| casting ring | A metal tube in which a refractory mold is made for casting metal dental restorations or appliances. Synonym: casting flask, casting ring. (05 Mar 2000) |
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| Vieussens' ring | A muscular ring surrounding the fossa ovalis in the wall of the right atrium of the heart. Synonym: annulus ovalis, margin of fossa ovalis, Vieussens' annulus, Vieussens' isthmus, Vieussens' limbus, Vieussens' ring. (05 Mar 2000) |
| glaucomatous ring | A yellowish white ring surrounding the optic disk, indicating atrophy of the choroid in glaucoma. Synonym: glaucomatous ring. A halo surrounding lights, caused by corneal oedema in glaucoma. Synonym: rainbow symptom. (05 Mar 2000) |
| pathologic retraction ring | 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) |
| medial crus of the superficial inguinal ring | Portion of the external oblique aponeurosis which passes medial to the superficial inguinal ring forming the medial boundary of the ring. Synonym: crus mediale annuli inguinalis superficialis. (05 Mar 2000) |
| Vossius' lenticular ring | A ring-shaped opacity found on the anterior lens capsule after contusion of the eye, due to pigment and blood. (05 Mar 2000) |
| Graefenberg ring | An obsolete term for a silver or silkworm gut ring designed for insertion into the uterine cavity as a means of contraception. (05 Mar 2000) |
| greater ring of iris | The outer, broader of the two zones of the iris. Synonym: annulus iridis major. (05 Mar 2000) |
| ring | A circle, or a circular line, or anything in the form of a circular line or hoop. 2. Specifically, a circular ornament of gold or other precious material worn on the finger, or attached to the ear, the nose, or some other part of the person; as, a wedding ring. "Upon his thumb he had of gold a ring." (Chaucer) "The dearest ring in Venice will I give you." (Shak) 3. A circular area in which races are or run or other sports are performed; an arena. "Place me. O, place me in the dusty ring, Where youthful charioteers contened for glory." (E. Smith) 4. An inclosed space in which pugilists fight; hence, figuratively, prize fighting. "The road was an institution, the ring was an institution." 5. A circular group of persons. "And hears the Muses in a Aye round about Jove's alter sing." (Milton) 6. <geometry> The plane figure included between the circumferences of two concentric circles. The solid generated by the revolution of a circle, or other figure, about an exterior straight line (as an axis) lying in the same plane as the circle or other figure. 7. <astronomy> An instrument, formerly used for taking the sun's altitude, consisting of a brass ring suspended by a swivel, with a hole at one side through which a solar ray entering indicated the altitude on the graduated inner surface opposite. 8. <botany> An elastic band partly or wholly encircling the spore cases of ferns. 9. A clique; an exclusive combination of persons for a selfish purpose, as to control the market, distribute offices, obtain contracts, etc. "The ruling ring at Constantinople." (E. A. Freeman) Ring armor, armor composed of rings of metal. See Ring mail, below, and Chain mail, under Chain. <chemistry> Ring blackbird, a graphic formula in the shape of a closed ring, as in the case of benzene, pyridine, etc. Ring mail, a kind of mail made of small steel rings sewed upon a garment of leather or of cloth. Ring micrometer. <astronomy> The ring ousel. The prize ring, the ring in which prize fighters contend; prize fighters, collectively. The ring. The body of sporting men who bet on horse races. The prize ring. Origin: AS. Hring, hrinc; akin to Fries. Hring, D. & G. Ring, OHG. Ring, hring, Icel. Hringr, DAn. & SW. Ring; cf. Russ. Krug'. Cf. Harangue, Rank a row,Rink. 1. To surround with a ring, or as with a ring; to encircle. "Ring these fingers." 2. <botany> To make a ring around by cutting away the bark; to girdle; as, to ring branches or roots. 3. To fit with a ring or with rings, as the fingers, or a swine's snout. Origin: Ringed; Ringing. <veterinary> To rise in the air spirally. Source: Websters Dictionary (01 Mar 1998) |
| ring abscess | An acute purulent inflammation of the corneal periphery in which a necrotic area is surrounded by an annular girdle of leukocytic infiltration. (05 Mar 2000) |
| ring chromosome | A structurally abnormal chromosome in which the end of each chromosome arm has been lost and the broken arms have been reunited in ring formation. A ring chromosome is denoted by the symbol r. (12 Dec 1998) |
| ring chromosomes | Aberrant chromosomes with no ends. (12 Dec 1998) |
| ring compound | Any compound in which the constituent atoms, or any part of them, form a ring. Used mainly in organic chemistry where: 1) numerous compound's contain rings of carbon atoms (carbocyclic compound's) or carbon atoms plus one or more atoms of other types (heterocyclic compound's), usually nitrogen, oxygen, or sulfur; 2) where the atoms in the ring are all of the same element (homocyclic or isocyclic compound); 3) where the ring is saturated or contains nonconjugated double bonds (alicyclic compound), the compound is similar in properties to the corresponding acyclic compound (e.g., cyclohexane resembles hexane); 4) where the ring contains conjugated double bonds in a closed loop in which there are 4n + 2 (where n is an integer) delocalised π electrons (Huckel's rule) (aromatic compound; e.g., benzene, pyridine), it is more stable than the corresponding saturated ring and exhibits unusual chemical properties characteristic of itself and not of other types of rings or of acyclic compound's. These aromatic compounds have the ability to sustain an induced ring current. Synonym: closed chain compound, ring compound. (05 Mar 2000) |
| ring enhancement | In computed tomography, when a bright circle appears on an image made after injection of contrast medium, characteristic of localization of the contrast in the wall of an abscess. (05 Mar 2000) |
| ring finger | Fourth finger. Synonym: digitus annularis, fourth finger. (05 Mar 2000) |