1. [TA] In anatomy, a ring-shaped structure or group of structures, as formed by anastomosing arteries or veins, or by connected (communicating) nerves, 2. A line or process with every point approximately equidistant from the center. SYN: circulus [TA]. [L. circulus]
- articular vascular c. SYN: articular vascular plexus. See articular vascular network.
- Carus c. SYN: Carus curve.
- cerebral arterial c. [TA] the roughly pentagonally shaped c. of vessels on the ventral aspect of the brain in the area of the optic chiasm, hypothalamus, and interpeduncular fossa; 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. SYN: circulus arteriosus cerebri [TA], arterial c. of cerebrum, c. of Willis.
- closed c. a circuit for administration of an inhalation anesthetic in which there is complete rebreathing with carbon dioxide absorption.
- defensive c. obsolete term for the addition of a secondary affection that limits or arrests the progress of the primary affection, as thought to occur when pneumothorax supervenes on pulmonary tuberculosis, the former having a therapeutic effect on the latter.
- greater arterial c. of iris SYN: major arterial c. of iris.
- Haller c. 1. SYN: vascular c. of optic nerve. 2. SYN: areolar venous plexus.
- Huguier c. anastomosis around the isthmus of the uterus (junction of the cervix with the body) between the right and left uterine arteries.
- least confusion c. in the configuration of rays emerging from a spherocylindrical lens system, the place where diverging rays of the lens first forming a line image are balanced by converging rays of the second lens.
- lesser arterial c. of iris SYN: minor arterial c. of iris.
- major arterial c. of iris an arterial c. at the ciliary border of the iris. SYN: circulus arteriosus iridis major [TA], major circulus arteriosus of iris [TA], greater arterial c. of iris.
- minor arterial c. of iris an arterial c. near the pupillary margin of the iris. SYN: circulus arteriosus iridis minor [TA], minor circulus arteriosus of iris [TA], lesser arterial c. of iris.
- Pagenstecher c. in the case of a freely movable abdominal tumor, the mass is moved throughout its entire range, its position at intervals being marked on the abdominal wall; when these points are joined, a c. is formed, the center of which marks the point of attachment of the tumor.
- Ridley c. SYN: circular sinus (1).
- rolling c. a mechanism for the replication of circular DNA.
- semi- closed c. a circuit for administration of an inhalation anesthetic in which partial rebreathing with carbon dioxide absorption is combined with loss from the circuit of a portion of respired gases through valves.
- vascular c. 1. the c. around the mouth formed by the inferior and superior labial arteries; 2. SYN: areolar venous plexus.
- vascular c. of optic nerve [TA] a network of branches of the short ciliary arteries on the sclera around the point of entrance of the optic nerve. SYN: circulus vasculosus nervi optici [TA], circulus arteriosus halleri, circulus zinnii, Haller c. (1), Zinn corona, Zinn vascular c..
- venous c. of mammary gland SYN: areolar venous plexus.
- vicious c. the mutually augmenting action of two independent diseases or phenomena, or of a primary and secondary affection;
- Vieth-Müller c. a geometric c. passing through the optical centers of two eyes by which points adjacent to the point of fixation, both lying on the c., theoretically fall on corresponding retinal points.
- c. of Willis SYN: cerebral arterial c..
- Zinn vascular c. SYN: vascular c. of optic nerve.

* * *

cir·cle 'sər-kəl n
1 a) a closed plane curve every point of which is equidistant from a fixed point within the curve
b) the plane surface bounded by such a curve
2) something (as an anatomical part) in the form of a circle or section of a circle <an arterial \circle> see CIRCLE OF WILLIS

* * *

cir·cle (surґkəl) [L. circulus] a round figure, structure, or part. See also anulus and ring.

Medical dictionary. 2011.


Look at other dictionaries:

  • Circle — Cir cle (s[ e]r k l), n. [OE. cercle, F. cercle, fr. L. circulus (Whence also AS. circul), dim. of circus circle, akin to Gr. kri kos, ki rkos, circle, ring. Cf. {Circus}, {Circum }.] [1913 Webster] 1. A plane figure, bounded by a single curve… …   The Collaborative International Dictionary of English

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  • circle — [sʉr′kəl] n. [ME cercle < OFr < L circulus, a circle, dim. of circus: see CIRCUS] 1. a plane figure bounded by a single curved line, every point of which is equally distant from the point at the center of the figure: see CONIC SECTION,… …   English World dictionary

  • Circle — Cir cle, v. t. [imp. & p. p. {Circled}; p. pr. & vb. n. {Circling}.] [OE. cerclen, F. cercler, fr. L. circulare to make round. See {Circle}, n., and cf. {Circulate}.] [1913 Webster] 1. To move around; to revolve around. [1913 Webster] Other… …   The Collaborative International Dictionary of English

  • Circle — Circle, AK U.S. Census Designated Place in Alaska Population (2000): 100 Housing Units (2000): 42 Land area (2000): 107.672614 sq. miles (278.870779 sq. km) Water area (2000): 0.540092 sq. miles (1.398832 sq. km) Total area (2000): 108.212706 sq …   StarDict's U.S. Gazetteer Places

  • Circle — Жанры краут рок психоделический рок пост рок экспериментальный рок Годы 1991 наши дни …   Википедия

  • circle — ► NOUN 1) a round plane figure whose boundary consists of points equidistant from the centre. 2) a group of people or things forming a circle. 3) a curved upper tier of seats in a theatre. 4) a group of people with a shared profession, interests …   English terms dictionary

  • Circle — Cir cle, v. i. To move circularly; to form a circle; to circulate. [1913 Webster] Thy name shall circle round the gaping through. Byron. [1913 Webster] …   The Collaborative International Dictionary of English

  • circle — [n1] orb, loop, round figure amphitheater, aureole, band, belt, bowl, bracelet, circlet, circuit, circumference, circus, cirque, coil, colure, compass, cordon, corona, crown, cycle, disc, disk, ecliptic, enclosure, equator, full turn, globe, halo …   New thesaurus

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  • circle — index bailiwick, contour (outline), cycle, enclosure, encompass (surround), hedge, perambulate …   Law dictionary

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