400 



Arteries of the Head. 



I' 



Lobus froiitalis 



A. cerebri media _ 



A. chorioidea 



Tractus opticus _ 

 Insula 



Corpus genl- 

 culatum laterale 



Corpus geni- 

 calatum mediale 



Pulvinar 



Pars centralis 

 ventriculi lateralis 



A. cerebri anterior 



A. coiiiniunicans anterior 



A. carotis interna 



A. communicans 

 posterior 



A. basilaris 

 A. cerebri posterior 



Corpora 

 quadrigemina 



Lobus occipitalis 



445. 

 A. cerebri media 



and 

 a. cinorioidea, 



on the right side, viewed iVom beh)w. 



(The teiii])oral lobe and the occipital lobe have been removed to open up the cornu inferius 



ventriculi lateralis and to permit the ibssa cerebri lateralis [Sylvii] to come into view; the 



cerebellum and the pons have been cut off just in front of their anterior margin.) 



3. A. conimiiiiicaiis posterior (posterior communicating arterv) (see also Figs. 444. 

 446 448) passes backward over tlie sinus euvernosus, below tlie tractus opticus and the pedun- 

 culus cerebri, lateralward fmiu the tuber cinereum and the corpus mamillare, gives off small 

 branches to the parts named and opens into the a. cerebri poslJerior (from the a. vertebralis). 



4. A. cerebri anterior (see also Figs. 444, 446448) runs medianward above the 

 n. opticus, sends branches to the cerebral ganglia through the substantia perforata anterior and 

 to the chiasma opticum. approaches closely the vessel of the same name of the other side and 

 forms a broad anastomosis with it by means of the a. communicans anterior. It next goes 

 into the fissura longitudinalis cerebri forming a loop u])ward around the anterior surface of 

 the genu corporis callnsi, lying directly upon it, and passes backward upon the corpus callosum. 

 It supplies the corpus callosum, the medial surface of the frontal and parietal lobes almost as 

 far as the fissura parietooccipitalis , the gyrus rectus , the lobus olfactorius , the gyri orbitales 

 as far as the medial limb of the sulci orbitales and the gyri frontales superior et medius. 



