| Haller's vascular tissue | <anatomy> The outer portion of the choroid of the eye containing the largest blood vessels. Synonym: lamina vasculosa choroideae, Haller's vascular tissue, uvaeformis, vascular layer of choroid coat of eye, vascular layer. (05 Mar 2000) |
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| arterial circle of cerebrum | 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) |
| articular vascular circle | An anastomosis of vessels encircling a joint. See: articular vascular network. Synonym: circulus articularis vasculosus. (05 Mar 2000) |
| Baudelocque's uterine circle | A constriction located at the junction of the thinned lower uterine segment with the thick retracted upper uterine segment, resulting from obstructed labour; this is one of the classic signs of threatened rupture of the uterus. Synonym: Bandl's ring, Baudelocque's uterine circle, Scanzoni's second os. (05 Mar 2000) |
| Pagenstecher's circle | In the case of a freely movable abdominal tumour, the mass is moved throughout its entire range, its position at intervals being marked on the abdominal wall; when these points are joined, a circle is formed, the centre of which marks the point of attachment of the tumour. (05 Mar 2000) |
| vascular circle | The circle around the mouth formed by the inferior and superior labial arteries. Synonym: areolar venous plexus. (05 Mar 2000) |
| vascular circle of optic nerve | <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) |
| Ramsden circle | <microscopy> The circular spot of light formed at that distance above the eyepiece where the chief image forming rays cross, the back focal plane of the eyepiece. The objective back focal plane is in conjugate focus in this same plane. In visual microscopy, the point where the pupil of the eye is placed. (05 Aug 1998) |
| venous circle of mammary gland | areolar venous plexus |
| Carus' circle | An imaginary curved line obtained from a mathematical formula, supposed to indicate the outlet of the pelvic canal. Synonym: Carus' circle. (05 Mar 2000) |
| vicious circle | The mutually accelerating action of two independent diseases or phenomena, or of a primary and secondary affection, the passage of food, after a gastroenterostomy, from the artificial opening through the intestinal loop by antiperistaltic action and back into the stomach again by the pyloric orifice, or the reverse. (05 Mar 2000) |
| cerebral arterial circle | The roughly pentagonally shaped circle of vessels on the ventral aspect of the brain in the area of the optic chiasm, hypothalamus, and interpeduncular fossa. See: circle of Willis. (05 Mar 2000) |
| greater arterial circle of iris | An arterial circle at the ciliary border of the iris. Synonym: circulus arteriosus iridis major. (05 Mar 2000) |
| Ridley's circle | 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) |
| rolling circle | A mechanism for the replication of circular DNA. (05 Mar 2000) |