| circulus zinnii | <anatomy, nerve> A network of branches of the short ciliary arteries on the sclera around the point of entrance of the optic nerve. Synonym: circulus vasculosus nervi optici, circulus arteriosus halleri, circulus zinnii, Haller's circle, Zinn's corona, Zinn's vascular circle. (05 Mar 2000) |
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| circulus | 1. Any ringlike structure. 2. A circle formed by connecting arteries, veins, or nerves. Origin: L. Dim. Of circus, circle (05 Mar 2000) |
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| circulus arteriosus cerebri | An anastomotic "circle" of arteries (roughly pentagonal in outline) at the base of the brain, formed, sequentially and in anterior to posterior direction, by the anterior communicating artery, the two anterior cerebral, the two internal carotid, the two posterior communicating, and the two posterior cerebral arteries. Synonym: circulus arteriosus cerebri, circle of Willis. (05 Mar 2000) |
| circulus arteriosus halleri | <anatomy, nerve> A network of branches of the short ciliary arteries on the sclera around the point of entrance of the optic nerve. Synonym: circulus vasculosus nervi optici, circulus arteriosus halleri, circulus zinnii, Haller's circle, Zinn's corona, Zinn's vascular circle. (05 Mar 2000) |
| circulus arteriosus iridis major | An arterial circle at the ciliary border of the iris. Synonym: circulus arteriosus iridis major. (05 Mar 2000) |
| circulus arteriosus iridis minor | An arterial circle near the pupillary margin of the iris. Synonym: circulus arteriosus iridis minor. (05 Mar 2000) |
| circulus articularis vasculosus | articular vascular circle, articular vascular network |
| circulus vasculosus nervi optici | <anatomy, nerve> A network of branches of the short ciliary arteries on the sclera around the point of entrance of the optic nerve. Synonym: circulus vasculosus nervi optici, circulus arteriosus halleri, circulus zinnii, Haller's circle, Zinn's corona, Zinn's vascular circle. (05 Mar 2000) |
| circulus venosus halleri | areolar venous plexus |
| circulus venosus ridleyi | Dural venous formation which surrounds the hypophysis, composed of right and left cavernous sinuses and the intercavernous sinuses. Synonym: circulus venosus ridleyi, Ridley's circle. A venous sinus at the periphery of the placenta. Synonym: sinus venosus sclerae. (05 Mar 2000) |