硬化大脑中动脉及豆纹支管壁弹性结构改变及意义

本文用光镜、电镜观察了正常和硬化大脑中动脉及其豆纹支管壁弹性结构的形态。结果显示，硬化大脑中动脉内弹力膜断裂，且以外层断裂明显，波纹状外观消失；而豆纹支内弹力膜结构完整，波纹状外观清晰可见。平滑肌萎缩、变性，胶原纤维增多。提示硬化大脑中动脉破裂出血是内弹力膜破坏，平滑肌萎缩，管壁脆性增加所致；而豆纹动脉是根部存在＂中膜缺损＂，此外受血流冲击引起破裂的可能性大。

Significance of changes in elastic structures of atherosclerotic middle cerebral artery and its lenticulostriate branch

The elastic structures of the middle cerebral artery (MCA) and its lenticulostriate branch in cadavers of healthy individuals and those of the patients with cerebral atherosclerosis were observed with light and electron microscopy. The results showed that the internal elastic lamina, especially its outer layer, broke into pieces and its wavy appearance disappeared in the atherosclerotic MCA, but the lamina nearly remained normal in appearance in the lenticulostriate branch in spite of the serious atherosclerosis of MCA. The smooth muscles in the media were atrophic and degenerated and there was proliferation of collagenous fibers in these atherosclerotic cerebral arteries. The findings suggest that the rupture in the atherosclerotic MCA be due to the damage of the internal elastic lamina , the atrophy of the smooth muscles in the media and the increase of fragility of the wall of the artery, while the rupture in the lenticulostriate branch be the result of the existence of "defects in its media" near the origin of the branch, as this part could possibly be broken by the momentum of the blood stream.