THE CEREBRAL CIRCULATION, ARTERIES. 1 7 



the posterior fourth of the middle frontal gyrus. (3) The ascend- 

 ing parietal, whose course is along the interparietal sulcus, fur- 

 nishes blood to the posterior central gyrus and the adjacent 

 parts of the superior and inferior parietal lobules. (4) The 

 par ieto- temporal arteries, which comprise two polar branches 

 to the temporal lobe and a large posterior branch. The latter 

 runs in the posterior ramus of the lateral cerebral fissure to its 

 upturned posterior end and there bifurcates into a parietal and a 

 temporal branch, which just pass the anterior limit of the occip- 

 ital lobe. The entire distribution of the parieto-temporal arteries 

 is to the temporal pole and to the superior, middle and part of 

 the inferior temporal gyri; to the major parts of the supramar- 

 ginal, angular and post-parietal gyri, and to a very small portion 

 of the superior and lateral occipital gyri. 



The posterior cerebral artery (a. cerebri posterior}, a ter- 

 minal branch of the basilar, lies in the posterior boundary of the 

 arterial circle and is joined to the internal carotid by the posterior 

 communicating artery (Figs. 10 and 12). It winds backward 

 between the midb^ain and gyrus hippocampi to the tentorial 

 surface of the cerebral hemisphere where, just beyond the splenium 

 of the corpus callosum, it terminates in the calcarine and occipito- 

 parietal branches. From the posterior cerebral arteries originate 

 the postero-median and the postero-lateral ganglionic, and two 

 or more posterior chorioidal arteries and three cortical 

 branches: (i) The temporal branches, often an anterior, middle 

 and posterior temporal, which supply the hippocampal and the 

 fusiform gyri and a part of the lingual and of the inferior tem- 

 poral gyrus. 



(2) The calcarine artery, which runs along the fissure of the 

 same name and supplies the cuneate and lingual gyri; also the 

 pole and the lateral and superior gyri of the occipital lobe. (3) 

 The occipito- parietal artery, a single branch, which runs along 

 the sulcus occipito-parietalis over the supero-medial border to 

 the convex surface of the cerebral hemisphere and is distributed 

 to the cuneus, the praecuneus and the superior occipital gyrus. 



The posterior chorioidal arteries (arteries chorioidea poste- 

 rior es, Figs. 7, 9 and 10) two or more in number are branches of 



