Blackburn, Anomalies of Encephalic Arteries. 507 



Case 2092. H. F.; colored; female; aged 65; senile dementia. Slight arterio-sclerosis. Both pos- 

 terior communicating arteries very large and supply the posterior cerebral region, the posterior cerebral 

 of the right side being represented by a small thread which was impervious, and the left is a small trunk 

 which curves around the crus but does not join the posterior communicating artery. 



Case 2094. S. S. T.; white; male; aged 65; chronic mania. Arterio-sclerosis. The vertebral 

 arteries are connected by a transverse trunk of considerable size, from which arises the anterior spinal 

 artery. Right anterior inferior cerebellar artery absent, and branches from the posterior inferior 

 cerebellar take its place. 



Case 2097. P. McC; white; male; aged 74; chronic dementia. Arterio-sclerosis. Posterior com- 

 municating artery of left side very large; the posterior cerebral very small; posterior communicating 

 artery of opposite side very small, posterior cerebral very large. Anterior communicating artery double. 

 Right posterior inferior cerebellar artery large; anterior inferior cerebellar small. 



Case 2099. M. D.; white; female; aged 71; senile dementia. Arterio-sclerosis. Right anterior 

 cerebral artery very small; the left is very large, divides into two trunks which correspond to the two 

 anterior cerebral arteries, and there appears to be no true anterior communicating artery. The right 

 posterior cerebral artery apparently arises from the carotid, and is only united to the basilar by a very 

 small branch of a rudimentary vessel which is mainly distributed to the crus and interpeduncular space. 



Case 2137. C. N.; white; male; aged 66; senile dementia. Arterio-sclerosis. Right anterior 

 cerebral artery very small, its place being taken by the opposite artery which supplies the two vessels 

 through an enlarged anterior communicating artery. Right posterior communicating artery large, 

 posterior cerebral small. Left posterior inferior cerebellar artery absent, its place being taken by a 

 large branch from the anterior inferior cerebellar artery. 



Case 2139. R. W. E.; white; male; aged 48; chronic epileptic dementia. Arterio-sclerosis. The 

 two anterior cerebral arteries join into a common trunk just anterior to the anterior communicating 

 artery leaving a triangular opening between the vessels. The two arteries then form a large vessel about 

 one-half an inch in length after which they again divide and the upper vessel forms a callosal artery, 

 while the other branch is mainly distributed to the medial surface anteriorly. On the left side, opposite 

 the junction of the anterior communicating artery with the anterior cerebral a three branched trunk 

 arises, the anterior branch taking the place of the anterior cerebral artery of this side, the middle branch 

 distributed to the orbital surface, and the posterior branch goes backward to supply Broca's convolution 

 and the insula. The right posterior inferior cerebellar artery is absent, the anterior inferior being 

 rather large. (Fig. 5.) No. 2139; all of the branches not represented. 



Case 2141. J. C; white; male; aged 80; senile dementia. Arterio-sclerosis. The two anterior 

 cerebral arteries join directly into a single trunk without an anterior communicating artery. This 

 trunk extends to the genu callosi where it again divides into two vessels which are distributed normally. 

 A large branch which arises from the junction of the vessels supplies the orbital and medial regions of 

 the left frontal lobe and is possibly the representative of the left anterior cerebral artery. The right 

 posterior communicating artery is very large, corresponding posterior cerebral artery very small at its 

 origin from the basilar. Left superior cerebellar artery is doubled. (Fig. 5.) 



Case 2153. R. W.; white; female; aged 66; senile dementia. Arterio-sclerosis. Anterior commu- 

 nicating artery very small and imper\-ious. Left anterior cerebral does not lie close to the genu of the 

 callosum but is distributed to the orbital, and outer anterior medial surfaces of the left side; the opposite 

 artery furnishes a single callosal artery, only one being present. Both posterior communicating arteries 

 are large and supply the territory of the posterior cerebral arteries, these vessels being small at their 

 origin. (Fig. 5.) 



Case 2159. P. J.; white; male; aged 66; senile dementia. No disease of arteries. Right posterioi 

 communicating artery large; posterior cerebral artery of this side practically absent being joined to the 

 former artery by a small impervious branch. Posterior communicating artery of left side enlarged and 

 the posterior cerebral very small. The basilar, both vertebrals, and the posterior inferior cerebellar 

 arteries are quite small. Anterior communicating artery absent. (Fig. 6.) 



Case 2160. J. S. G.; white; male; aged 66; chronic mania. Slight arterio-sclerosis. Left vertebral 

 as large as the basilar; right small and the posterior inferior cerebellar artery receives nearly all the blood 

 brought by the lower part of the vertebral artery. Left posterior communicating artery unusually 

 large. Small aneurism at origin of right anterior choroid artery. 



Case 2163. A. H. T.; white; male; aged 68; senile dementia. Arterio-sclerosis. Posterior com- 

 municating artery of left side represented by an extremely small vessel. The left anterior choroid artery 

 is unusually large; it lies at its first part deeply in the hippocampal fissure and branches supply the 

 ■choroid plexus; it finally emerges and forms the parieto-occipital and the calcarine artery. The posterior 

 cerebral of this side is distributed mainly to the inferior temporal region and the crus. On the right 



