Jefferies P, Clemett R, Day T
Christchurch Hospital, New Zealand.
Aust N Z J Ophthalmol. 1993 Nov;21(4):213-7. doi: 10.1111/j.1442-9071.1993.tb00959.x.
To elucidate the anatomical features which predispose artery over vein (AV) crossings to be the preferential sites for retinal branch vein occlusions (RBVO), 11 AV and six vein over artery (VA) crossings in 12 eyes from non-hypertensive donors who were aged 35 to 82 years, were studied by light and electron microscopy. At AV crossings the veins were often observed to abruptly alter direction to pass under the artery. Here focal stratification of the vein basement membrane opposite the point of contact with the artery was seen. A focal reduction in the vein lumen occurred at three of 11 AV crossings. In contrast, deviation of the vein, focal basement membrane stratification or focal narrowing was not seen at VA crossings. Both types of crossings had a common adventitial sheath when each vessel was of large calibre. This study demonstrated anatomical features which predispose AV crossings to be the preferential site for venous occlusion.
为阐明使动脉跨静脉（AV）交叉处成为视网膜分支静脉阻塞（RBVO）优先发生部位的解剖学特征，我们对12只来自35至82岁非高血压供体的眼睛中的11个AV交叉处和6个静脉跨动脉（VA）交叉处进行了光镜和电镜研究。在AV交叉处，常观察到静脉突然改变方向从动脉下方穿过。在此，可见与动脉接触点相对的静脉基底膜出现局灶性分层。在11个AV交叉处中的3个出现了静脉管腔的局灶性缩小。相比之下，在VA交叉处未见静脉偏移、局灶性基底膜分层或局灶性狭窄。当每个血管管径较大时，两种类型的交叉处都有一个共同的外膜鞘。本研究证明了使AV交叉处成为静脉阻塞优先部位的解剖学特征。
