藏绵羊脑动脉系统的结构特征

Structural features of cerebral arterial system in Tibetan sheep

以成年欧拉型藏绵羊头为试验材料,采用管道铸型腐蚀技术,制作了藏绵羊脑动脉系统的铸型标本,用大体解剖学方法对其结构特性开展了研究。结果显示,藏绵羊颅内主要脑动脉由脑部颈动脉、大脑动脉环和各脑动脉分支组成;大脑动脉环的整体形状呈＂倒葫芦＂形,管径均匀一致,其上发源的脑动脉各分支左右对称,基本走形相同;藏绵羊的脑硬膜外异网主要由一对左右对称的长三角形四面体构成,脑异网左右两叶间有2～3条＂V＂型吻合支呈疏松或紧密连接。藏绵羊大脑动脉环与其他动物类似,主要脑动脉间少有细小侧支出现。本试验观察的藏绵羊标本,其左、右大脑前动脉之间没有交通支连接;藏绵羊与牛科动物比较,其颅外主要的供脑血管网无脑硬膜外后异网及附属结构。

In present study,some head samples of Tibetan sheep were collected in Qinghai province,and vascular corrosion casts of the cerebral arterial system were made,then their structural features were observed and analyzed by gross anatomic method.The intracranial cerebral arteries of Tibetan sheep were mainly composed of cerebral carotid artery,cerebral arterial circle and cerebral arterial branches.The basic shape of cerebral arterial circle looks like＂reverse calabash＂,its vessel caliber were homogeneous,and main cerebral arteries branches from it were eudipleural and showed similar spread.The epidural retia mirabile of Tibetan sheep was composed of a pair of long eudipleural tetrahedron,and there were 2or 3＂V＂shape anastomotic vessels between both sides of the retia.Study results showed that composition of cerebral arterial circle of Tibetan sheep was similar to other domestic animals,and there were few thin branches from main intracranial arteries.There was no anterior communicating artery between both sides of anterior cerebral arteries in Tibetan sheep in present samples.The anatomical features of main extracranial arteries of supplying blood to the brain were not similar to bovine animals,such as no posterior retia and its attached structures.