1 8 THE MENINGES OF THE BRAIN. 



the posterior cerebral which run forward in the transverse and 

 chorioidal fissures of the cerebrum to the chorioid plexuses of the 

 lateral and third ventricles (Fig. 7). 



The anterior chorioidal arteries (a. chorioidea anterior] rises 

 from the internal carotid artery just proximal to its anterior and 

 middle cerebral branches, and runs backward and outward along 

 the optic tract to the anterior inferior end of the chorioidal fissure, 

 which it enters (Fig. 10). It terminates in the chorioid plexus 

 of the inferior horn of the lateral ventricle, and gives collateral 

 branches to the optic tract, the gyrus hippocampi, the fascia 

 dentata, the hippocampus, the crus of the fornix and the posterior 

 part of the internal capsule. 



A2. The Ganglionic System of Arteries. Small arteries 

 from the arterial circle and from the cerebral arteries near the 

 circle constitute this system (Fig. 10). The arteries pass to 

 their distribution without communicating with one another or 

 with the cortical arteries. They are the end-arteries of Cohnheim. 

 Between the cortical and ganglionic systems, there is an area 

 poorly supplied with blood. That is the area of cerebral softening 

 in old age. The ganglionic system of arteries is made up of six 

 groups of small vessels: The antero-median, the right and left 

 antero-lateral, the postero-median and the right and left postero- 

 lateral. 



The antero-median ganglionic arteries rise from the anterior 

 cerebrals in front of the optic chiasma (Fig. 10). They supply 

 the chiasma, the lamina terminalis, the rostrum of the corpus 

 callosum, the septum pellucidum and the head of the caudate 

 nucleus. 



The antero-lateral ganglionic arteries take their origin, on 

 either side, from the middle cerebral artery, a little outside the 

 arterial circle (Fig. 10). They pierce the anterior perforated 

 substance and are distributed to the striated body, internal capsule 

 and thalamus. The largest one of this group is the lenticulo- 

 striate artery. It supplies the greater part of the corpus striatum. 

 On account of its frequent rupture, it is called the artery of cerebral 

 hemorrhage (Charcot). 



Postero-median Ganglionic Arteries. These are branches 



