AMERIOR CEREBRAL— MIDDLE CEREBRAL 50c 



(8) THE ANTERIOR CEREBRAL ARTERY 



The anterior cerebral artery (fig. 340) — one of the terminal branches into 

 which the internal carotid divides in the fissure of Sylvius — passes at first forwards 

 and inwards across the anterior perforated space bet^veen the olfactory and optic 

 nerves to the longitudinal fissure where it approaches its fellow of the o])i)Osite side, 

 and communicates with it by a short transverse trimk, about two lines long, known 

 as the anterior communicating artery. Onwards from this spot it runs side l)y 

 side Avith its fellow in the longitudinal fissure round the genu of the corpus 

 callosum; then, turning backwards, it continues along the upper surface of that 

 commissure, and, after giving off large branches to the frontal and parietal lobules, 

 anastomoses with the posterior cerebral artery. 



The branches of the anterior cerebral are: — (a) Communicating; (6) gan- 

 glionic, or central; (c) commissural; (f/) hemispheral, or cortical. 



(rt) Communicating. — The anterior communicating is a transverse trunk 

 about two lines in length, connecting the right and left anterior cerebral arteries. 

 It lies immediately in front of the oi)tic commissure across the lamina cinerea. It 

 gives off some of the antero-median branches which pass from the anterior 

 cerebral to the fore end of the caudate nucleus. Sometimes the anterior cerebral 

 arteries, instead of communicating by a transverse trunk, coalesce for a short 

 distance and then again diyide. Upon this short trunk the terminal filaments of 

 the carotid plexus of the sympathetic of either side meet in a small gangliform 

 enlargement known as the ' ganglion of Ribes. ' 



(h) Ganglionic, or central. — The antero-median group, together with the 

 antero-median branches of the anterior communicating, pass through the lamina 

 cinerea and supply the fore end of the caudate nucleus. 



(c) Commissural. — These supply the corpus callosum. 



((/) The hemispheral or cortical branches. — (i ) The orbital, three or four 

 in numl)t'r, supply the inferior surface of the first frontal convolution, and give off 

 small twigs to the olfactory bulb, (ii) The margino-frontal arise from the artery 

 as it lies on the corpus callosum, and, after supplying the marginal convolution, 

 pass on to the convex surface of the hemisphere and further supply the first and 

 second frontal convolutions and the upper part of the ascending frontal convolution, 

 (iii) The calloso-marginal supplies the callosal convolution and the upper part 

 of the marginal convolution, (iv) The quadrate is a 1)ranch to the convolution of 

 that name. 



(9) THE MIDDLE CEREBRAL ARTERY 



The middle cerebral artery (fig. 340) — the larger of the two terminal divisions 

 of the internal carotid — passes obliquely upwards and outwards into the fissure of 

 Sylvius, and opposite the insula or island of Reil divides into its hemispheral or 

 cortical branches. 



The branches of the middle cerebral are: — (a) Ganglionic, or central; and 

 (Jj) hemispheral, or cortical. 



(a) Ganglionic, or central. — (i) The caudate are two or three small 

 branches, which arise from the inner aspect of the artery and pass through the 

 inner part of the lloor of the fissure of Sylvius to the head of the caudate nucleus, 

 (ii) The antero-lateral are numerous small arteries, which pass througli tlie 

 anterior perforated space and supply the caudate nucleus (except its hea<l ). the 

 internal capsule, and part of the optic thalamus, (iii) The lenticulo-striate, 

 a larger branch of the antero-lateral set, passes through a separate hole in tlie 

 outer part of the anterior perforated space, runs upwards between the lenticular 

 nucleus (which it supplies) and the external capsule, perforates the internal 

 capsule, and terminates in the caudate nucleus. It has been so frequently found 

 ruptured in apoplexy, that it is called by Charcot the 'artery of cerebral ha'inor- 

 rhage. ' (iv) Sometimes a more or less distinct branch, called lenticulo-optic, is 

 distributed to the outer and hinder portion of the lenticular inicleus and the 

 external portion of the thalamus opticus. 



