cone (redirected from right circular cone)

cone (kōn)

1. a solid figure or body having a circular base and tapering to a point.

2. retinal c.

3. in radiology, a conical or open-ended cylindrical structure used as an aid in centering the radiation beam and as a guide to source-to-film distance.

4. in root canal therapy, a solid substance with a tapered form, usually made of gutta-percha or silver, fashioned to conform to the shape of a root canal.

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cone of light  the triangular reflection of light seen on the tympanic membrane.

retinal cone  one of the specialized conical or flask-shaped outer segments of the visual cells, which, with the retinal rods, form the light-sensitive elements of the retina.

twin cones  retinal cone cells in which two cells are blended.

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cone (kn) n. 1. A solid body having a circle for its base and sides inclined so as to meet at a point above the base. 2. See cone cell.

cone detail of a retina showing cone and rod cells

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cone

[kōn]

Etymology: Gk, konos, cone

1 a photoreceptor cell in the retina of the eye that enables a person to visualize colors. There are three kinds of retinal cones, one each for the colors blue, green, and red; other colors are seen by stimulation of more than one type of cone.

2 a cone-shaped device attached to radiologic equipment to focus x-rays on a small target of tissue. See also cone biopsy. conic [kon′ik] , conical, adj.

Cone cell of the retina

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cone,

n 1. a geometric shape with a circular base tapering evenly to an apex.
2. a solid substance, usually guttapercha or silver, having a tapered form similar in length and diameter to a root canal; used to fill the space once occupied by the pulp in the root of the tooth.
3. an accessory device on a dental radiograph machine, designed to indicate the direction of the central axis of its radiographic beam and to serve as a guide in establishing a desired source-to-film distance.

cone distance,

n the distance between the focal spot and the outer end of the cone; usually expressed in inches or centimeters. Modern dental roentgen-ray units usually have cone distances of from 5 to 20 inches (12.5 to 50 cm).

cone, long,

n a tubular “cone” designed to establish an extended anode-to-skin distance, usually within a range of from 12 to 20 inches (30 to 50 cm).

cone, sharpening,

n a tapered or straight cylindrical stone that is used primarily to sharpen the curvature of dental instruments. See also stone, Arkansas and stone, Carborundum.

cone, short,

n a conical or tubular “cone” having as one of its functions the establishment of an anode-to-skin distance of up to 9 inches (22.5 cm).

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cone

1. a solid figure or body having a circular base and tapering to a point, especially one of the conelike structures of the retina, which, with the retinal rods, form the light-sensitive elements of the retina. The cones make possible the perception of color.

2. in radiology, a conical or open-ended cylindrical structure used as an aid in producing high detail x-rays.

3. surgical cone.

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cone cells (1)

the commonest, if not the sole, photoreceptors in the central area of the retina, where the function of acute vision is located. See also cone (1) above.

cone down

in radiology, to restrict the x-ray beam. See also collimation.

cone dysplasia (1)

progressive dysplasia of retinal cones in Alaskan malamute dogs; causes impaired day vision from an early age. The rods are normal.

ether cone

a cone-shaped device used over the face in administration of ether for anesthesia.

cone flower

see rudbeckia.

cone of light

the triangular reflection of light seen on the tympanic membrane.

pressure cone

the area of compression exerted by a mass in the brain, as in transtentorial herniation.

retinal c's

see cone (1) above.

cone shellfish

see conus.

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cone

Gynecology Cone biopsy, see there Neurophysiology 1 A color receptor cell in the retina of the eye 2 Growth cone, see there Urogynecology See Vaginal cone.