circle


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circle

 [ser´k'l]
a round figure, structure, or part.
Berry's c's charts with circles on them for testing stereoscopic vision.
cerebral arterial circle circle of Willis.
Minsky's circle a device for the graphic recording of eye lesions.
sensory circle a body area within which it is impossible to distinguish separately the impressions arising from two sites of stimulation.
circle of Willis the anastomotic loop of blood vessels near the base of the brain. Called also cerebral arterial circle.

cir·cle

(ser'kĕl),
1. anatomy a ring-shaped or anular 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.
Synonym(s): circulus [TA]
[L. circulus]

circle

/cir·cle/ (ser´k'l) a round structure or part.
cerebral arterial circle  c. of Willis.
Berry's circles  charts with circles on them for testing stereoscopic vision.
defensive circle  the coexistence of two conditions which tend to have an antagonistic or inhibiting effect on each other.
circle of Haller  a circle of arteries in the sclera at the site of the entrance of the optic nerve.
Minsky's circles  a series of circles used for the graphic recording of eye lesions.
circle of Willis  the anastomotic loop of vessels near the base of the brain.

circle

Etymology: L, circulus
(in anatomy) a circular or nearly circular structure of the body, such as the circle of Willis and circle of Zinn. circular, adj.

cir·cle

(sĭr'kĕl)
1. A ring-shaped structure or group of structures.
Synonym(s): circulus (1) [TA] .
2. A line or process with every point equidistant from the center.
[L. circulus]

cir·cle

(sĭr'kĕl)
anatomy ring-shaped or anular structure or group of structures, as formed by anastomosing arteries or veins, or by connected (communicating) nerves.
[L. circulus]

circle

a round figure, structure or part.

circle block
see ring block.
ciliary arterial circle
formed from the anterior ciliary arteries; lies within the ciliary muscle.
iridial arterial circle
formed from the posterior long ciliary arteries and supplying blood to the iris.
iridial vascular circle
a ring of vessels formed by the anterior ciliary arteries; provide fine branches to the iris and ciliary body.
circle of safety
circle system
see breathing circuit.
circle test
walking a horse in a small circle, first one direction then the other, is used in a neurological examination to detect ataxia and abnormalities in proprioception.
circle of Willis
anastomotic loop of vessels near the base of the brain. See cerebral arterial circle.
References in classic literature ?
But this circle had a continuous tendency to draw in upon him.
They remained in a circle about him and his fire, displaying an arrogance of possession that shook his courage born of the morning light.
he cried, savagely shaking his fist at the hungry beasts; and at the sound of his voice the whole circle was agitated, there was a general snarl, and the she-wolf slid up close to him across the snow and watched him with hungry wistfulness.
A singular idea," replied Nicholl; "but it is probable that Kepler did not know the true dimensions of these circles, for the digging of them would have been the work of giants quite impossible for the Selenites.
The one thing which we seek with insatiable desire is to forget ourselves, to be surprised out of our propriety, to lose our sempiternal memory and to do something without knowing how or why; in short to draw a new circle.
The natural world may be conceived of as a system of concentric circles, and we now and then detect in nature slight dislocations which apprise us that this surface on which we now stand is not fixed, but sliding.
Whilst the eternal generation of circles proceeds, the eternal generator abides.
He saw the silent circle, with gleaming eyes, lolling tongues, and silvery breaths drifting upward, closing in upon him as he had seen similar circles close in upon beaten antagonists in the past.
The circle had tightened till he could feel the breaths of the huskies on his flanks.
The third circle with which Anna had ties was preeminently the fashionable world--the world of balls, of dinners, of sumptuous dresses, the world that hung on to the court with one hand, so as to avoid sinking to the level of the demi-monde.
Anna had at first avoided as far as she could Princess Tverskaya's world, because it necessitated an expenditure beyond her means, and besides in her heart she preferred the first circle.
While doing justice to the intellectual power with which a few Circles have for many generations maintained their supremacy over immense multitudes of their countrymen, he believes that the facts of Flatland, speaking for themselves without comment on his part, declare that Revolutions cannot always be suppressed by slaughter, and that Nature, in sentencing the Circles to infecundity, has condemned them to ultimate failure -- "and herein," he says, "I see a fulfilment of the great Law of all worlds, that while the wisdom of Man thinks it is working one thing, the wisdom of Nature constrains it to work another, and quite a different and far better thing.