OBSERVATION ON VASCULAR CASTS OF UVEA NEWBORNS BY SCANNING ELECTRON MICROSCOPY / 解剖学报

ABSTRACT

Ten fresh eye balls removed from five newborn cadavers were studied.About2-4 hrs after death,cadavers were injected through both common carotid arteries withABS at a constant pressure between 120～150 mmHg.ABS-injected eyes were enucleatedand were cut into halves through equator or meridian.The specimens were digestedin 40% KOH.The corrosion-cast models of blood vessels in uvea were observed underthe SEM.The chief results of observation were as followsWithin the choroid,the blood vessels lie in stratified layers.The large vesselsare located in the outermost layer,next to this layer are smaller vessels.The innermostlayer consists of a continuous single layer of capillaries.The choriocapillaries end around the optic disc.This finding indicates that thechoriocapillaries are not directly involved in the disc circulation.Each short posterior ciliary artery supplied a segment of the choriocapillaries,with some capillary anastomosis between segments,so that the choriocapillaries werearranged in one plane as a single continuous layer of capillaries forming a network.The network of the choriocapillaries consisted of lobules of choriocapillaries.The precapillary arteriole lie in its center.In each lobule meshed capillaries appearedto radiate from a central focus.The postcapillary venule lay on the periphery of thelobule.The lobules varied in their geometric configuration,forming irregularlytriangular to hexagonal shapes.The average size of a lobules of newborn's chorioca-pillaries was 230/420? to 460/520?.The diameter of the choriocapillary varies between8? and 20?.The blood vessels of the ciliary body and iris divide from large circular arteryof iris and long posterior ciliary arteries.Each ciliary process contained a small arterywhich randomly branched to form a capillary network.It is drained by venule.