. Anatomy, descriptive and applied. Anatomy. 618 THE VASCULAR SYSTEMS is maintained in little more than half the recorded cases. In the other cases there are different variations. The three trunks which together supply each cerebral hemisphere arise from the circle of Willis. From its anterior part proceed the two anterior cerebrals, from its antero-lateral part the middle cerebrals, and from its posterior part the posterior cerebrals. Each of these principal arteries gives origin to two ^'e^y dif- ferent systems of secondary vessels. One of these systems has been named the central ganglionic
. Anatomy, descriptive and applied. Anatomy. 618 THE VASCULAR SYSTEMS is maintained in little more than half the recorded cases. In the other cases there are different variations. The three trunks which together supply each cerebral hemisphere arise from the circle of Willis. From its anterior part proceed the two anterior cerebrals, from its antero-lateral part the middle cerebrals, and from its posterior part the posterior cerebrals. Each of these principal arteries gives origin to two ^'e^y dif- ferent systems of secondary vessels. One of these systems has been named the central ganglionic system, and the vessels belonging to it supply the central ganglia of the brain; the other has been named the cortical arterial system, and its vessels ramify in the pia and supply the cortex and subjacent medullary substance. These two systems, although they have a common origin, do not communicate at any point of their peripheral distribution, and are entirely independent of each other, representing terminal arteries. Though some of the arteries of the cortical system approach, at their terminations, the regions supplied by the central ganglionic system, no communication between the two sets of vessels takes place, and there is between the parts supplied by the two systems a borderland of diminished nutritive activity. In the brains of old people softening is especially apt to occur in this ill-nourished territory. Anterior cerebral- Middle cerebral Anterior choroit Posterior communicating- Posterior cerebral- Anterior cojnmunicating Superior cerebellar- Basilar Anterior inferior cerebellar- Interior auditory Posterior inferior cerebellar Vertebral. E. A. S. Posterior spinal' "Anterior spinal Fig. 453.—Diagram of the arteries at the base of the brain, including the circle of Willis. I. Antero-median group of ganglionic branches. II. Poatero-median group. III. Right and left antero-lateral group. IV. Right and left postero-Iateral group. The Central Ganglionic System.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1913
