中国人大脑动脉环(Willis氏环)的结构

THE PATTERN OF WILLIS’ CIRCLE IN CHINESE BRAIN

大脑动脉环位于蛛纲膜下腔内大脑脚间池中,蝶鞍上方,绕视交叉、灰结节和乳头体周围而排列。由环的前方、外侧和后方各发出大脑前动脉、大脑中动脉和大脑后动脉;同时,在构成环的各段动脉上发出许多细小的中央动脉,由脑底穿入脑实质中而分布于尾状核、豆状核、内囊、丘脑等。因此可以说整个大脑都是大脑动脉环的流域。

Willis’Circle of 162 Chinese brains was studied and the diameters of thecomponent arteries of this circle were measured in 51 brains for the purpose ofobtaining a pattern of this circle in Chinese and,in certain types,the possibleresult after the ligation of one side of the internal carotid artery.For comparison,12 dogs’brains were also studied.It was found that this circle may be divided into a fore part and a hind part,each of which may be again divided into a trunk trpe,a diffuse type and anintermediate type.In the fore part,the trunk type consists of 67.9%,the diffuse type 22.21%;the intermediate type 9.88%In the hind part,the followingtypes were observed:first subtype of the trunk type 83.3%;second subtype ofthe trunk type 6.17%;diffuse type 6.79%;intermediate type 1.735 and open type2.47%.The posterior communicating artery was found to be poorly developedor absent in 51.26%.In the dogs’brains there are two circles,one in front ofthe other.The front one is polygonal and the other one is rhomboid in shape,with a constant posterior communicating artery so that the circulation is morestablized as compared with that of the human brains.