 the under surface of the splenium of the corpus callosum. 

 In this course each posterior cerebral artery lies deeply in 

 the interval between the corresponding pedunculus cerebri 

 and the hippocampal gyrus, and, finally, passing on to the 

 tentorial surface of the cerebral hemisphere it disappears 



Intermediate medial frontal 



Posterior medial frontal 



Anterior medial frontal 



Parieto- 



occipital 



branch 



Medial orbital 

 branches 

 Anterior cerebral artery 



Calcarine branch \1/ Posterior cerebral artery 



Temporal branches 



FIG. 178. Medial and Tentorial Surfaces of the left Cerebral Hemisphere. 

 The district supplied by the anterior cerebral artery is tinted purple ; by 

 the middle cerebral artery, blue ; and by the posterior cerebral artery, 

 red. (Semi-diagrammatic. ) 



from view, by sinking into the anterior extremity of the cal- 

 carine fissure. In this fissure the artery ends by dividing into 

 two terminal branches, viz., the calcarine and the parieto- 

 occipital (Figs. 178 and 180). 



The oculo-motor nerve passes anteriorly in the interval 

 between the posterior cerebral and the superior cerebellar 

 arteries, close to the place where they arise from the basilar ; 

 and the small trochlear nerve winds round the pedunculus 

 cerebri below the posterior cerebral artery. 



The following branches spring from the posterior cerebral artery : 



f Postero-median. ( Temporal. 



Central or basal \ Postero-lateral. Cortical -j Calcarine. 



[ Posterior chorioidal. [ Parieto-occipital. 



