视交叉侧动脉显微解剖特点与垂体瘤患者视功能障碍的关系

Microanatomy of lateral chiasmal arteries and visual disturbance caused by pituitary adenomas

目的通过对视交叉侧动脉特点的显微解剖学研究,探讨其在垂体瘤致视功能障碍中的意义。方法10例福尔马林固定的国人成人头颅标本,经双侧颈内动脉和椎动脉灌注红色乳胶后取脑,手术显微镜下剥离鞍区蛛网膜,暴露颈内动脉颅内段、Willis环及其穿动脉,以及垂体柄、视交叉、大脑脚、乳头体等鞍区重要结构。观察视交叉侧动脉的起始、走行、分支和分布,测量其起始部的直径并显微摄影。结果视交叉侧动脉自颈内动脉C2段内侧壁发出,在蛛网膜下腔迂曲走行,起始部位靠上,几乎与视交叉处于同一水平,直径（0.18±0.06）mm,在到达视交叉之前发出2～3条亚支,呈＂分水岭＂样分布于视交叉侧缘、视交叉侧部的上面和下面（以下面为主）靠外侧的部分以及视神经近视交叉处外侧半。视交叉侧动脉具有较长的脑外游离段,各穿动脉主干之间不吻合,而在软膜上与邻近穿动脉之间存在广泛的终末吻合。结论垂体瘤不易累及视交叉侧动脉可能是垂体瘤患者鼻上象限视野往往可以长时间保留的原因。

Objective To illustrate the significance of lateral chiasmal arteries （LCAs） in visual disturbance caused by pituitary adenomas（PAs）,the microanatomical characteristics of LCAs were studied. Methods LCAs of 10 adult brain specimens,which were fixed with formalin and injected with colored mass,were observed and taken measure using microanatomical technique. Results LCAs arised from the medial wall of supraclinoid segment （C2 segment） of internal carotid artery （ICA）. Each vessel ramified several twigs （from 2 to 3） into the lateral margin,superior and inferior aspects of the lateral part of the optic chiasma（OC）,and the lateral half of the optic nerve（ON） neighboring the OC. In summary,the perforating arteries with long free segments of the external brain took the form of chains or series of irregular loops,ran in the subarachnoid space and feed special areas. Their major trunks were not communicated each other during the course. But there were rich terminal anastomoses on the pial mater of the brain. Conclusion LCAs are not apt to being invaded by PAs,which might be the cause that the of superonasal quadrant visual field could preserve for long time in patients with PAs.