AVNicking_ES - 1 ● Ikui noted that arteriole and venous...

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AV Nicking A vascular abnormality in the retina of the eye, visible on ophthalmologic examination, in which a vein is compressed by an arteriovenous crossing. The vein appears “nicked” as a result of constriction or spasm. It is a sign of hypertension, arteriosclerosis, or other vascular conditions. http://medical-dictionary.thefreedictionary.com/AV+nicking From emedicine: AV nicking (the Gunn sign): Impeded circulation results in a dilated or swollen vein peripheral to the crossing, causing hourglass constrictions on both sides of the crossing and aneurysmal-like swellings. Histologically, Spencer notes findings of various authors, to include the following:
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Unformatted text preview: 1 ● Ikui noted that arteriole and venous basement membranes are adherent with shared collagen fibers at the crossing points. Thickening of the basement membrane and the media of the arteriole in hypertension impinge on the vein and cause the crossing phenomenon. ● Mimatsu asserts that the crossing changes were due to sclerotic thickening of the wall of the venule and not by compression by the arteriole. ● Seitz attributed the crossing phenomenon to vascular sclerosis and perivascular glial cell proliferation and not to venous compression. http://emedicine.medscape.com/article/1201779-overview...
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This note was uploaded on 02/18/2012 for the course PAS 600 - 601 taught by Professor Garrubba during the Fall '10 term at Chatham University.

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