cone

cone

 [kōn]

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

2. one of the conelike structures which, with the rods, form the light-sensitive elements of the retina; the cones make possible the perception of color. See also eye and vision. Called also retinal cone.

3. in radiology, a conical or open-ended cylindrical structure formerly used as an aid in centering the radiation beam and as a guide to source-to-film distance. Cones were commonly attached to the x-ray tube prior to the use of the collimator.

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.

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

gutta-percha cone in root canal therapy, a plastic radiopaque cone made from gutta-percha and other ingredients, available in standard sizes according to the dimensions of root canal reamers and files; used to fill and seal the canal along with sealer cements. Called also gutta-percha point.

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 cone cone (def. 2).

silver cone silver point.

Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

cone

(kōn),

1. A surface joining a circle to a point above the plane containing the circle.

2. The photosensitive, outward-directed, conic process of a cone cell essential for sharp vision and color vision; cones are the only photoreceptors in the fovea centralis and become interspersed with increasing numbers of rods toward the periphery of the retina. Synonym(s): cone cell of retina

3. Metallic cylinder or truncated cone, either circular or square in cross-section, used to confine a beam of x-rays.

Synonym(s): conus (1)

[G. kōnos, cone]

Farlex Partner Medical Dictionary © Farlex 2012

cone

(kōn)

n.

Physiology One of the photoreceptors in the retina of the eye that is responsible for daylight and color vision. These photoreceptors are most densely concentrated in the fovea centralis, creating the area of greatest visual acuity. Also called cone cell.

The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

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.

McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

cone

(kōn)

1. A surface joining a circle to a point above the plane containing the circle.

2. The photosensitive, outward-directed, conical process of a cone cell essential for sharp vision and color vision; cones are the only photoreceptor in the fovea centralis and become interspersed with increasing numbers of rods toward the periphery of the retina.

3. Metallic cylinder or truncated cone, either circular or square in cross-section, used to confine a beam of x-rays.
Synonym(s): conus (1) .

[G. kōnos, cone]

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

cone

1. (in plants) a reproductive structure in the form of a conical mass of scale-like sporophylls surrounding a central axis, found particularly in GYMNOSPERMS but also in other plant groups, e.g. horsetails (Equisetales).
2. (in animals) a light-sensitive structure in the vertebrate eye. See CONE CELL.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

cone

(kōn)

1. A surface joining a circle to a point above the plane containing the circle.

2. Metallic cylinder or truncated cone used to confine a beam of x-rays.

[G. kōnos, cone]

Medical Dictionary for the Dental Professions © Farlex 2012